COVID-19 vaccine#Technology platforms

File:COVID-19 vaccine doses administered by continent.svg|COVID{{nbhyph}}19 vaccine doses administered by continent as of October 11, 2021. For vaccines that require multiple doses, each individual dose is counted. As the same person may receive more than one dose, the number of doses can be higher than the number of people in the population.

File:World map of share of people who received all doses prescribed by the initial COVID-19 vaccination protocol.png|Map showing share of population fully vaccinated against COVID-19 relative to a country's total population{{cite web | work = Our World in Data | title = (OWID) vaccination maps. | url = https://github.com/owid/covid-19-data/tree/master/public/data/vaccinations | archive-url = https://web.archive.org/web/20211221015843/https://github.com/owid/covid-19-data/tree/master/public/data/vaccinations | archive-date=21 December 2021}} {{cite journal | journal = Our World in Data | url = https://ourworldindata.org/covid-vaccinations#frequently-asked-questions | title = Data FAQ | date = 5 March 2020 | archive-url = https://web.archive.org/web/20210310194213/https://ourworldindata.org/covid-vaccinations#frequently-asked-questions | archive-date=10 March 2021 | vauthors = Mathieu E, Ritchie H, Rodés-Guirao L, Appel C, Giattino C, Hasell J, MacDonald B, Dattani S, Beltekian D, Ortiz-Ospina E, Roser M }}

File:COVID Vaccine (50745583447).jpg receiving a COVID{{nbhyph}}19 vaccine, December 2020]]

[[File:COVID-19 vaccine map.svg|thumb|upright=1.2|Map of countries by approval status

{{legend|Green|Approved for general use, mass vaccination underway}}

{{legend|SpringGreen|:w:Emergency Use Authorization (or equivalent) granted, mass vaccination underway}}

{{legend|DodgerBlue|EUA granted, mass vaccination planned}}

{{legend|LightGrey|No data available}}]]

Prior to COVID{{nbhyph}}19, a vaccine for an infectious disease had never been produced in less than several years{{snd}}and no vaccine existed for preventing a coronavirus infection in humans.{{cite web | vauthors = Gates B |date=30 April 2020|title=The vaccine race explained: What you need to know about the COVID-19 vaccine|url=https://www.gatesnotes.com/Health/What-you-need-to-know-about-the-COVID-19-vaccine|archive-url=https://web.archive.org/web/20200514010012/https://www.gatesnotes.com/Health/What-you-need-to-know-about-the-COVID-19-vaccine |archive-date=14 May 2020|url-status=live|access-date=2 May 2020|publisher=The Gates Notes }} However, vaccines have been produced against several animal diseases caused by coronaviruses, including (as of 2003) infectious bronchitis virus in birds, canine coronavirus, and feline coronavirus.{{cite journal |vauthors=Cavanagh D |date=December 2003 |title=Severe acute respiratory syndrome vaccine development: experiences of vaccination against avian infectious bronchitis coronavirus |journal=Avian Pathology |volume=32 |issue=6 |pages=567–582 |doi=10.1080/03079450310001621198 |pmc=7154303 |pmid=14676007 | title-link = doi | doi-access = free }} Previous projects to develop vaccines for viruses in the family Coronaviridae that affect humans have been aimed at severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). Vaccines against SARS{{cite journal |vauthors=Gao W, Tamin A, Soloff A, D'Aiuto L, Nwanegbo E, Robbins PD, Bellini WJ, Barratt-Boyes S, Gambotto A |date=December 2003 |title=Effects of a SARS-associated coronavirus vaccine in monkeys |journal=Lancet |volume=362 |issue=9399 |pages=1895–1896 |doi=10.1016/S0140-6736(03)14962-8 |pmc=7112457 |pmid=14667748 | title-link = doi | doi-access = free }} and MERS{{cite journal |vauthors=Kim E, Okada K, Kenniston T, Raj VS, AlHajri MM, Farag EA, AlHajri F, Osterhaus AD, Haagmans BL, Gambotto A |date=October 2014 |title=Immunogenicity of an adenoviral-based Middle East Respiratory Syndrome coronavirus vaccine in BALB/c mice |journal=Vaccine |volume=32 |issue=45 |pages=5975–5982 |doi=10.1016/j.vaccine.2014.08.058 |pmc=7115510 |pmid=25192975 | title-link = doi | doi-access = free }} have been tested in non-human animals.

According to studies published in 2005 and 2006, the identification and development of novel vaccines and medicines to treat SARS was a priority for governments and public health agencies around the world at that time.{{cite journal |vauthors=Greenough TC, Babcock GJ, Roberts A, Hernandez HJ, Thomas WD, Coccia JA, Graziano RF, Srinivasan M, Lowy I, Finberg RW, Subbarao K, Vogel L, Somasundaran M, Luzuriaga K, Sullivan JL, Ambrosino DM |date=February 2005 |title=Development and characterization of a severe acute respiratory syndrome-associated coronavirus-neutralizing human monoclonal antibody that provides effective immunoprophylaxis in mice |journal=The Journal of Infectious Diseases |volume=191 |issue=4 |pages=507–514 |doi=10.1086/427242 |pmc=7110081 |pmid=15655773 | title-link = doi | doi-access = free }}{{cite journal |vauthors=Tripp RA, Haynes LM, Moore D, Anderson B, Tamin A, Harcourt BH, Jones LP, Yilla M, Babcock GJ, Greenough T, Ambrosino DM, Alvarez R, Callaway J, Cavitt S, Kamrud K, Alterson H, Smith J, Harcourt JL, Miao C, Razdan R, Comer JA, Rollin PE, Ksiazek TG, Sanchez A, Rota PA, Bellini WJ, Anderson LJ |date=September 2005 |title=Monoclonal antibodies to SARS-associated coronavirus (SARS-CoV): identification of neutralizing and antibodies reactive to S, N, M and E viral proteins |journal=Journal of Virological Methods |volume=128 |issue=1–2 |pages=21–28 |doi=10.1016/j.jviromet.2005.03.021 |pmc=7112802 |pmid=15885812}}{{cite journal |vauthors=Roberts A, Thomas WD, Guarner J, Lamirande EW, Babcock GJ, Greenough TC, Vogel L, Hayes N, Sullivan JL, Zaki S, Subbarao K, Ambrosino DM |date=March 2006 |title=Therapy with a severe acute respiratory syndrome-associated coronavirus-neutralizing human monoclonal antibody reduces disease severity and viral burden in golden Syrian hamsters |journal=The Journal of Infectious Diseases |volume=193 |issue=5 |pages=685–692 |doi=10.1086/500143 |pmc=7109703 |pmid=16453264}} There is no cure or protective vaccine proven to be safe and effective against SARS in humans.{{cite journal |vauthors=Jiang S, Lu L, Du L |date=January 2013 |title=Development of SARS vaccines and therapeutics is still needed |journal=Future Virology |volume=8 |issue=1 |pages=1–2 |doi=10.2217/fvl.12.126 |pmc=7079997 |pmid=32201503}}{{cite web |date=5 March 2020|title=SARS (severe acute respiratory syndrome)|url=https://www.nhs.uk/conditions/sars/|archive-url=https://web.archive.org/web/20200309174230/https://www.nhs.uk/conditions/sars/|archive-date=9 March 2020|url-status=live|access-date=31 January 2020|publisher=National Health Service}} There is also no proven vaccine against MERS.{{cite journal |vauthors=Shehata MM, Gomaa MR, Ali MA, Kayali G |date=June 2016 |title=Middle East respiratory syndrome coronavirus: a comprehensive review |journal=Frontiers of Medicine |volume=10 |issue=2 |pages=120–136 |doi=10.1007/s11684-016-0430-6 |pmc=7089261 |pmid=26791756}} When MERS became prevalent, it was believed that existing SARS research might provide a useful template for developing vaccines and therapeutics against a MERS-CoV infection.{{cite journal |vauthors=Butler D |date=October 2012 |title=SARS veterans tackle coronavirus |journal=Nature |volume=490 |issue=7418 |pages=20 |bibcode=2012Natur.490...20B |doi=10.1038/490020a |pmid=23038444 | title-link = doi | doi-access = free }} As of March 2020, there was one (DNA-based) MERS vaccine that completed Phase{{spaces}}I clinical trials in humans,{{cite journal |vauthors=Modjarrad K, Roberts CC, Mills KT, Castellano AR, Paolino K, Muthumani K, Reuschel EL, Robb ML, Racine T, Oh MD, Lamarre C, Zaidi FI, Boyer J, Kudchodkar SB, Jeong M, Darden JM, Park YK, Scott PT, Remigio C, Parikh AP, Wise MC, Patel A, Duperret EK, Kim KY, Choi H, White S, Bagarazzi M, May JM, Kane D, Lee H, Kobinger G, Michael NL, Weiner DB, Thomas SJ, Maslow JN |date=September 2019 |title=Safety and immunogenicity of an anti-Middle East respiratory syndrome coronavirus DNA vaccine: a phase 1, open-label, single-arm, dose-escalation trial |journal=The Lancet. Infectious Diseases |volume=19 |issue=9 |pages=1013–1022 |doi=10.1016/S1473-3099(19)30266-X |pmc=7185789 |pmid=31351922 | title-link = doi | doi-access = free }} and three others in progress, all being viral-vectored vaccines: two adenoviral-vectored (ChAdOx1-MERS, BVRS-GamVac) and one MVA-vectored (MVA-MERS-S).{{cite journal |vauthors=Yong CY, Ong HK, Yeap SK, Ho KL, Tan WS |year=2019 |title=Recent Advances in the Vaccine Development Against Middle East Respiratory Syndrome-Coronavirus |journal=Frontiers in Microbiology |volume=10 |pages=1781 |doi=10.3389/fmicb.2019.01781 |pmc=6688523 |pmid=31428074 | title-link = doi | doi-access = free }}

Vaccines that use an inactive or weakened virus that has been grown in eggs typically take more than a decade to develop.{{cite news |vauthors=Loftus P, Hopkins JS, Pancevski B |title=Moderna and Pfizer Are Reinventing Vaccines, Starting With Covid |url=https://www.wsj.com/articles/moderna-and-pfizer-are-reinventing-vaccines-starting-with-covid-11605638892 |access-date=4 October 2021 |work=The Wall Street Journal |date=17 November 2020 |archive-date=6 November 2021 |archive-url=https://web.archive.org/web/20211106035936/https://www.wsj.com/articles/moderna-and-pfizer-are-reinventing-vaccines-starting-with-covid-11605638892 |url-status=live }}{{cite journal | vauthors = Sharma O, Sultan AA, Ding H, Triggle CR | title = A Review of the Progress and Challenges of Developing a Vaccine for COVID-19 | journal = Frontiers in Immunology | volume = 11 | pages = 585354 | date = 14 October 2020 | pmid = 33163000 | pmc = 7591699 | doi = 10.3389/fimmu.2020.585354 | title-link = doi | doi-access = free }} In contrast, mRNA is a molecule that can be made quickly, and research on mRNA to fight diseases was begun decades before the COVID{{nbhyph}}19 pandemic by scientists such as Drew Weissman and Katalin Karikó, who tested on mice. Moderna began human testing of an mRNA vaccine in 2015. Viral vector vaccines were also developed for the COVID{{nbhyph}}19 pandemic after the technology was previously cleared for Ebola.

As multiple COVID{{nbhyph}}19 vaccines have been authorized or licensed for use, real-world vaccine effectiveness (RWE) is being assessed using case control and observational studies.{{cite journal|author4-link=John R. Mascola | vauthors = Bok K, Sitar S, Graham BS, Mascola JR | title = Accelerated COVID-19 vaccine development: milestones, lessons, and prospects | journal = Immunity | volume = 54 | issue = 8 | pages = 1636–1651 | date = August 2021 | pmid = 34348117 | pmc = 8328682 | doi = 10.1016/j.immuni.2021.07.017 }}{{cite web |vauthors=Lewis T |title=The New COVID Booster Shot Could Save Your Life; Get One Now, FDA Expert Says |url=https://www.scientificamerican.com/article/the-new-covid-booster-shot-could-save-your-life-get-one-now-fda-expert-says/ |access-date=8 November 2022 |website=Scientific American |archive-date=7 November 2022 |archive-url=https://web.archive.org/web/20221107182453/https://www.scientificamerican.com/article/the-new-covid-booster-shot-could-save-your-life-get-one-now-fda-expert-says/ |url-status=live }} A study is investigating the long-lasting protection against SARS-CoV-2 provided by the mRNA vaccines.{{cite journal | vauthors = Turner JS, O'Halloran JA, Kalaidina E, Kim W, Schmitz AJ, Zhou JQ, Lei T, Thapa M, Chen RE, Case JB, Amanat F, Rauseo AM, Haile A, Xie X, Klebert MK, Suessen T, Middleton WD, Shi PY, Krammer F, Teefey SA, Diamond MS, Presti RM, Ellebedy AH | title = SARS-CoV-2 mRNA vaccines induce persistent human germinal centre responses | journal = Nature | volume = 596 | issue = 7870 | pages = 109–113 | date = August 2021 | pmid = 34182569 | doi = 10.1038/s41586-021-03738-2 | bibcode = 2021Natur.596..109T | title-link = doi | doi-access = free | pmc = 8935394 }}{{cite news | title=Pfizer and Moderna Vaccines Likely to Produce Lasting Immunity, Study Finds | work=The New York Times | date=28 June 2021 | url=https://www.nytimes.com/2021/06/28/health/coronavirus-vaccines-immunity.html |archive-url=https://web.archive.org/web/20210628091525/https://www.nytimes.com/2021/06/28/health/coronavirus-vaccines-immunity.html |archive-date=28 June 2021 |url-access=subscription |url-status=live | access-date=23 January 2022}}

File:Vaccine candidate mechanisms for SARS-CoV-2 (49948301838).jpg; (2) subunit vaccine; (3) viral vector vaccine]]

File:Fimmu-11-579250-g004.jpg and inactivated forms of the virus. Protein and peptide subunit vaccines are usually combined with an adjuvant in order to enhance immunogenicity. The main emphasis in SARS-CoV-2 vaccine development has been on using the whole spike protein in its trimeric form, or components of it, such as the RBD region. Multiple non-replicating viral vector vaccines have been developed, particularly focused on adenovirus, while there has been less emphasis on the replicating viral vector constructs.{{cite journal |vauthors=Flanagan KL, Best E, Crawford NW, Giles M, Koirala A, Macartney K, Russell F, Teh BW, Wen SC |date=2020 |title=Progress and Pitfalls in the Quest for Effective SARS-CoV-2 (COVID-19) Vaccines |journal=Frontiers in Immunology |volume=11 |pages=579250 |doi=10.3389/fimmu.2020.579250 |pmc=7566192 |pmid=33123165 | title-link = doi | doi-access = free }}]] The initial focus of SARS-CoV-2 vaccines was on preventing symptomatic, often severe, illness.{{cite journal | vauthors = Subbarao K |date=July 2021 |title=The success of SARS-CoV-2 vaccines and challenges ahead |journal=Cell Host & Microbe |volume=29 |issue=7 |pages=1111–1123 |doi=10.1016/j.chom.2021.06.016 |pmc=8279572 |pmid=34265245 | title-link = doi | doi-access = free }} Most of the first COVID{{nbhyph}}19 vaccines were two-dose vaccines, with the exception single-dose vaccines Convidecia{{cite web |title=The CanSino Biologics Ad5-nCoV-S [recombinant] COVID-19 vaccine: What you need to know |url=https://www.who.int/news-room/feature-stories/detail/the--cansino-biologics-ad5-ncov-s--recombinant---covid-19-vaccine--what-you-need-to-know |website=www.who.int |access-date=12 July 2024 }} and the Janssen COVID‑19 vaccine, and vaccines with three-dose schedules, Razi Cov Pars{{cite journal | vauthors = Dodaran MS, Banihashemi SR, Es-haghi A, Mehrabadi MH, Nofeli M, Mokarram AR, Mokhberalsafa L, Sadeghi F, Ranjbar A, Ansarifar A, Mohazzab A, Setarehdan SA, Bagheri Amiri F, Mohseni V, Hajimoradi M, Ghahremanzadeh N, Razzaz SH, Masoomi S, Taghdiri M, Bagheri M, Lofti M, Khorasani A, Ghader M, Safari S, Shahsavn M, Kalantari S |title=Immunogenicity and Safety of a Combined Intramuscular/Intranasal Recombinant Spike Protein COVID-19 Vaccine (RCP) in Healthy Adults Aged 18 to 55 Years Old: A Randomized, Double-Blind, Placebo-Controlled, Phase I Trial |journal=Vaccines |date=16 February 2023 |volume=11 |issue=2 |pages=455 |doi=10.3390/vaccines11020455 |doi-access=free |pmid=36851334 |pmc=9961243 }} and Soberana.{{cite journal | vauthors = Puga-Gómez R, Ricardo-Delgado Y, Rojas-Iriarte C, Céspedes-Henriquez L, Piedra-Bello M, Vega-Mendoza D, Pérez NP, Paredes-Moreno B, Rodríguez-González M, Valenzuela-Silva C, Sánchez-Ramírez B, Rodríguez-Noda L, Pérez-Nicado R, González-Mugica R, Hernández-García T, Fundora-Barrios T, Echevarría MD, Enriquez-Puertas JM, Infante-Hernández Y, Palenzuela-Díaz A, Gato-Orozco E, Chappi-Estévez Y, Francisco-Pérez JC, Suarez-Martinez M, Castillo-Quintana IC, Fernandez-Castillo S, Climent-Ruiz Y, Santana-Mederos D, García-Vega Y, Toledo-Romani ME, Doroud D, Biglari A, Valdés-Balbín Y, García-Rivera D, Vérez-Bencomo V, Mesa-Herrera ME, García-Cristiá Y, Verdecia-Sánchez L, del Valle Rodríguez R, Oquendo-de la Cruz Y, Álvarez-Montalvo D, Grillo-Fortún R, López-González L, Galindo OF, Reyes-González Y, González-Álvarez AB, Gorrita-Mora L, Valera-Fernández R, Ontivero-Pino I, Martínez-Pérez M, Caballero-Gonzalez E, Garcés-Hechavarría A, Martínez-Bedoya D, Medina-Nápoles M, Domínguez-Pentón YR, Cazañas-Quintana Y, Barrios TF, Fernández DR, Bergado-Báez G, Orosa-Vazquez I, Pi-Estopiñan F, Díaz-Hernández M, Cruz-Sui O, Noa-Romero E, García-López A, Muro SR, Baro-Roman G |title=Open-label phase I/II clinical trial of SARS-CoV-2 receptor binding domain-tetanus toxoid conjugate vaccine (FINLAY-FR-2) in combination with receptor binding domain-protein vaccine (FINLAY-FR-1A) in children |journal=International Journal of Infectious Diseases |date=January 2023 |volume=126 |pages=164–173 |doi=10.1016/j.ijid.2022.11.016 |pmid=36403819 |pmc=9673084 |url=https://www.ijidonline.com/article/S1201-9712(22)00601-4/fulltext |access-date=28 June 2024}}

As of July 2021, at least nine different technology platforms were under research and development to create an effective vaccine against COVID{{nbhyph}}19.{{cite web |date=12 July 2021 |title=COVID-19 vaccine tracker (Refresh URL to update) |url=https://vac-lshtm.shinyapps.io/ncov_vaccine_landscape/ |url-status=live |archive-url=https://web.archive.org/web/20201011084722/https://vac-lshtm.shinyapps.io/ncov_vaccine_landscape// |archive-date=11 October 2020 |access-date=10 March 2021 |publisher=London School of Hygiene & Tropical Medicine}} Most of the platforms of vaccine candidates in clinical trials are focused on the coronavirus spike protein (S protein) and its variants as the primary antigen of COVID{{nbhyph}}19 infection, since the S protein triggers strong B-cell and T-cell immune responses.{{cite journal |vauthors=Arbeitman CR, Rojas P, Ojeda-May P, Garcia ME |date=September 2021 |title=The SARS-CoV-2 spike protein is vulnerable to moderate electric fields |journal=Nature Communications |volume=12 |issue=1 |pages=5407 |arxiv=2103.12733 |bibcode=2021NatCo..12.5407A |doi=10.1038/s41467-021-25478-7 |pmc=8437970 |pmid=34518528 | title-link = doi | doi-access = free }}{{cite journal |vauthors=Grifoni A, Weiskopf D, Ramirez SI, Mateus J, Dan JM, Moderbacher CR, Rawlings SA, Sutherland A, Premkumar L, Jadi RS, Marrama D, de Silva AM, Frazier A, Carlin AF, Greenbaum JA, Peters B, Krammer F, Smith DM, Crotty S, Sette A |date=June 2020 |title=Targets of T Cell Responses to SARS-CoV-2 Coronavirus in Humans with COVID-19 Disease and Unexposed Individuals |journal=Cell |volume=181 |issue=7 |pages=1489–1501.e15 |doi=10.1016/j.cell.2020.05.015 |pmc=7237901 |pmid=32473127}} However, other coronavirus proteins are also being investigated for vaccine development, like the nucleocapsid, because they also induce a robust T-cell response and their genes are more conserved and recombine less frequently.{{cite journal |vauthors=Dutta NK, Mazumdar K, Gordy JT |date=June 2020 |title=The Nucleocapsid Protein of SARS-CoV-2: a Target for Vaccine Development |journal=Journal of Virology |volume=94 |issue=13 |doi=10.1128/JVI.00647-20 |pmc=7307180 |pmid=32546606 |veditors=Dutch RE}}{{cite journal |vauthors=Nikolaidis M, Markoulatos P, Van de Peer Y, Oliver SG, Amoutzias GD |date=October 2021 |title=The neighborhood of the Spike gene is a hotspot for modular intertypic homologous and non-homologous recombination in Coronavirus genomes |journal=Molecular Biology and Evolution |volume=39 |pages=msab292 |doi=10.1093/molbev/msab292 |pmc=8549283 |pmid=34638137 |veditors=Hepp C}} Future generations of COVID{{nbhyph}}19 vaccines targeting more conserved genomic regions could be used to treat future variations of SARS-CoV-2, or any similar coronavirus epidemic/pandemic.{{cite journal |vauthors=Amoutzias GD, Nikolaidis M, Tryfonopoulou E, Chlichlia K, Markoulatos P, Oliver SG |date=January 2022 |title=The Remarkable Evolutionary Plasticity of Coronaviruses by Mutation and Recombination: Insights for the COVID-19 Pandemic and the Future Evolutionary Paths of SARS-CoV-2 |journal=Viruses |volume=14 |issue=1 |pages=78 |doi=10.3390/v14010078 |pmc=8778387 |pmid=35062282 | title-link = doi | doi-access = free }}

Platforms developed in 2020 involved nucleic acid technologies (nucleoside-modified messenger RNA and DNA), non-replicating viral vectors, peptides, recombinant proteins, live attenuated viruses, and inactivated viruses.

Many vaccine technologies being developed for COVID{{nbhyph}}19 use "next-generation" strategies for precise targeting of COVID{{nbhyph}}19 infection mechanisms. Several of the synthetic vaccines use a 2P mutation to lock the spike protein into its prefusion configuration, stimulating an adaptive immune response to the virus before it attaches to a human cell.{{cite magazine |date=29 September 2020 |title=The tiny tweak behind COVID-19 vaccines |url=https://cen.acs.org/pharmaceuticals/vaccines/tiny-tweak-behind-COVID-19/98/i38 |url-status=live |magazine=Chemical & Engineering News |volume=98 |issue=38 |archive-url=https://web.archive.org/web/20210216151009/https://cen.acs.org/pharmaceuticals/vaccines/tiny-tweak-behind-COVID-19/98/i38 |archive-date=16 February 2021 |access-date=15 April 2021 |vauthors=Cross R}} Vaccine platforms in development may improve flexibility for antigen manipulation and effectiveness for targeting mechanisms of COVID{{nbhyph}}19 infection in susceptible population subgroups, such as healthcare workers, the elderly, children, pregnant women, and people with weakened immune systems.

{{anchor|RNA-based}}

{{Further|mRNA vaccine}}

File:RNA vaccine illustration (en).jpg. Messenger RNA contained in the vaccine enters cells and is translated into foreign proteins, which trigger an immune response.]]

Several COVID{{nbhyph}}19 vaccines, such as the Pfizer–BioNTech and Moderna vaccines, use RNA to stimulate an immune response. When introduced into human tissue, the vaccine contains either self-replicating RNA or messenger RNA (mRNA), which both cause cells to express the SARS-CoV-2 spike protein. This teaches the immune system how to identify and destroy the corresponding pathogen. RNA vaccines often use nucleoside-modified messenger RNA. The delivery of mRNA is achieved by a coformulation of the molecule into lipid nanoparticles, which protect the RNA strands and help their absorption into the cells.{{cite journal |vauthors=Krammer F |date=October 2020 |title=SARS-CoV-2 vaccines in development |journal=Nature |volume=586 |issue=7830 |pages=516–527 |bibcode=2020Natur.586..516K |doi=10.1038/s41586-020-2798-3 |pmid=32967006 | title-link = doi | doi-access = free |s2cid=221887746}}{{cite journal |vauthors=Park KS, Sun X, Aikins ME, Moon JJ |date=February 2021 |title=Non-viral COVID-19 vaccine delivery systems |journal=Advanced Drug Delivery Reviews |volume=169 |pages=137–151 |doi=10.1016/j.addr.2020.12.008 |issn=0169-409X |pmc=7744276 |pmid=33340620}}{{cite journal |vauthors=Kowalski PS, Rudra A, Miao L, Anderson DG |date=April 2019 |title=Delivering the Messenger: Advances in Technologies for Therapeutic mRNA Delivery |journal=Molecular Therapy |volume=27 |issue=4 |pages=710–728 |doi=10.1016/j.ymthe.2019.02.012 |pmc=6453548 |pmid=30846391}}{{cite journal |vauthors=Verbeke R, Lentacker I, De Smedt SC, Dewitte H |date=October 2019 |title=Three decades of messenger RNA vaccine development |url=https://biblio.ugent.be/publication/8628303 |url-status=live |journal=Nano Today |volume=28 |pages=100766 |doi=10.1016/j.nantod.2019.100766 |archive-url=https://web.archive.org/web/20211009201713/https://biblio.ugent.be/publication/8628303 |archive-date=9 October 2021 |access-date=17 January 2021 |hdl-access=free |hdl=1854/LU-8628303 |s2cid=202221207}}

RNA vaccines are the first COVID{{nbhyph}}19 vaccines to be authorized in the United Kingdom, the United States, and the European Union.{{cite web |title=COVID-19 ACIP Vaccine Recommendations |url=https://www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/covid-19.html |url-status=live |archive-url=https://web.archive.org/web/20211103224932/https://www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/covid-19.html |archive-date=3 November 2021 |access-date=18 February 2021 |website=U.S. Centers for Disease Control and Prevention (CDC)}}{{cite web |title=Safe COVID-19 vaccines for Europeans |url=https://ec.europa.eu/info/live-work-travel-eu/coronavirus-response/safe-covid-19-vaccines-europeans_en |url-status=live |archive-url=https://web.archive.org/web/20211104111910/https://ec.europa.eu/info/live-work-travel-eu/coronavirus-response/safe-covid-19-vaccines-europeans_en |archive-date=4 November 2021 |access-date=19 February 2021 |website=European Commission}} Authorized vaccines of this type include the Pfizer–BioNTech{{cite web |date=9 December 2020 |title=Regulatory Decision Summary – Pfizer–BioNTech COVID-19 Vaccine |url=https://covid-vaccine.canada.ca/info/regulatory-decision-summary-detailTwo.html?linkID=RDS00730 |url-status=live |archive-url=https://web.archive.org/web/20210130120400/https://covid-vaccine.canada.ca/info/regulatory-decision-summary-detailTwo.html?linkID=RDS00730 |archive-date=30 January 2021 |access-date=9 December 2020 |publisher=Health Canada, Government of Canada}}{{cite web |date=30 April 2020 |title=Study to Describe the Safety, Tolerability, Immunogenicity, and Efficacy of RNA Vaccine Candidates Against COVID-19 in Healthy Adults |url=https://clinicaltrials.gov/ct2/show/NCT04368728 |url-status=live |archive-url=https://web.archive.org/web/20201011084828/https://clinicaltrials.gov/ct2/show/NCT04368728/ |archive-date=11 October 2020 |access-date=14 July 2020 |website=ClinicalTrials.gov |id=NCT04368728}}{{cite web |date=14 April 2020 |title=A Multi-site Phase I/II, 2-Part, Dose-Escalation Trial Investigating the Safety and Immunogenicity of four Prophylactic SARS-CoV-2 RNA Vaccines Against COVID-19 Using Different Dosing Regimens in Healthy Adults |url=https://www.clinicaltrialsregister.eu/ctr-search/trial/2020-001038-36/DE |url-status=live |archive-url=https://web.archive.org/web/20200422111024/https://www.clinicaltrialsregister.eu/ctr-search/trial/2020-001038-36/DE |archive-date=22 April 2020 |access-date=22 April 2020 |website=EU Clinical Trials Register |id=EudraCT 2020-001038-36}} and Moderna vaccines.{{cite web |date=14 July 2020 |title=A Study to Evaluate Efficacy, Safety, and Immunogenicity of mRNA-1273 Vaccine in Adults Aged 18 Years and Older to Prevent COVID-19 |url=https://clinicaltrials.gov/ct2/show/NCT04470427 |url-status=live |archive-url=https://web.archive.org/web/20201011084833/https://clinicaltrials.gov/ct2/show/NCT04470427/ |archive-date=11 October 2020 |access-date=27 July 2020 |website=ClinicalTrials.gov |id=NCT04470427}}{{cite news |date=27 July 2020 |title=COVID-19 vaccine candidate heads to widespread testing in U.S. |publisher=NPR |url=https://www.npr.org/sections/coronavirus-live-updates/2020/07/27/895672859/us-vaccine-candidate-heads-to-widespread-testing-in-people |url-status=live |access-date=27 July 2020 |archive-url=https://web.archive.org/web/20201011084836/https://www.npr.org/sections/coronavirus-live-updates/2020/07/27/895672859/us-vaccine-candidate-heads-to-widespread-testing-in-people/ |archive-date=11 October 2020 |vauthors=Palca J}} The CVnCoV RNA vaccine from CureVac failed in clinical trials.{{cite press release |title=CureVac Final Data from Phase 2b/3 Trial of First-Generation COVID-19 Vaccine Candidate, CVnCoV, Demonstrates Protection in Age Group of 18 to 60 |date=30 June 2021 |url=https://www.curevac.com/en/2021/06/30/curevac-final-data-from-phase-2b-3-trial-of-first-generation-covid-19-vaccine-candidate-cvncov-demonstrates-protection-in-age-group-of-18-to-60/ |access-date=2 July 2021 |website=CureVac |archive-date=12 October 2021 |archive-url=https://web.archive.org/web/20211012213635/https://www.curevac.com/en/2021/06/30/curevac-final-data-from-phase-2b-3-trial-of-first-generation-covid-19-vaccine-candidate-cvncov-demonstrates-protection-in-age-group-of-18-to-60/}}

Severe allergic reactions are rare. In December 2020, 1,893,360 first doses of Pfizer–BioNTech COVID{{nbhyph}}19 vaccine administration resulted in 175 cases of severe allergic reactions, of which 21 were anaphylaxis.{{cite journal |vauthors=Moghimi SM |date=March 2021 |title=Allergic Reactions and Anaphylaxis to LNP-Based COVID-19 Vaccines |journal=Molecular Therapy |volume=29 |issue=3 |pages=898–900 |doi=10.1016/j.ymthe.2021.01.030 |pmc=7862013 |pmid=33571463}} For 4,041,396 Moderna COVID{{nbhyph}}19 vaccine dose administrations in December 2020 and January 2021, only ten cases of anaphylaxis were reported. Lipid nanoparticles (LNPs) were most likely responsible for the allergic reactions.

{{anchor|viral vector}}

These vaccines are examples of non-replicating viral vector vaccines using an adenovirus shell containing DNA that encodes a SARS‑CoV‑2 protein.{{cite web |year=2020 |title=What are viral vector-based vaccines and how could they be used against COVID-19? |url=https://www.gavi.org/vaccineswork/what-are-viral-vector-based-vaccines-and-how-could-they-be-used-against-covid-19 |url-status=live |archive-url=https://web.archive.org/web/20211111054019/https://www.gavi.org/vaccineswork/what-are-viral-vector-based-vaccines-and-how-could-they-be-used-against-covid-19 |archive-date=11 November 2021 |access-date=26 January 2021 |publisher=Gavi, the Vaccine Alliance (GAVI)}}{{cite web |date=13 April 2021 |title=Understanding Viral Vector COVID-19 Vaccines |url=https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/viralvector.html |url-status=live |archive-url=https://web.archive.org/web/20211113223939/https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/viralvector.html |archive-date=13 November 2021 |access-date=19 April 2021 |website=U.S. Centers for Disease Control and Prevention (CDC)}} The viral vector-based vaccines against COVID{{nbhyph}}19 are non-replicating, meaning that they do not make new virus particles but rather produce only the antigen that elicits a systemic immune response.

Authorized vaccines of this type include the Oxford–AstraZeneca COVID‑19 vaccine,{{cite web |date=26 May 2020 |title=Investigating a Vaccine Against COVID-19 |url=https://clinicaltrials.gov/ct2/show/NCT04400838 |url-status=live |archive-url=https://web.archive.org/web/20201011084750/https://clinicaltrials.gov/ct2/show/NCT04400838/ |archive-date=11 October 2020 |access-date=14 July 2020 |website=ClinicalTrials.gov |id=NCT04400838}}{{cite web |date=21 April 2020 |title=A Phase 2/3 study to determine the efficacy, safety and immunogenicity of the candidate Coronavirus Disease (COVID-19) vaccine ChAdOx1 nCoV-19 |url=https://www.clinicaltrialsregister.eu/ctr-search/trial/2020-001228-32/GB |url-status=live |archive-url=https://web.archive.org/web/20201005201654/https://www.clinicaltrialsregister.eu/ctr-search/trial/2020-001228-32/GB |archive-date=5 October 2020 |access-date=3 August 2020 |website=EU Clinical Trials Register |id=EudraCT 2020-001228-32}}{{cite journal |vauthors=O'Reilly P |date=May 2020 |title=A Phase III study to investigate a vaccine against COVID-19 |doi=10.1186/ISRCTN89951424 | title-link = doi | doi-access = free |website=ISRCTN Registry}} the Sputnik V COVID‑19 vaccine,{{cite news |date=8 January 2021 |title=How Gamaleya's Vaccine Works |work=The New York Times |url=https://www.nytimes.com/interactive/2021/health/gamaleya-covid-19-vaccine.html |url-status=live |access-date=27 January 2021 |archive-url=https://web.archive.org/web/20210420022117/https://www.nytimes.com/interactive/2021/health/gamaleya-covid-19-vaccine.html |archive-date=20 April 2021 |vauthors=Corum J, Carl Z}} Convidecia, and the Janssen COVID‑19 vaccine.{{cite web |date=4 August 2020 |title=A Study of Ad26.COV2.S in Adults |url=https://clinicaltrials.gov/ct2/show/NCT04436276 |url-status=live |archive-url=https://web.archive.org/web/20200916063346/https://clinicaltrials.gov/ct2/show/NCT04436276 |archive-date=16 September 2020 |access-date=23 August 2020}}{{cite web |title=A Study of Ad26.COV2.S for the Prevention of SARS-CoV-2-Mediated COVID-19 in Adult Participants |url=https://clinicaltrials.gov/ct2/show/NCT04505722 |url-status=live |archive-url=https://web.archive.org/web/20200926145744/https://clinicaltrials.gov/ct2/show/NCT04505722 |archive-date=26 September 2020 |publisher=US National Library of Medicine}}

Convidecia and Janssen are both single dose vaccines that can be stored under ordinary refrigeration for several months.{{cite news |title=Johnson & Johnson seeks emergency FDA authorization for single-shot coronavirus vaccine |newspaper=The Washington Post |url=https://www.washingtonpost.com/health/2021/02/04/jj-vaccine-fda/ |url-status=live |access-date=10 February 2021 |archive-url=https://web.archive.org/web/20210205160208/https://www.washingtonpost.com/health/2021/02/04/jj-vaccine-fda/ |archive-date=5 February 2021 |vauthors=Johnson C, McGinley L}}{{cite magazine |title=It's not just Johnson & Johnson: China has a single-dose COVID-19 vaccine that's 65% effective |url=https://fortune.com/2021/02/09/china-covid-vaccine-single-dose-cansino-johnson-johnson/ |url-status=live |magazine=Fortune |archive-url=https://web.archive.org/web/20210808130747/https://fortune.com/2021/02/09/china-covid-vaccine-single-dose-cansino-johnson-johnson/ |archive-date=8 August 2021 |access-date=28 February 2021}}

Sputnik V uses Ad26 for its first dose, which is the same as Janssen's only dose, and Ad5 for the second dose, which is the same as Convidecia's only dose.{{cite journal |vauthors=Wu S, Zhong G, Zhang J, Shuai L, Zhang Z, Wen Z, Wang B, Zhao Z, Song X, Chen Y, Liu R, Fu L, Zhang J, Guo Q, Wang C, Yang Y, Fang T, Lv P, Wang J, Xu J, Li J, Yu C, Hou L, Bu Z, Chen W |date=August 2020 |title=A single dose of an adenovirus-vectored vaccine provides protection against SARS-CoV-2 challenge |journal=Nat Commun |volume=11 |issue=1 |pages=4081 |bibcode=2020NatCo..11.4081W |doi=10.1038/s41467-020-17972-1 |pmc=7427994 |pmid=32796842}}

In August 2021, the developers of Sputnik V proposed, in view of the Delta case surge, that Pfizer test the Ad26 component (termed its 'Light' version){{cite press release |title=Single dose vaccine, Sputnik Light, authorized for use in Russia |url=https://sputnikvaccine.com/newsroom/pressreleases/single-dose-vaccine-sputnik-light-authorized-for-use-in-russia/ |access-date=12 August 2021 |website=Sputnik V |archive-date=14 November 2021 |archive-url=https://web.archive.org/web/20211114232050/https://sputnikvaccine.com/newsroom/pressreleases/single-dose-vaccine-sputnik-light-authorized-for-use-in-russia/ |url-status=live}} as a booster shot.{{cite tweet|number=1390274722487746563|user=sputnikvaccine|title=Introducing a new member of the Sputnik family - a single dose Sputnik Light! It's a revolutionary 1-shot COVID-19 vaccine with the 80% efficacy - higher than many 2-shot vaccines. Sputnik Light will double vaccination rates and help to handle epidemic peaks https://t.co/BCybe8yYWU|author=Sputnik V|author-link=Sputnik V|date=6 May 2021|access-date=8 December 2022|archive-url=https://web.archive.org/web/20220508165229/https://twitter.com/sputnikvaccine/status/1390274722487746563|archive-date=8 May 2022|url-status=live}}

{{anchor|inactivated}}

Inactivated vaccines consist of virus particles that are grown in culture and then killed using a method such as heat or formaldehyde to lose disease-producing capacity while still stimulating an immune response.{{cite journal |vauthors=Petrovsky N, Aguilar JC |date=October 2004 |title=Vaccine adjuvants: current state and future trends |journal=Immunology and Cell Biology |volume=82 |issue=5 |pages=488–496 |doi=10.1111/j.0818-9641.2004.01272.x |pmid=15479434 |s2cid=154670}}

Inactivated virus vaccines authorized in China include the Chinese CoronaVac{{cite web |date=12 May 2020 |title=Safety and Immunogenicity Study of Inactivated Vaccine for Prevention of SARS-CoV-2 Infection (COVID-19) (Renqiu) |url=https://clinicaltrials.gov/ct2/show/NCT04383574 |url-status=live |archive-url=https://web.archive.org/web/20201011084809/https://clinicaltrials.gov/ct2/show/NCT04383574/ |archive-date=11 October 2020 |access-date=14 July 2020 |website=ClinicalTrials.gov |id=NCT04383574}}{{cite web |date=2 July 2020 |title=Clinical Trial of Efficacy and Safety of Sinovac's Adsorbed COVID-19 (Inactivated) Vaccine in Healthcare Professionals (PROFISCOV) |url=https://clinicaltrials.gov/ct2/show/NCT04456595 |url-status=live |archive-url=https://web.archive.org/web/20201011084811/https://clinicaltrials.gov/ct2/show/NCT04456595/ |archive-date=11 October 2020 |access-date=3 August 2020 |website=ClinicalTrials.gov |id=NCT04456595}}{{cite journal |author=PT. Bio Farma |date=August 2020 |title=A Phase III, observer-blind, randomized, placebo-controlled study of the efficacy, safety, and immunogenicity of SARS-COV-2 inactivated vaccine in healthy adults aged 18–59 years in Indonesia |url=https://www.ina-registry.org/index.php?act=registry_trial_detail&code_trial=16202009080721WXFM0YX |journal=Registri Penyakit Indonesia |archive-url=https://web.archive.org/web/20201011084814/https://www.ina-registry.org/index.php?act=registry_trial_detail&code_trial=16202009080721WXFM0YX%2F |archive-date=11 October 2020 |access-date=15 August 2020}} and the Sinopharm BIBP{{cite journal |vauthors=Chen W, Al Kaabi N |date=July 2020 |title=A Phase III clinical trial for inactivated novel coronavirus pneumonia (COVID-19) vaccine (Vero cells) |url=http://www.chictr.org.cn/showprojen.aspx?proj=56651 |url-status=live |journal=Chinese Clinical Trial Registry |archive-url=https://web.archive.org/web/20201011084800/http://www.chictr.org.cn/showprojen.aspx?proj=56651%2F |archive-date=11 October 2020 |access-date=15 August 2020}} and WIBP vaccines; there is also the Indian Covaxin, the Russian CoviVac,{{cite web |date=20 February 2021 |title=Russia approves its third COVID-19 vaccine, CoviVac |url=https://www.reuters.com/article/us-health-coronavirus-russia-vaccine-idUSKBN2AK07H |url-status=live |archive-url=https://web.archive.org/web/20210228221729/https://www.reuters.com/article/us-health-coronavirus-russia-vaccine-idUSKBN2AK07H |archive-date=28 February 2021 |access-date=11 April 2021 |website=Reuters |vauthors=Ivanova P}} the Kazakh vaccine QazVac,{{cite web |date=27 April 2021 |title=Kazakhstan rolls out its own COVID-19 vaccine |url=https://www.reuters.com/business/healthcare-pharmaceuticals/kazakhstan-rolls-out-its-own-covid-19-vaccine-2021-04-27/ |url-status=live |archive-url=https://web.archive.org/web/20211104170721/https://www.reuters.com/business/healthcare-pharmaceuticals/kazakhstan-rolls-out-its-own-covid-19-vaccine-2021-04-27/ |archive-date=4 November 2021 |access-date=2 July 2021 |website=Reuters}} and the Iranian COVIran Barekat.{{cite web |date=14 June 2021 |title=FarsNews Agency Iran Licenses Emergency Injection of Home-Made Anti-Coronavirus Vaccine |url=https://www.farsnews.ir/en/news/14000324000606/Iran-Licenses-Emergency-Injecin-f-Hme-Made-Ani-Crnavirs-Vaccine |url-status=live |archive-url=https://web.archive.org/web/20211009201716/https://www.farsnews.ir/en/news/14000324000606/Iran-Licenses-Emergency-Injecin-f-Hme-Made-Ani-Crnavirs-Vaccine |archive-date=9 October 2021 |access-date=25 August 2021 |website=Fars News Agency}} Vaccines in clinical trials include the Valneva COVID{{nbhyph}}19 vaccine.{{cite web |date=31 December 2020 |title=VLA2001 COVID-19 Vaccine |url=https://www.precisionvaccinations.com/vaccines/vla2001-covid-19-vaccine |url-status=live |archive-url=https://web.archive.org/web/20210113035455/https://www.precisionvaccinations.com/vaccines/vla2001-covid-19-vaccine |archive-date=13 January 2021 |access-date=11 January 2021 |website=Precision Vaccinations}}{{Unreliable source?|date=June 2021}}{{cite web |date=30 December 2020 |title=Dose Finding Study to Evaluate Safety, Tolerability and Immunogenicity of an Inactivated Adjuvanted Sars-Cov-2 Virus Vaccine Candidate Against Covid-19 in Healthy Adults |url=https://clinicaltrials.gov/ct2/show/NCT04671017 |url-status=live |archive-url=https://web.archive.org/web/20210214223558/https://www.clinicaltrials.gov/ct2/show/NCT04671017 |archive-date=14 February 2021 |access-date=11 January 2021 |publisher=U.S. National Library of Medicine}}

{{anchor|protein subunit}}

Subunit vaccines present one or more antigens without introducing whole pathogen particles. The antigens involved are often protein subunits, but they can be any molecule fragment of the pathogen.{{cite web |title=Module 2 – Subunit vaccines |url=https://vaccine-safety-training.org/subunit-vaccines.html |url-status=live |archive-url=https://web.archive.org/web/20210808211206/https://vaccine-safety-training.org/subunit-vaccines.html |archive-date=8 August 2021 |access-date=17 January 2021 |website=WHO Vaccine Safety Basics}}

The authorized vaccines of this type include the peptide vaccine EpiVacCorona,{{cite web |date=22 September 2020 |title=Study of the Safety, Reactogenicity and Immunogenicity of "EpiVacCorona" Vaccine for the Prevention of COVID-19 (EpiVacCorona) |url=https://clinicaltrials.gov/ct2/show/NCT04527575 |url-status=live |archive-url=https://web.archive.org/web/20210629132034/https://clinicaltrials.gov/ct2/show/NCT04527575 |archive-date=29 June 2021 |access-date=16 November 2020 |publisher=ClinicalTrials.gov |id=NCT04368988}} ZF2001, MVC-COV1901,{{cite web |title=MVC COVID-19 Vaccine Obtains Taiwan EUA Approval |url=https://www.medigenvac.com/public/en/news/detail/83 |archive-url=https://web.archive.org/web/20211127023011/https://www.medigenvac.com/public/en/news/detail/83 |archive-date=27 November 2021 |access-date=7 August 2021 |website=Medigen Vaccine Biologics}} Corbevax,{{cite web |date=28 December 2021 |title=India Clears 2 New Vaccines And Merck's Covid Pill: 10 Points |url=https://www.ndtv.com/india-news/coronavirus-2-more-vaccines-covovax-and-corbevax-and-anti-viral-drug-molnupiravir-cleared-in-india-2675170 |url-status=live |archive-url=https://web.archive.org/web/20211228054125/https://www.ndtv.com/india-news/coronavirus-2-more-vaccines-covovax-and-corbevax-and-anti-viral-drug-molnupiravir-cleared-in-india-2675170 |archive-date=28 December 2021 |access-date=19 January 2022 |website=NDTV.com |vauthors=Achom D}}{{cite web |date=30 December 2021 |title=A COVID Vaccine for All |url=https://www.scientificamerican.com/article/a-covid-vaccine-for-all/ |url-status=live |archive-url=https://web.archive.org/web/20211230172714/https://www.scientificamerican.com/article/a-covid-vaccine-for-all/ |archive-date=30 December 2021 |access-date=19 January 2022 |website=Scientific American |vauthors=Bottazzi ME, Hotez PJ}} the Sanofi–GSK vaccine,{{cite web |date=4 November 2022 |title=VidPrevtyn Beta |url=https://www.ema.europa.eu/en/medicines/human/EPAR/vidprevtyn-beta |access-date=12 November 2022 |website=European Medicines Agency (EMA) |archive-date=11 November 2022 |archive-url=https://web.archive.org/web/20221111174057/https://www.ema.europa.eu/en/medicines/human/EPAR/vidprevtyn-beta |url-status=live }} Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged.{{cite press release |title=EMA recommends approval of VidPrevtyn Beta as a COVID-19 booster vaccine |website=European Medicines Agency (EMA) |date=10 November 2022 |url=https://www.ema.europa.eu/en/news/ema-recommends-approval-vidprevtyn-beta-covid-19-booster-vaccine |access-date=12 November 2022 |archive-date=12 November 2022 |archive-url=https://web.archive.org/web/20221112070932/https://www.ema.europa.eu/en/news/ema-recommends-approval-vidprevtyn-beta-covid-19-booster-vaccine |url-status=live }} Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged. and Soberana 02 (a conjugate vaccine).{{cite web|date=26 April 2021|title=Iran-Cuba vaccine enters phase three clinical trials|url=https://www.tehrantimes.com/news/460275/Iran-Cuba-vaccine-enters-phase-three-clinical-trials|access-date=7 September 2021|website=Tehran Times|archive-date=19 July 2021|archive-url=https://web.archive.org/web/20210719231941/https://www.tehrantimes.com/news/460275/Iran-Cuba-vaccine-enters-phase-three-clinical-trials|url-status=live}} Bimervax (selvacovatein) was approved for use as a booster vaccine in the European Union in March 2023.{{cite web | vauthors=Barrie R | title=Hipra's Covid-19 booster gets EMA nod and enters an uncertain landscape | website=Pharmaceutical Technology | date=31 March 2023 | url=https://www.pharmaceutical-technology.com/news/hipras-covid-19-booster-gets-ema-nod-to-enter-uncertain-landscape/ | access-date=9 April 2023 | archive-date=10 April 2023 | archive-url=https://web.archive.org/web/20230410045239/https://www.pharmaceutical-technology.com/news/hipras-covid-19-booster-gets-ema-nod-to-enter-uncertain-landscape/ | url-status=live }}{{cite web | title=Bimervax EPAR | website=European Medicines Agency | date=5 April 2023 | url=https://www.ema.europa.eu/en/medicines/human/EPAR/bimervax | access-date=9 April 2023 | archive-date=8 April 2023 | archive-url=https://web.archive.org/web/20230408071014/https://www.ema.europa.eu/en/medicines/human/EPAR/bimervax | url-status=live }}{{cite web | title=COVID-19 medicines | website=European Medicines Agency (EMA) | date=14 October 2024 | url=https://www.ema.europa.eu/en/human-regulatory-overview/public-health-threats/coronavirus-disease-covid-19/covid-19-medicines | access-date=14 October 2024}}

The V451 vaccine was in clinical trials that were terminated after it was found that the vaccine may potentially cause incorrect results for subsequent HIV testing.{{cite web |date=3 August 2020 |title=A Study on the Safety, Tolerability and Immune Response of SARS-CoV-2 Sclamp (COVID-19) Vaccine in Healthy Adults |url=https://clinicaltrials.gov/ct2/show/NCT04495933 |url-status=live |archive-url=https://web.archive.org/web/20201011085041/https://clinicaltrials.gov/ct2/show/NCT04495933/ |archive-date=11 October 2020 |access-date=4 August 2020 |website=ClinicalTrials.gov |id=NCT04495933}}{{cite news |title=Australian vaccine trials stopped due to HIV false positives |url=https://www.dw.com/en/australia-ends-local-covid-vaccine-trials-due-to-hiv-false-positives/a-55900847 |website=Deutsche Welle |date=11 December 2020 |access-date=9 January 2023 |archive-date=26 January 2021 |archive-url=https://web.archive.org/web/20210126235229/https://www.dw.com/en/australia-ends-local-covid-vaccine-trials-due-to-hiv-false-positives/a-55900847 |url-status=live }}{{cite news | title=Covid: Australian vaccine abandoned over false HIV response | website=BBC News Online | date=11 December 2020 | url=https://www.bbc.com/news/world-australia-55269381 | access-date=9 April 2023 | archive-date=16 January 2021 | archive-url=https://web.archive.org/web/20210116134101/https://www.bbc.com/news/world-australia-55269381 | url-status=live }}

{{anchor|virus-like particle}}

The authorized vaccines of this type include the Novavax COVID‑19 vaccine.{{cite web |date=30 April 2020 |title=Evaluation of the Safety and Immunogenicity of a SARS-CoV-2 rS (COVID-19) Nanoparticle Vaccine With/Without Matrix-M Adjuvant |url=https://clinicaltrials.gov/ct2/show/NCT04368988 |url-status=live |archive-url=https://web.archive.org/web/20200714224741/https://clinicaltrials.gov/ct2/show/NCT04368988 |archive-date=14 July 2020 |access-date=14 July 2020 |website=ClinicalTrials.gov |id=NCT04368988}}

Additional types of vaccines that are in clinical trials include multiple DNA plasmid vaccines,{{cite web |date=15 December 2020 |title=A prospective, randomized, adaptive, phase I/II clinical study to evaluate the safety and immunogenicity of Novel Corona Virus −2019-nCov vaccine candidate of M/s Cadila Healthcare Limited by intradermal route in healthy subjects |url=http://www.ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=45306 |url-status=live |archive-url=https://web.archive.org/web/20201122022620/http://www.ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=45306 |archive-date=22 November 2020 |publisher=Clinical Trials Registry |location=India |id=CTRI/2020/07/026352}}{{cite web |date=7 April 2020 |title=Safety, Tolerability and Immunogenicity of INO-4800 for COVID-19 in Healthy Volunteers |url=https://clinicaltrials.gov/ct2/show/NCT04336410 |url-status=live |archive-url=https://web.archive.org/web/20201011084843/https://clinicaltrials.gov/ct2/show/NCT04336410/ |archive-date=11 October 2020 |access-date=14 July 2020 |website=ClinicalTrials.gov |id=NCT04336410}}{{cite web |date=16 April 2020 |title=IVI, INOVIO, and KNIH to partner with CEPI in a Phase I/II clinical trial of INOVIO's COVID{{nbhyph}}19 DNA vaccine in South Korea |url=https://www.ivi.int/ivi-inovio-and-knih-to-partner-with-cepi-in-a-phase-i-ii-clinical-trial-of-inovios-covid-19-dna-vaccine-in-south-korea/ |url-status=live |archive-url=https://web.archive.org/web/20200924215700/https://www.ivi.int/ivi-inovio-and-knih-to-partner-with-cepi-in-a-phase-i-ii-clinical-trial-of-inovios-covid-19-dna-vaccine-in-south-korea/ |archive-date=24 September 2020 |access-date=23 April 2020 |publisher=International Vaccine Institute}}{{cite web |date=9 July 2020 |title=Study of COVID-19 DNA Vaccine (AG0301-COVID19) |url=https://clinicaltrials.gov/ct2/show/NCT04463472 |url-status=live |archive-url=https://web.archive.org/web/20201011084854/https://clinicaltrials.gov/ct2/show/NCT04463472/ |archive-date=11 October 2020 |access-date=14 July 2020 |website=ClinicalTrials.gov |id=NCT04463472}}{{cite web |date=24 June 2020 |title=Safety and Immunogenicity Study of GX-19, a COVID-19 Preventive DNA Vaccine in Healthy Adults |url=https://clinicaltrials.gov/ct2/show/NCT04445389 |url-status=live |archive-url=https://web.archive.org/web/20201011084931/https://clinicaltrials.gov/ct2/show/NCT04445389/ |archive-date=11 October 2020 |access-date=14 July 2020 |website=ClinicalTrials.gov |id=NCT04445389}}{{cite news |date=19 June 2020 |title=S. Korea's Genexine begins human trial of coronavirus vaccine |publisher=Reuters |url=https://www.reuters.com/article/health-coronavirus-genexine-vaccine-idUSL4N2DW1T3 |url-status=live |access-date=25 June 2020 |archive-url=https://web.archive.org/web/20201011084934/https://www.reuters.com/article/health-coronavirus-genexine-vaccine-idUSL4N2DW1T3/ |archive-date=11 October 2020}} at least two lentivirus vector vaccines,{{cite journal |vauthors=Chang LJ |date=March 2020 |title=Safety and Immunity of Covid-19 aAPC Vaccine |url=https://clinicaltrials.gov/ct2/show/NCT04299724 |url-status=live |id=NCT04299724 |archive-url=https://web.archive.org/web/20201011084913/https://clinicaltrials.gov/ct2/show/NCT04299724/ |archive-date=11 October 2020 |access-date=14 July 2020 |website=ClinicalTrials.gov}}{{cite journal |date=February 2020 |title=Immunity and Safety of Covid-19 Synthetic Minigene Vaccine |url=https://clinicaltrials.gov/ct2/show/NCT04276896 |url-status=live |id=NCT04276896 |archive-url=https://web.archive.org/web/20201011084923/https://clinicaltrials.gov/ct2/show/NCT04276896/ |archive-date=11 October 2020 |access-date=14 July 2020 |website=ClinicalTrials.gov}} a conjugate vaccine, and a vesicular stomatitis virus displaying the SARS‑CoV‑2 spike protein.{{cite journal |date=November 2020 |title=A Phase I/II Randomized, Multi-Center, Placebo-Controlled, Dose-Escalation Study to Evaluate the Safety, Immunogenicity and Potential Efficacy of an rVSV-SARS-CoV-2-S Vaccine (IIBR-100) in Adults |url=https://clinicaltrials.gov/ct2/show/NCT04608305 |url-status=live |id=NCT04608305 |archive-url=https://web.archive.org/web/20210503103642/https://clinicaltrials.gov/ct2/show/NCT04608305 |archive-date=3 May 2021 |access-date=2 January 2021 |website=ClinicalTrials.gov}}

Scientists investigated whether existing vaccines for unrelated conditions could prime the immune system and lessen the severity of COVID{{nbhyph}}19 infections.{{cite news |date=11 June 2020 |title=Can old vaccines from science's medicine cabinet ward off coronavirus? |newspaper=The Washington Post |url=https://www.washingtonpost.com/health/2020/06/11/can-old-vaccines-sciences-medicine-cabinet-ward-off-coronavirus/ |url-status=live |access-date=31 December 2020 |archive-url=https://web.archive.org/web/20200611225045/https://www.washingtonpost.com/health/2020/06/11/can-old-vaccines-sciences-medicine-cabinet-ward-off-coronavirus/ |archive-date=11 June 2020 |issn=0190-8286 |vauthors=Johnson CY, Mufson S}} There is experimental evidence that the BCG vaccine for tuberculosis has non-specific effects on the immune system, but there is no evidence that this vaccine is effective against COVID{{nbhyph}}19.{{cite web |date=12 April 2020 |title=Bacille Calmette-Guérin (BCG) vaccination and COVID-19 |url=https://www.who.int/news-room/commentaries/detail/bacille-calmette-gu%C3%A9rin-(bcg)-vaccination-and-covid-19 |url-status=live |archive-url=https://web.archive.org/web/20200430121126/https://www.who.int/news-room/commentaries/detail/bacille-calmette-gu%C3%A9rin-(bcg)-vaccination-and-covid-19 |archive-date=30 April 2020 |access-date=1 May 2020 |work=World Health Organization (WHO)}}

{{Main|List of COVID-19 vaccine authorizations}}

{{mw-datatable}}{{sticky header}}

Most coronavirus vaccines are administered by intramuscular injection, with further vaccine delivery methods being studied for future coronavirus vaccines.

Intranasal vaccines target mucosal immunity in the nasal mucosa, which is a portal for viral entry into the body.{{cite journal | vauthors = Mudgal R, Nehul S, Tomar S | title = Prospects for mucosal vaccine: shutting the door on SARS-CoV-2 | journal = Human Vaccines & Immunotherapeutics | volume = 16 | issue = 12 | pages = 2921–2931 | date = December 2020 | pmid = 32931361 | pmc = 7544966 | doi = 10.1080/21645515.2020.1805992 }}{{cite book | vauthors = Rhee JH | title=Mucosal Vaccines | chapter=Current and New Approaches for Mucosal Vaccine Delivery | publisher=Elsevier | year=2020 | pmid= | pmc=7149853 | doi=10.1016/b978-0-12-811924-2.00019-5 | pages=325–356| isbn=9780128119242 }} These vaccines are designed to stimulate nasal immune factors, such as IgA. In addition to inhibiting the virus, nasal vaccines provide ease of administration because no needles (or needle phobia) are involved.{{cite web |title=Live Attenuated Influenza Vaccine [LAIV] (The Nasal Spray Flu Vaccine) |url=https://www.cdc.gov/flu/prevent/nasalspray.htm |publisher=U.S. Centers for Disease Control and Prevention (CDC) |access-date=8 September 2021 |date=3 August 2021 |archive-date=14 October 2019 |archive-url=https://web.archive.org/web/20191014221155/https://www.cdc.gov/flu/prevent/nasalspray.htm |url-status=live }}

A variety of intranasal COVID{{nbhyph}}19 vaccines are undergoing clinical trials. The first authorised intranasal vaccine was Razi Cov Pars in Iran at the end of October 2021.{{cite news |title=Two homegrown vaccines receive emergency use license |url=https://www.tehrantimes.com/news/466570/Two-homegrown-vaccines-receive-emergency-use-license |access-date=5 June 2024 |work=Tehran Times |date=1 November 2021 }} The first viral component of Sputnik V vaccine was authorised in Russia as Sputnik Nasal in April 2022.{{cite news | vauthors = Maksimova K |title=A scientist at the Gamaleya Center spoke about the benefits of a nasal vaccine against coronavirus |url=https://sibmeda.ru/news/meditsinskie-innovatsii/uchyenyy-tsentra-gamalei-rasskazal-o-preimushchestvakh-nazalnoy-vaktsiny-ot-koronavirusa/ |access-date=5 June 2024 |work=sibmeda.ru}} In September 2022, India and China approved two nasal COVID{{nbhyph}}19 vaccines (iNCOVACC and Convidecia), which may (as boosters){{cite news |title=Two inhaled covid vaccines have been approved—but we don't know yet how good they are |url=https://www.technologyreview.com/2022/09/08/1059107/two-inhaled-covid-vaccines-approved/ |access-date=21 October 2022 |work=MIT Technology Review |archive-date=21 October 2022 |archive-url=https://web.archive.org/web/20221021140344/https://www.technologyreview.com/2022/09/08/1059107/two-inhaled-covid-vaccines-approved/ |url-status=live }} also reduce transmission{{cite journal | vauthors = Dhama K, Dhawan M, Tiwari R, Emran TB, Mitra S, Rabaan AA, Alhumaid S, Alawi ZA, Al Mutair A | title = COVID-19 intranasal vaccines: current progress, advantages, prospects, and challenges | journal = Human Vaccines & Immunotherapeutics | volume = 18 | issue = 5 | pages = 2045853 | date = November 2022 | pmid = 35258416 | pmc = 8935456 | doi = 10.1080/21645515.2022.2045853 }} (potentially via sterilizing immunity).{{cite journal | vauthors = Waltz E | title = China and India approve nasal COVID vaccines - are they a game changer? | journal = Nature | volume = 609 | issue = 7927 | pages = 450 | date = September 2022 | pmid = 36071228 | doi = 10.1038/d41586-022-02851-0 | s2cid = 252121594 | bibcode = 2022Natur.609..450W | title-link = doi | doi-access = free }} In December 2022, China approved a second intranasal vaccine as a booster, trade name Pneucolin.{{cite web|url=http://www.nhc.gov.cn/xcs/zhengcwj/202212/acd8ba68d934488983909e81642dc337.shtml|title=关于印发新冠病毒疫苗第二剂次加强免疫接种实施方案的通知|publisher=National Health Commission|date=14 December 2022|language=zh|accessdate=14 December 2022}}

Aivita Biomedical is developing an experimental autologous dendritic cell COVID{{nbhyph}}19 vaccine kit where the vaccine is prepared and incubated at the point-of-care using cells from the intended recipient. The vaccine is undergoing small phase I and phase II clinical studies.{{cite journal | vauthors = Nistor GI, Dillman RO, Robles RM, Langford JL, Poole AJ, Sofro MA, Nency YM, Jonny J, Yana ML, Karyana M, Lestari ES, Triwardhani R, Mujahidah M, Sari RK, Soetojo NA, Wibisono D, Tjen D, Ikrar T, Sarkissian G, Winarta H, Putranto TA, Keirstead HS | title = A personal COVID-19 dendritic cell vaccine made at point-of-care: Feasibility, safety, and antigen-specific cellular immune responses | journal = Human Vaccines & Immunotherapeutics | pages = 2100189 | date = August 2022 | pmid = 36018753 | doi = 10.1080/21645515.2022.2100189 | volume = 18 | issue = 6 | pmc = 9746383 | title-link = doi | doi-access = free }}{{cite journal | title=Dendritic Cell Vaccine, AV-COVID-19, to Prevent COVID-19 Infection | website=ClinicalTrials.gov | date=30 December 2020 | url=https://clinicaltrials.gov/ct2/show/NCT04690387 | access-date=5 September 2022 | archive-date=13 May 2022 | archive-url=https://web.archive.org/web/20220513201453/https://www.clinicaltrials.gov/ct2/show/NCT04690387 | url-status=live }}{{cite journal | title=Preventive Dendritic Cell Vaccine, AV-COVID-19, in Subjects Not Actively Infected With COVID-19 | website=ClinicalTrials.gov | date=16 August 2021 | url=https://clinicaltrials.gov/ct2/show/NCT05007496 | access-date=5 September 2022 | archive-date=18 June 2022 | archive-url=https://web.archive.org/web/20220618005430/https://clinicaltrials.gov/ct2/show/NCT05007496 | url-status=live }}

{{Main|Universal coronavirus vaccine}}

A universal coronavirus vaccine would be effective against all coronaviruses and possibly other viruses.{{cite web | vauthors = Mullin E |date=9 June 2021 |title=A 'Universal' Coronavirus Vaccine to Prevent the Next Pandemic |url=https://www.scientificamerican.com/podcast/episode/a-universal-coronavirus-vaccine-to-prevent-the-next-pandemic1/ |url-status=live |archive-url=https://web.archive.org/web/20211220060024/https://www.scientificamerican.com/podcast/episode/a-universal-coronavirus-vaccine-to-prevent-the-next-pandemic1/ |archive-date=20 December 2021 |access-date=20 December 2021 |website=Scientific American }}{{cite web | vauthors = Joi P |date=13 July 2021 |title=Could a universal coronavirus vaccine soon be a reality? |url=https://www.gavi.org/vaccineswork/could-universal-coronavirus-vaccine-soon-be-reality |url-status=live |archive-url=https://web.archive.org/web/20211220054527/https://www.gavi.org/vaccineswork/could-universal-coronavirus-vaccine-soon-be-reality |archive-date=20 December 2021 |access-date=20 December 2021 |website=GAVI }} The concept was publicly endorsed by NIAID director Anthony Fauci, virologist Jeffery K. Taubenberger, and David M. Morens.{{cite web | vauthors = Bush E |date= 15 December 2021 |title=Fauci pushes for universal coronavirus vaccine |url= https://www.nbcnews.com/science/science-news/fauci-pushes-universal-coronavirus-vaccine-rcna8877 |url-status=live |archive-url=https://web.archive.org/web/20211220054522/https://www.nbcnews.com/science/science-news/fauci-pushes-universal-coronavirus-vaccine-rcna8877 |archive-date=20 December 2021 |access-date=20 December 2021 |website=NBC News }} In March 2022, the White House released the "National COVID{{nbhyph}}19 Preparedness Plan", which recommended accelerating the development of a universal coronavirus vaccine.{{cite web |date=March 2022 |title=National COVID-19 Preparedness Plan |url=https://bidenwhitehouse.archives.gov/wp-content/uploads/2022/03/NAT-COVID-19-PREPAREDNESS-PLAN.pdf |archive-url=https://web.archive.org/web/20220326181157/https://www.whitehouse.gov/wp-content/uploads/2022/03/NAT-COVID-19-PREPAREDNESS-PLAN.pdf |archive-date=26 March 2022 |access-date=29 March 2022 |publisher=The White House |url-status=live |pages=9, 21, 29}}

One attempt at such a vaccine is being developed at the Walter Reed Army Institute of Research. It uses a spike ferritin-based nanoparticle (SpFN). This vaccine began a Phase I clinical trial in April 2022.{{cite news |date=5 April 2022 |title=Phase 1 Clinical Trial of WRAIR-developed COVID-19 Vaccine Begins |url=https://www.wrair.army.mil/node/636 |access-date=11 July 2022 |archive-date=11 July 2022 |archive-url=https://web.archive.org/web/20220711041214/https://www.wrair.army.mil/node/636 |url-status=dead }} Results of this trial were published in May 2024.{{cite journal | vauthors = Ober Shepherd BL, Scott PT, Hutter JN, Lee C, McCauley MD, Guzman I, Bryant C, McGuire S, Kennedy J, Chen WH, Hajduczki A, Mdluli T, Valencia-Ruiz A, Amare MF, Matyas GR, Rao M, Rolland M, Mascola JR, De Rosa SC, McElrath MJ, Montefiori DC, Serebryannyy L, McDermott AB, Peel SA, Collins ND, Joyce MG, Robb ML, Michael NL, Vasan S, Modjarrad K, Gebrehana B, Greenleaf ME, Hamer MJ, Jansen NK, Jing X, Kagai J, Kourbanova K, Koren MA, Martin ML, Wuertz KM, Regules JA, Sanborn AD, Wallace D, Zhu L, Gromowski GD, Corbitt C, Darden JM, Dussupt V, Golub ES, Headley JA, Jarral UM, King J, Krebs SJ, Lay J, Lilly R, Lynch J, Martinez EJ, Mayer SV, McGeehon S, Lee H, Schech S, Tadesse M, Thomas PV, Romem Y, Zografos E, Lin BC, Narpala SR, Wang L, Doria-Rose NA, Carroll RE, Eaton A, Badraslioglu ED, Koontz JM, Nwaeze UE, Dawson P, Noll AJ, Orndahl CM, Bray A, Carrion R, Patterson J, Kulkarni V, Hallam C, Gonzalez O, Gazi M | collaboration = EID-030 Study Group | title = SARS-CoV-2 recombinant spike ferritin nanoparticle vaccine adjuvanted with Army Liposome Formulation containing monophosphoryl lipid A and QS-21: a phase 1, randomised, double-blind, placebo-controlled, first-in-human clinical trial | journal = The Lancet. Microbe | volume = 5 | issue = 6 | pages = e581–e593 | date = June 2024 | pmid = 38761816 | doi = 10.1016/S2666-5247(23)00410-X | pmc = 11192176 | pmc-embargo-date = 1 June 2025 }} Other universal vaccines that have entered clinical trial include OVX033 (France),{{cite web |title=First-in-human Study to Evaluate the Safety and Immunogenicity of Three Dose Levels of the OVX033 Coronavirus Vaccine Candidate in Healthy Volunteers |url=https://clinicaltrials.gov/study/NCT06128382 |website=clinicaltrials.gov |access-date=30 August 2024}} PanCov (France),{{cite journal |title=Safety and Immunogenicity of a Sub-unit Protein CD40.RBDv Bivalent COVID-19 Vaccine, Adjuvanted or Not, as a Booster in Volunteers |url=https://clinicaltrials.gov/study/NCT06255626 |website=clinicaltrials.gov |date=11 June 2024 |access-date=30 August 2024}} pEVAC-PS (UK),{{cite web |title=Phase I vaccine study of pEVAC-PS coronavirus vaccine |url=https://www.isrctn.com/ISRCTN87813400 |website=www.isrctn.com |access-date=30 August 2024}} and VBI-2902 (Canada).{{cite journal |title=Safety, Tolerability, and Immunogenicity of Trivalent Coronavirus Vaccine Candidate VBI-2901a |url=https://clinicaltrials.gov/study/NCT05548439 |website=clinicaltrials.gov |date=13 February 2023 |publisher=National Institutes of Health |access-date=30 August 2024}}

Another strategy is to attach vaccine fragments from multiple strains to a nanoparticle scaffold. One theory is that a broader range of strains can be vaccinated against by targeting the receptor-binding domain, rather than the whole spike protein.{{cite web | vauthors = Haridy R |date=7 July 2022 |title=Another universal coronavirus vaccine readies for human trials |url=https://newatlas.com/science/universal-coronavirus-vaccine-mosaic-nanoparticle-human-trials-caltech/ |access-date=11 July 2022 |website=New Atlas |archive-date=11 July 2022 |archive-url=https://web.archive.org/web/20220711024151/https://newatlas.com/science/universal-coronavirus-vaccine-mosaic-nanoparticle-human-trials-caltech/ |url-status=live }}

{{As of|2020|September}}, eleven of the vaccine candidates in clinical development use adjuvants to enhance immunogenicity. An immunological adjuvant is a substance formulated with a vaccine to elevate the immune response to an antigen, such as the COVID{{nbhyph}}19 virus or influenza virus.{{cite journal |vauthors=Tregoning JS, Russell RF, Kinnear E |date=March 2018 |title=Adjuvanted influenza vaccines |journal=Human Vaccines & Immunotherapeutics |volume=14 |issue=3 |pages=550–564 |doi=10.1080/21645515.2017.1415684 |pmc=5861793 |pmid=29232151}} Specifically, an adjuvant may be used in formulating a COVID{{nbhyph}}19 vaccine candidate to boost its immunogenicity and efficacy to reduce or prevent COVID{{nbhyph}}19 infection in vaccinated individuals.{{cite journal |vauthors=Wang J, Peng Y, Xu H, Cui Z, Williams RO |date=August 2020 |title=The COVID-19 Vaccine Race: Challenges and Opportunities in Vaccine Formulation |journal=AAPS PharmSciTech |volume=21 |issue=6 |pages=225 |doi=10.1208/s12249-020-01744-7 |pmc=7405756 |pmid=32761294}} Adjuvants used in COVID{{nbhyph}}19 vaccine formulation may be particularly effective for technologies using the inactivated COVID{{nbhyph}}19 virus and recombinant protein-based or vector-based vaccines. Aluminum salts, known as "alum", were the first adjuvant used for licensed vaccines and are the adjuvant of choice in some 80% of adjuvanted vaccines. The alum adjuvant initiates diverse molecular and cellular mechanisms to enhance immunogenicity, including the release of proinflammatory cytokines.

In June 2024, the US Food and Drug Administration advised the manufacturers of the licensed and authorized COVID-19 vaccines that the COVID-19 vaccines (2024-2025 Formula) for use in the United States beginning in fall 2024 should be monovalent JN.1 vaccines.{{cite web | title=Updated COVID-19 Vaccines for Use in the United States Beginning in Fall 2024 | website=U.S. Food and Drug Administration (FDA) | date=5 June 2024 | url=https://www.fda.gov/vaccines-blood-biologics/updated-covid-19-vaccines-use-united-states-beginning-fall-2024 | access-date=19 June 2024}} {{PD-notice}}

As of May 2025, the World Health Organization recommends that monovalent JN.1 or KP.2 vaccines remain appropriate vaccine antigens and that monovalent LP.8.1 is a suitable alternative vaccine antigen.{{cite press release | title=Statement on the antigen composition of COVID-19 vaccines | website=World Health Organization (WHO) | date=15 May 2025 | url=https://www.who.int/news/item/15-05-2025-statement-on-the-antigen-composition-of-covid-19-vaccines | access-date=16 May 2025}} The European Medicines Agency recommends updating COVID-19 vaccines to target LP.8.1 for the 2025/2026 vaccination campaign.{{cite press release | title=ETF recommends updating COVID-19 vaccines to target new LP.8.1 variant | website=European Medicines Agency (EMA) | date=16 May 2025 | url=https://www.ema.europa.eu/en/news/etf-recommends-updating-covid-19-vaccines-target-new-lp81-variant | access-date=16 May 2025}}

{{Main|History of COVID-19 vaccine development}}

Since January 2020, vaccine development has been expedited via unprecedented collaboration in the multinational pharmaceutical industry and between governments.{{cite journal | vauthors=Le TT, Cramer JP, Chen R, Mayhew S |date=October 2020 |title=Evolution of the COVID-19 vaccine development landscape |journal=Nature Reviews. Drug Discovery |volume=19 |issue=10 |pages=667–68 |doi=10.1038/d41573-020-00151-8 |pmid=32887942 | title-link = doi | doi-access = free |s2cid=221503034}}

Multiple steps along the entire development path are evaluated, including:{{cite journal | vauthors=Simpson S, Kaufmann MC, Glozman V, Chakrabarti A |date=May 2020 |title=Disease X: accelerating the development of medical countermeasures for the next pandemic |journal=The Lancet. Infectious Diseases |volume=20 |issue=5 |pages=e108–15 |doi=10.1016/S1473-3099(20)30123-7 |pmc=7158580 |pmid=32197097 | title-link = doi | doi-access = free }}

• the level of acceptable toxicity of the vaccine (its safety),
• targeting vulnerable populations,
• the need for vaccine efficacy breakthroughs,
• the duration of vaccination protection,
• special delivery systems (such as oral or nasal, rather than by injection),
• dose regimen,
• stability and storage characteristics,
• emergency use authorization before formal licensing,
• optimal manufacturing for scaling to billions of doses, and
• dissemination of the licensed vaccine.

There have been several unique challenges with COVID{{nbhyph}}19 vaccine development.

Timelines for conducting clinical research{{snd}}normally a sequential process requiring years{{snd}}are being compressed into safety, efficacy, and dosing trials running simultaneously over months, potentially compromising safety assurance.{{cite news |date=2 May 2020 |title=With Pressure Growing, Global Race for a Vaccine Intensifies |work=The New York Times |url=https://www.nytimes.com/2020/05/02/us/politics/vaccines-coronavirus-research.html |url-status=live |access-date=2 May 2020 |archive-url=https://web.archive.org/web/20200511003506/https://www.nytimes.com/2020/05/02/us/politics/vaccines-coronavirus-research.html |archive-date=11 May 2020 |issn=0362-4331 |vauthors=Sanger DE, Kirkpatrick DD, Zimmer C, Thomas K, Wee SL}}{{cite news | date=27 April 2020 |title=Special Report: Countries, companies risk billions in race for coronavirus vaccine |publisher=Reuters |url=https://www.reuters.com/article/health-coronavirus-vaccine-idUSL2N2CF0JG |url-status=live |access-date=2 May 2020 |archive-url=https://web.archive.org/web/20200515031817/https://www.reuters.com/article/health-coronavirus-vaccine-idUSL2N2CF0JG |archive-date=15 May 2020 |vauthors=Steenhuysen J, Eisler P, Martell A, Nebehay S}} For example, Chinese vaccine developers and the Chinese Center for Disease Control and Prevention began their efforts in January 2020,{{cite news | date=26 January 2020 |title=Chinese scientists race to develop vaccine as coronavirus death toll jumps |work=South China Morning Post |url=https://www.scmp.com/news/china/society/article/3047676/number-coronavirus-cases-china-doubles-spread-rate-accelerates |url-status=live |access-date=28 January 2020 |archive-url=https://web.archive.org/web/20200126073453/https://www.scmp.com/news/china/society/article/3047676/number-coronavirus-cases-china-doubles-spread-rate-accelerates |archive-date=26 January 2020 |vauthors=Jeong-ho L, Zheng W, Zhou L}} and by March they were pursuing numerous candidates on short timelines.{{cite news | date=4 May 2020 |title=China's coronavirus vaccine drive empowers a troubled industry |work=The New York Times |url=https://www.nytimes.com/2020/05/04/business/coronavirus-china-vaccine.html |url-status=live |access-date=4 May 2020 |archive-url=https://web.archive.org/web/20200504175312/https://www.nytimes.com/2020/05/04/business/coronavirus-china-vaccine.html |archive-date=4 May 2020 |issn=0362-4331 |vauthors=Wee SL}}

The rapid development and urgency of producing a vaccine for the COVID{{nbhyph}}19 pandemic were expected to increase the risks and failure rate of delivering a safe, effective vaccine.{{cite journal | vauthors=Thanh Le T, Andreadakis Z, Kumar A, Gómez Román R, Tollefsen S, Saville M, Mayhew S |date=May 2020 |title=The COVID-19 vaccine development landscape |journal=Nature Reviews. Drug Discovery |volume=19 |issue=5 |pages=305–06 |doi=10.1038/d41573-020-00073-5 |pmid=32273591 | title-link = doi | doi-access = free }}{{cite journal | vauthors=Diamond MS, Pierson TC |date=May 2020 |title=The Challenges of Vaccine Development against a New Virus during a Pandemic |journal=Cell Host & Microbe |volume=27 |issue=5 |pages=699–703 |doi=10.1016/j.chom.2020.04.021 |pmc=7219397 |pmid=32407708}}{{cite journal | vauthors=Thorp HH |date=March 2020 |title=Underpromise, overdeliver |journal=Science |volume=367 |issue=6485 |pages=1405 |bibcode=2020Sci...367.1405T |doi=10.1126/science.abb8492 |pmid=32205459 | title-link = doi | doi-access = free |s2cid=214628067 }} Additionally, research at universities is obstructed by physical distancing and the closing of laboratories.{{cite news | date=20 April 2020 |title=COVID-19 vaccine researchers say pandemic lockdown placing many serious obstacles to their work |work=National Post |url=https://nationalpost.com/news/covid-19-vaccine-researchers-say-pandemic-lockdown-placing-many-serious-obstacles-to-their-work |access-date=3 May 2020 |vauthors=Blackwell T}}{{cite web | vauthors = Chen J |date=4 May 2020|title=Covid-19 has shuttered labs. It could put a generation of researchers at risk|url=https://www.statnews.com/2020/05/04/coronavirus-lab-shutdowns-impact-on-scientists-research-delays/|archive-url=https://web.archive.org/web/20200506072301/https://www.statnews.com/2020/05/04/coronavirus-lab-shutdowns-impact-on-scientists-research-delays/|archive-date=6 May 2020|url-status=live|access-date=4 May 2020|work=Stat}}

Vaccines must progress through several phases of clinical trials to test for safety, immunogenicity, effectiveness, dose levels, and adverse effects of the candidate vaccine.{{cite web |title=Vaccine Safety – Vaccines|url=https://www.vaccines.gov/basics/safety|archive-url=https://web.archive.org/web/20200422073442/https://www.vaccines.gov/basics/safety|archive-date=22 April 2020|url-status=live|access-date=13 April 2020|publisher=US Department of Health and Human Services}}{{cite web |date=4 January 2018|title=The drug development process|url=https://www.fda.gov/patients/learn-about-drug-and-device-approvals/drug-development-process|archive-url=https://web.archive.org/web/20200222182002/https://www.fda.gov/patients/learn-about-drug-and-device-approvals/drug-development-process|archive-date=22 February 2020|url-status=live|access-date=12 April 2020|publisher=U.S. Food and Drug Administration (FDA)}} Vaccine developers have to invest resources internationally to find enough participants for Phase{{spaces}}II–III clinical trials when the virus has proved to be a "moving target" of changing transmission rates across and within countries, forcing companies to compete for trial participants.{{cite journal | vauthors=Cohen J |date=June 2020 |title=Pandemic vaccines are about to face the real test |journal=Science |volume=368 |issue=6497 |pages=1295–96 |bibcode=2020Sci...368.1295C |doi=10.1126/science.368.6497.1295 |pmid=32554572 | title-link = doi | doi-access = free |s2cid=219911109 }}

Clinical trial organizers may also encounter people unwilling to be vaccinated due to vaccine hesitancy{{cite journal | vauthors=Dubé E, Laberge C, Guay M, Bramadat P, Roy R, Bettinger J |date=August 2013 |title=Vaccine hesitancy: an overview |journal=Human Vaccines & Immunotherapeutics |volume=9 |issue=8 |pages=1763–73 |doi=10.4161/hv.24657 |pmc=3906279 |pmid=23584253}} or disbelief in the science of the vaccine technology and its ability to prevent infection.{{cite news | date=18 June 2020 |title=Fauci warns of 'anti-science bias' being a problem in US |work=CNN|url=https://www.cnn.com/2020/06/18/politics/anthony-fauci-coronavirus-anti-science-bias/index.html |url-status=live |access-date=21 June 2020 |archive-url=https://web.archive.org/web/20200621003117/https://www.cnn.com/2020/06/18/politics/anthony-fauci-coronavirus-anti-science-bias/index.html |archive-date=21 June 2020 |vauthors=Howard J, Stracqualursi V}} As new vaccines are developed during the COVID{{nbhyph}}19 pandemic, licensure of COVID{{nbhyph}}19 vaccine candidates requires submission of a full dossier of information on development and manufacturing quality.{{cite web |year=2020|title=Vaccines: The Emergency Authorisation Procedure|url=https://www.ema.europa.eu/en/authorisation-procedures|archive-url=https://web.archive.org/web/20200924065451/https://www.ema.europa.eu/en/authorisation-procedures|archive-date=24 September 2020|url-status=live|access-date=21 August 2020|publisher=European Medicines Agency (EMA)}}{{cite web|vauthors=Byrne J|date=19 October 2020|title=Moderna COVID-19 vaccine under rolling review process in Canada, EU|url=https://www.biopharma-reporter.com/Article/2020/10/19/Moderna-COVID-19-vaccine-under-rolling-review-process-in-Canada-EU|access-date=25 November 2020|publisher=BioPharma-Reporter.com, William Reed Business Media Ltd|archive-date=25 February 2021|archive-url=https://web.archive.org/web/20210225075656/https://www.biopharma-reporter.com/Article/2020/10/19/Moderna-COVID-19-vaccine-under-rolling-review-process-in-Canada-EU|url-status=live}}{{cite news |date=20 November 2020 |title=Pfizer files for emergency use of coronavirus vaccine in U.S. – what about in Canada? |work=Global News |url=https://globalnews.ca/news/7474273/pfizer-emergency-use-coronavirus-vaccine-canada/ |access-date=25 November 2020 |vauthors=Dangerfield K |archive-date=25 January 2021 |archive-url=https://web.archive.org/web/20210125183616/https://globalnews.ca/news/7474273/pfizer-emergency-use-coronavirus-vaccine-canada/ |url-status=live }}

Internationally, the Access to COVID‑19 Tools Accelerator is a G20 and World Health Organization (WHO) initiative announced in April 2020.{{cite news |date=25 April 2020 |title=G20 launches initiative for health tools needed to combat the coronavirus |work=The Globe and Mail |url=https://www.theglobeandmail.com/world/article-g20-launches-initiative-for-health-tools-needed-to-combat-the-2/ |access-date=1 February 2021 |archive-date=27 April 2020 |archive-url=https://web.archive.org/web/20200427134921/https://www.theglobeandmail.com/world/article-g20-launches-initiative-for-health-tools-needed-to-combat-the-2/ |url-status=live }}{{cite web|date=24 April 2020|title=Access to COVID-19 Tools (ACT) Accelerator|publisher=World Health Organization (WHO)|url=https://www.who.int/docs/default-source/coronaviruse/access-to-covid-19-tools-(act)-accelerator-call-to-action-24april2020.pdf|access-date=1 February 2021|archive-date=25 April 2020|archive-url=https://web.archive.org/web/20200425194644/https://www.who.int/docs/default-source/coronaviruse/access-to-covid-19-tools-(act)-accelerator-call-to-action-24april2020.pdf|url-status=live}} It is a cross-discipline support structure to enable partners to share resources and knowledge. It comprises four pillars, each managed by two to three collaborating partners: Vaccines (also called "COVAX"), Diagnostics, Therapeutics, and Health Systems Connector.{{cite web|year=2020|title=The ACT-Accelerator: frequently asked questions (FAQ)|url=https://www.who.int/initiatives/act-accelerator/faq|access-date=16 December 2020|publisher=World Health Organization (WHO)|archive-date=4 May 2021|archive-url=https://web.archive.org/web/20210504125946/https://www.who.int/initiatives/act-accelerator/faq|url-status=live}} The WHO's April 2020 "R&D Blueprint (for the) novel Coronavirus" documented a "large, international, multi-site, individually randomized controlled clinical trial" to allow "the concurrent evaluation of the benefits and risks of each promising candidate vaccine within 3–6 months of it being made available for the trial." The WHO vaccine coalition will prioritize which vaccines should go into Phase{{spaces}}II and{{spaces}}III clinical trials and determine harmonized Phase{{spaces}}III protocols for all vaccines achieving the pivotal trial stage.{{cite web |date=27 April 2020|title=Update on WHO Solidarity Trial – Accelerating a safe and effective COVID-19 vaccine|url=https://www.who.int/emergencies/diseases/novel-coronavirus-2019/global-research-on-novel-coronavirus-2019-ncov/solidarity-trial-accelerating-a-safe-and-effective-covid-19-vaccine|archive-url=https://web.archive.org/web/20200430185550/https://www.who.int/emergencies/diseases/novel-coronavirus-2019/global-research-on-novel-coronavirus-2019-ncov/solidarity-trial-accelerating-a-safe-and-effective-covid-19-vaccine|archive-date=30 April 2020|url-status=live|access-date=2 May 2020|publisher=World Health Organization (WHO)|quote=It is vital that we evaluate as many vaccines as possible as we cannot predict how many will turn out to be viable. To increase the chances of success (given the high level of attrition during vaccine development), we must test all candidate vaccines until they fail. [The] WHO is working to ensure that all of them have the chance of being tested at the initial stage of development. The results for the efficacy of each vaccine are expected within three to six months, and this evidence, combined with data on safety, will inform decisions about whether it can be used on a wider scale.}}

National governments have also been involved in vaccine development. Canada announced funding for 96 projects for the development and production of vaccines at Canadian companies and universities, with plans to establish a "vaccine bank" that could be used if another coronavirus outbreak occurs,{{cite news | date=23 March 2020 |title=Canada to spend $192M on developing COVID-19 vaccine |work=Global News |url=https://globalnews.ca/news/6717883/coronavirus-canada-vaccine-spending/ |url-status=live |access-date=24 March 2020 |archive-url=https://web.archive.org/web/20200409200638/https://globalnews.ca/news/6717883/coronavirus-canada-vaccine-spending/ |archive-date=9 April 2020 |vauthors=Abedi M}} support clinical trials, and develop manufacturing and supply chains for vaccines.{{cite web |date=23 April 2020|title=Government of Canada's research response to COVID-19|url=https://www.canada.ca/en/public-health/services/publications/diseases-conditions/covid-19-government-canada-research-response.html|archive-url=https://web.archive.org/web/20200513135919/https://www.canada.ca/en/public-health/services/publications/diseases-conditions/covid-19-government-canada-research-response.html|archive-date=13 May 2020|url-status=live|access-date=4 May 2020|publisher=Government of Canada}}

China provided low-rate loans to one vaccine developer through its central bank and "quickly made land available for the company" to build production plants. Three Chinese vaccine companies and research institutes are supported by the government for financing research, conducting clinical trials, and manufacturing.{{cite news | date=2 May 2020 |title=US and China unleash wallets in race for coronavirus vaccine |work=Nikkei Asian Review |url=https://asia.nikkei.com/Spotlight/Coronavirus/US-and-China-unleash-wallets-in-race-for-coronavirus-vaccine |url-status=live |access-date=3 May 2020 |archive-url=https://web.archive.org/web/20200510111134/https://asia.nikkei.com/Spotlight/Coronavirus/US-and-China-unleash-wallets-in-race-for-coronavirus-vaccine |archive-date=10 May 2020 |vauthors=Takada N, Satake M}}

The United Kingdom government formed a COVID{{nbhyph}}19 vaccine task force in April 2020 to stimulate local efforts for accelerated development of a vaccine through collaborations between industries, universities, and government agencies. The UK's Vaccine Taskforce contributed to every phase of development, from research to manufacturing.{{cite web | vauthors = Morriss E |date=22 April 2020|title=Government launches coronavirus vaccine taskforce as human clinical trials start|url=https://pharmafield.co.uk/pharma_news/government-launches-coronavirus-vaccine-taskforce-as-human-clinical-trials-start/|archive-url=https://web.archive.org/web/20200626021103/https://pharmafield.co.uk/pharma_news/government-launches-coronavirus-vaccine-taskforce-as-human-clinical-trials-start/|archive-date=26 June 2020|url-status=live|access-date=3 May 2020|publisher=Pharmafield}}

In the United States, the Biomedical Advanced Research and Development Authority (BARDA), a federal agency funding disease-fighting technology, announced investments to support American COVID{{nbhyph}}19 vaccine development and the manufacturing of the most promising candidates.{{cite news | date=1 May 2020 |title=In quest for vaccine, US makes 'big bet' on company with unproven technology |work=CNN|url=https://www.cnn.com/2020/05/01/us/coronavirus-moderna-vaccine-invs/index.html |url-status=live |access-date=2 May 2020 |archive-url=https://web.archive.org/web/20200513005730/https://www.cnn.com/2020/05/01/us/coronavirus-moderna-vaccine-invs/index.html |archive-date=13 May 2020 |vauthors=Kuznia R, Polglase K, Mezzofiore G}} In May 2020, the government announced funding for a fast-track program called Operation Warp Speed.{{cite journal | vauthors=Cohen J |date=May 2020 |title=U.S. 'Warp Speed' vaccine effort comes out of the shadows |journal=Science |volume=368 |issue=6492 |pages=692–93 |bibcode=2020Sci...368..692C |doi=10.1126/science.368.6492.692 |pmid=32409451 | title-link = doi | doi-access = free }}{{cite news | vauthors = Sink J, Fabian J, Griffin R |date=15 May 2020 |title=Trump introduces 'Warp Speed' leaders to hasten COVID-19 vaccine |publisher=Bloomberg |url=https://www.bloomberg.com/news/articles/2020-05-15/trump-to-introduce-warp-speed-leaders-after-vaccine-criticism |url-status=live |access-date=15 May 2020 |archive-url=https://web.archive.org/web/20200521231515/https://www.bloomberg.com/news/articles/2020-05-15/trump-to-introduce-warp-speed-leaders-after-vaccine-criticism |archive-date=21 May 2020}} By March 2021, BARDA had funded an estimated $19.3 billion in COVID{{nbhyph}}19 vaccine development.{{cite news |vauthors=LaHucik K |date=17 June 2021 |title=U.S. injects $3B-plus into COVID-19 research to develop antiviral pill within a year |url=https://www.fiercebiotech.com/biotech/u-s-pledges-3b-plus-for-covid-19-antiviral-pill-within-a-year |access-date=11 July 2021 |website=Fierce Biotech |archive-date=9 October 2021 |archive-url=https://web.archive.org/web/20211009203610/https://www.fiercebiotech.com/biotech/u-s-pledges-3b-plus-for-covid-19-antiviral-pill-within-a-year |url-status=live }}

Large pharmaceutical companies with experience in making vaccines at scale, including Johnson & Johnson, AstraZeneca, and GlaxoSmithKline (GSK), formed alliances with biotechnology companies, governments, and universities to accelerate progress toward effective vaccines.

{{main|COVID-19 vaccine clinical research}}

{{excerpt|hat=no|only=paragraphs|COVID-19 vaccine clinical research}}

{{main|Embolic and thrombotic events after COVID-19 vaccination}}

{{excerpt|hat=no|only=paragraphs|Embolic and thrombotic events after COVID-19 vaccination}}

{{Excerpt|hat=no|History of COVID-19 vaccine development}}In November 2021, the full nucleotide sequences of the AstraZeneca and Pfizer/BioNTech vaccines were released by the UK Medicines and Healthcare products Regulatory Agency in response to a freedom of information request.{{cite Q|Q109371097}}{{cite web |date=2 November 2021 |title=Sequences of Covid-19 vaccines released via WhatDoTheyKnow |url=https://www.mysociety.org/2021/11/02/sequences-of-covid-19-vaccines-released-via-whatdotheyknow/ |url-status=live |archive-url=https://web.archive.org/web/20211105153752/https://www.mysociety.org/2021/11/02/sequences-of-covid-19-vaccines-released-via-whatdotheyknow/ |archive-date=5 November 2021 |access-date=2 November 2021 |publisher=mySociety |vauthors=Taylor R}}

File:2021- COVID-19 death rates by vaccination status - US.svg

File:COVID-19 vaccines lives saved.png

{{Excerpt|COVID-19 vaccine efficacy|Effectiveness}}An analysis involving more than 20 million adults found that vaccinated people had a lower risk of long COVID compared to those who had not had a COVID-19 vaccine.{{cite journal | vauthors = Català M, Mercadé-Besora N, Kolde R, Trinh NT, Roel E, Burn E, Rathod-Mistry T, Kostka K, Man WY, Delmestri A, Nordeng HM, Uusküla A, Duarte-Salles T, Prieto-Alhambra D, Jödicke AM | title = The effectiveness of COVID-19 vaccines to prevent long COVID symptoms: staggered cohort study of data from the UK, Spain, and Estonia | journal = The Lancet. Respiratory Medicine | volume = 12 | issue = 3 | pages = 225–236 | date = March 2024 | pmid = 38219763 | doi = 10.1016/s2213-2600(23)00414-9 | doi-access = free }}{{Cite journal |title=Vaccines reduce the risk of long COVID |url=https://evidence.nihr.ac.uk/alert/vaccines-reduce-the-risk-of-long-covid/ |journal=NIHR Evidence|date=2024 |doi=10.3310/nihrevidence_63203 |doi-access=free }}

As of 2021, available evidence shows that fully vaccinated individuals and those previously infected with SARS-CoV-2 have a low risk of subsequent infection for at least six months.{{cite web|date=29 October 2021|title=Science Brief: SARS-CoV-2 Infection-induced and Vaccine-induced Immunity|url=https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/vaccine-induced-immunity.html|access-date=4 December 2021|website=Centers for Disease Control and Prevention (CDC)|archive-date=4 December 2021|archive-url=https://web.archive.org/web/20211204081226/https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/vaccine-induced-immunity.html|url-status=live}} {{PD-notice}}{{cite journal |vauthors=Levin EG, Lustig Y, Cohen C, Fluss R, Indenbaum V, Amit S, Doolman R, Asraf K, Mendelson E, Ziv A, Rubin C, Freedman L, Kreiss Y, Regev-Yochay G |date=December 2021 |title=Waning Immune Humoral Response to BNT162b2 Covid-19 Vaccine over 6 Months |journal=The New England Journal of Medicine |volume=385 |issue=24 |pages=e84 |doi=10.1056/NEJMoa2114583 |pmc=8522797 |pmid=34614326 | title-link = doi | doi-access = free }}{{cite web |date=29 November 2021 |title=COVID-19 Booster Shot |url=https://www.cdc.gov/coronavirus/2019-ncov/vaccines/booster-shot.html |url-status=live |archive-url=https://web.archive.org/web/20210821000645/https://www.cdc.gov/coronavirus/2019-ncov/vaccines/booster-shot.html |archive-date=21 August 2021 |access-date=4 December 2021 |website=Centers for Disease Control and Prevention}} There is insufficient data to determine an antibody titer threshold that indicates when an individual is protected from infection. Multiple studies show that antibody titers are associated with protection at the population level, but individual protection titers remain unknown. For some populations, such as the elderly and the immunocompromised, protection levels may be reduced after both vaccination and infection. Available evidence indicates that the level of protection may not be the same for all variants of the virus.

As of December 2021, there are no FDA-authorized or approved tests that providers or the public can use to determine if a person is protected from infection reliably.

As of March 2022, elderly residents' protection against severe illness, hospitalization, and death in English care homes was high immediately after vaccination, but protection declined significantly in the months following vaccination. Protection among care home staff, who were younger, declined much more slowly. Regular boosters are recommended for older people, and boosters for care home residents every six months appear reasonable.{{cite news | vauthors=Devlin H | title=Covid immunity declines steeply in care home residents in England – study | website=The Guardian | date=18 March 2022 | url=https://www.theguardian.com/world/2022/mar/18/covid-immunity-declines-steeply-in-care-home-residents-study | access-date=12 May 2022 | archive-date=23 March 2022 | archive-url=https://web.archive.org/web/20220323091154/https://www.theguardian.com/world/2022/mar/18/covid-immunity-declines-steeply-in-care-home-residents-study | url-status=live }}

The US Centers for Disease Control and Prevention (CDC) recommends a fourth dose of the Pfizer mRNA vaccine {{as of|2022|March|lc=y}} for "certain immunocompromised individuals and people over the age of 50".{{cite news | vauthors = Kimball S |title=CDC recommends fourth Pfizer and Moderna Covid vaccine doses for people age 50 and older |url= https://www.cnbc.com/2022/03/29/fda-authorizes-fourth-pfizer-covid-vaccine-dose-for-people-age-50-and-older-.html |access-date=22 August 2022 |work=CNBC |archive-date=3 September 2022 |archive-url= https://web.archive.org/web/20220903154426/https://www.cnbc.com/2022/03/29/fda-authorizes-fourth-pfizer-covid-vaccine-dose-for-people-age-50-and-older-.html |url-status=live }}{{cite press release |title=Coronavirus Disease 2019 |url=https://www.cdc.gov/media/releases/2022/s0328-covid-19-boosters.html |website=Centers for Disease Control and Prevention |access-date=22 August 2022 |date=29 March 2022 |archive-date=1 September 2022 |archive-url= https://web.archive.org/web/20220901053403/https://www.cdc.gov/media/releases/2022/s0328-covid-19-boosters.html |url-status=live }}

In contrast to other investigated prior variants, the SARS-CoV-2 Omicron variant{{cite journal | vauthors = Wang R, Chen J, Wei GW | title = Mechanisms of SARS-CoV-2 Evolution Revealing Vaccine-Resistant Mutations in Europe and America | journal = The Journal of Physical Chemistry Letters | volume = 12 | issue = 49 | pages = 11850–11857 | date = December 2021 | pmid = 34873910 | pmc = 8672435 | doi = 10.1021/acs.jpclett.1c03380 | url = https://users.math.msu.edu/users/weig/paper/p272.pdf | url-status = live | access-date = 27 January 2022 | archive-url = https://web.archive.org/web/20211218184752/https://users.math.msu.edu/users/weig/paper/p272.pdf | archive-date = 18 December 2021 }}{{cite news |date=5 January 2022 |title=Study findings suggest spread of Omicron can be ascribed to immune evasiveness rather than an increase in transmissibility |work=News-Medical.net |url=https://www.news-medical.net/news/20220105/Study-findings-suggest-spread-of-Omicron-can-be-ascribed-to-immune-evasiveness-rather-than-an-increase-in-transmissibility.aspx |url-status=live |access-date=17 January 2022 |archive-url=https://web.archive.org/web/20220121182541/https://www.news-medical.net/news/20220105/Study-findings-suggest-spread-of-Omicron-can-be-ascribed-to-immune-evasiveness-rather-than-an-increase-in-transmissibility.aspx |archive-date=21 January 2022}}{{cite journal | vauthors = Cao Y, Wang J, Jian F, Xiao T, Song W, Yisimayi A, Huang W, Li Q, Wang P, An R, Wang J, Wang Y, Niu X, Yang S, Liang H, Sun H, Li T, Yu Y, Cui Q, Liu S, Yang X, Du S, Zhang Z, Hao X, Shao F, Jin R, Wang X, Xiao J, Wang Y, Xie XS | title = Omicron escapes the majority of existing SARS-CoV-2 neutralizing antibodies | journal = Nature | volume = 602 | issue = 7898 | pages = 657–663 | date = February 2022 | pmid = 35016194 | doi = 10.1038/d41586-021-03796-6 | pmc = 8866119 | s2cid = 245455422 }}{{cite journal | vauthors = Liu L, Iketani S, Guo Y, Chan JF, Wang M, Liu L, Luo Y, Chu H, Huang Y, Nair MS, Yu J, Chik KK, Yuen TT, Yoon C, To KK, Chen H, Yin MT, Sobieszczyk ME, Huang Y, Wang HH, Sheng Z, Yuen KY, Ho DD | title = Striking antibody evasion manifested by the Omicron variant of SARS-CoV-2 | journal = Nature | volume = 602 | issue = 7898 | pages = 676–681 | date = February 2022 | pmid = 35016198 | doi = 10.1038/d41586-021-03826-3 | s2cid = 245462866 | title-link = doi | doi-access = free }}{{cite journal | vauthors = Mohsin M, Mahmud S | title = Omicron SARS-CoV-2 variant of concern: A review on its transmissibility, immune evasion, reinfection, and severity | journal = Medicine | volume = 101 | issue = 19 | pages = e29165 | date = May 2022 | pmid = 35583528 | doi = 10.1097/MD.0000000000029165 | pmc = 9276130 | s2cid = 248858919 }} and its BA.4/5 subvariants{{cite news |date=2 May 2022 |title=How soon after catching COVID-19 can you get it again? |work=ABC News |url=https://www.abc.net.au/news/health/2022-05-03/covid-19-reinfection-what-are-the-odds-of-catching-it-twice/101024180 |access-date=24 June 2022 |archive-date=9 July 2022 |archive-url=https://web.archive.org/web/20220709233023/https://www.abc.net.au/news/health/2022-05-03/covid-19-reinfection-what-are-the-odds-of-catching-it-twice/101024180 |url-status=live }} have evaded immunity induced by vaccines, which may lead to breakthrough infections despite recent vaccination. Nevertheless, vaccines are thought to provide protection against severe illness, hospitalizations, and deaths due to Omicron.{{cite web |date=20 December 2021 |title=Omicron Variant: What You Need to Know |url=https://www.cdc.gov/coronavirus/2019-ncov/variants/omicron-variant.html |url-status=live |archive-url=https://web.archive.org/web/20220127152019/https://www.cdc.gov/coronavirus/2019-ncov/variants/omicron-variant.html |archive-date=27 January 2022 |access-date=27 January 2022 |website=Centers for Disease Control and Prevention }}

{{See also|Universal coronavirus vaccine}}

{{Excerpt|SARS-CoV-2 Omicron variant#Vaccine adjustments}}

As of 2022, fully vaccinated individuals with breakthrough infections with the SARS-CoV-2 delta (B.1.617.2) variant were found to have a peak viral load similar to unvaccinated cases and could transmit infection in household settings.{{cite journal | vauthors = Singanayagam A, Hakki S, Dunning J, Madon KJ, Crone MA, Koycheva A, Derqui-Fernandez N, Barnett JL, Whitfield MG, Varro R, Charlett A, Kundu R, Fenn J, Cutajar J, Quinn V, Conibear E, Barclay W, Freemont PS, Taylor GP, Ahmad S, Zambon M, Ferguson NM, Lalvani A | title = Community transmission and viral load kinetics of the SARS-CoV-2 delta (B.1.617.2) variant in vaccinated and unvaccinated individuals in the UK: a prospective, longitudinal, cohort study | journal = The Lancet. Infectious Diseases | volume = 22 | issue = 2 | pages = 183–195 | date = February 2022 | pmid = 34756186 | pmc = 8554486 | doi = 10.1016/S1473-3099(21)00648-4 }}

According to studies, the combination of two different COVID{{nbhyph}}19 vaccines, also called heterologous vaccination, cross-vaccination, or the mix-and-match method, provides protection equivalent to that of mRNA vaccines, including protection against the Delta variant. Individuals who receive the combination of two different vaccines produce strong immune responses, with side effects no worse than those caused by standard regimens.{{cite journal | vauthors = Callaway E | title = Mix-and-match COVID vaccines ace the effectiveness test | journal = Nature | date = October 2021 | pmid = 34675430 | doi = 10.1038/d41586-021-02853-4 | s2cid = 239455075 }}{{cite journal | vauthors = Rashedi R, Samieefar N, Masoumi N, Mohseni S, Rezaei N | title = COVID-19 vaccines mix-and-match: The concept, the efficacy and the doubts | journal = Journal of Medical Virology | volume = 94 | issue = 4 | pages = 1294–1299 | date = April 2022 | pmid = 34796525 | pmc = 8661746 | doi = 10.1002/jmv.27463 }}

Methotrexate reduces the immune response to COVID-19 vaccines, making them less effective.{{cite journal | vauthors = Al-Haideri MT, Mannani R, Kaboli R, Gharebakhshi F, Darvishzadehdeldari S, Tahmasebi S, Faramarzi F, Cotrina-Aliaga JC, Khorasani S, Alimohammadi M, Darvishi M, Akhavan-Sigari R | title = The effects of methotrexate on the immune responses to the COVID-19 vaccines in the patients with immune-mediated inflammatory disease: A systematic review of clinical evidence | journal = Transplant Immunology | volume = 79 | pages = 101858 | date = August 2023 | pmid = 37236514 | pmc = 10205646 | doi = 10.1016/j.trim.2023.101858 }}{{Cite journal |date=26 January 2023 |title=A pause in methotrexate treatment boosted the immune response to the COVID-19 vaccine |url=https://evidence.nihr.ac.uk/alert/a-short-pause-methotrexate-treatment-boosted-immune-response-covid-19-vaccine/ |journal=NIHR Evidence |publisher=National Institute for Health and Care Research |doi=10.3310/nihrevidence_56391}} Pausing methotrexate for two weeks following COVID-19 vaccination may result in improved immunity. Not taking the medicine for two weeks might result in a minor increase of inflammatory disease flares in some people.{{cite journal | vauthors = Wroński J, Ciechomska M, Kuca-Warnawin E | title = Impact of methotrexate treatment on vaccines immunogenicity in adult rheumatological patients - Lessons learned from the COVID-19 pandemic | journal = Biomedicine & Pharmacotherapy | volume = 165 | pages = 115254 | date = September 2023 | pmid = 37542854 | doi = 10.1016/j.biopha.2023.115254 | doi-access = free }}{{cite journal | vauthors = Imran M, Ali S, Ibrahim AA, Amjad A, Tanveer A, Khalil S, Ali M, Abuelazm M | title = Effect of methotrexate hold on COVID-19 vaccine response in the patients with autoimmune inflammatory disorders: a systematic review and meta-analysis | journal = Clinical Rheumatology | volume = 43 | issue = 7 | pages = 2203–2214 | date = July 2024 | pmid = 38802670 | doi = 10.1007/s10067-024-07013-3 }}{{cite journal | vauthors = Abhishek A, Peckham N, Pade C, Gibbons JM, Cureton L, Francis A, Barber V, Williams JA, Appelbe D, Eldridge L, Julier P, Altmann DM, Bluett J, Brooks T, Coates LC, Rombach I, Semper A, Otter A, Valdes AM, Nguyen-Van-Tam JS, Williams HC, Boyton RJ, McKnight Á, Cook JA | title = Effect of a 2-week interruption in methotrexate treatment on COVID-19 vaccine response in people with immune-mediated inflammatory diseases (VROOM study): a randomised, open label, superiority trial | journal = The Lancet. Rheumatology | volume = 6 | issue = 2 | pages = e92–e104 | date = February 2024 | pmid = 38267107 | doi = 10.1016/S2665-9913(23)00298-9 }}

For most people, the side effects, also called adverse effects, from COVID{{nbhyph}}19 vaccines are mild and can be managed at home. The adverse effects of the COVID{{nbhyph}}19 vaccination are similar to those of other vaccines, and severe adverse effects are rare.{{cite journal | vauthors = Kouhpayeh H, Ansari H | title = Adverse events following COVID-19 vaccination: A systematic review and meta-analysis | journal = International Immunopharmacology | volume = 109 | pages = 108906 | date = August 2022 | pmid = 35671640 | doi = 10.1016/j.intimp.2022.108906 | pmc = 9148928 }}{{cite journal | vauthors = Graña C, Ghosn L, Evrenoglou T, Jarde A, Minozzi S, Bergman H, Buckley BS, Probyn K, Villanueva G, Henschke N, Bonnet H, Assi R, Menon S, Marti M, Devane D, Mallon P, Lelievre JD, Askie LM, Kredo T, Ferrand G, Davidson M, Riveros C, Tovey D, Meerpohl JJ, Grasselli G, Rada G, Hróbjartsson A, Ravaud P, Chaimani A, Boutron I | title = Efficacy and safety of COVID-19 vaccines | journal = The Cochrane Database of Systematic Reviews | volume = 12 | issue = 12 | pages = CD015477 | date = December 2022 | pmid = 36473651 | doi = 10.1002/14651858.CD015477 | pmc = 9726273 }} Adverse effects from the vaccine are higher than placebo, but placebo arms of vaccine trials still reported adverse effects that can be attributed to the nocebo effect.{{cite journal | vauthors = Haas JW, Bender FL, Ballou S, Kelley JM, Wilhelm M, Miller FG, Rief W, Kaptchuk TJ | title = Frequency of Adverse Events in the Placebo Arms of COVID-19 Vaccine Trials: A Systematic Review and Meta-analysis | journal = JAMA Network Open | volume = 5 | issue = 1 | pages = e2143955 | date = January 2022 | pmid = 35040967 | doi = 10.1001/jamanetworkopen.2021.43955 | pmc = 8767431 }}

All vaccines that are administered via intramuscular injection, including COVID{{nbhyph}}19 vaccines, have side effects related to the mild trauma associated with the procedure and the introduction of a foreign substance into the body.{{cite book | vauthors = Polania Gutierrez JJ, Munakomi S | date = January 2020 | chapter = Intramuscular Injection | chapter-url = https://www.ncbi.nlm.nih.gov/books/NBK556121/ | location = Treasure Island (FL) | publisher = StatPearls Publishing | title = StatPearls | pmid = 32310581 | access-date = 24 July 2021 | archive-date = 8 December 2020 | archive-url = https://web.archive.org/web/20201208182850/https://www.ncbi.nlm.nih.gov/books/NBK556121/ | url-status = live }} These include soreness, redness, rash, and inflammation at the injection site. Other common side effects include fatigue, headache, myalgia (muscle pain), and arthralgia (joint pain), all of which generally resolve without medical treatment within a few days.{{cite report |url=https://apps.who.int/iris/rest/bitstreams/1330343/retrieve |title=Background document on the mRNA-1273 vaccine (Moderna) against COVID-19 |date=February 2021 |publisher=World Health Organization (WHO) |id=WHO/2019-nCoV/vaccines/SAGE_recommendation/mRNA-1273/background/2021.1 |hdl-access=free |hdl=10665/339218 |access-date=24 July 2021 |archive-date=13 June 2021 |archive-url=https://web.archive.org/web/20210613133906/https://apps.who.int/iris/rest/bitstreams/1330343/retrieve |url-status=live }}{{cite web |title=Background document on the mRNA-1273 vaccine (Moderna) against COVID-19 |url=https://www.who.int/publications/i/item/background-document-on-the-mrna-1273-vaccine-(moderna)-against-covid-19 |access-date=23 January 2022 |publisher=World Health Organization (WHO) |archive-date=26 January 2022 |archive-url=https://web.archive.org/web/20220126053538/https://www.who.int/publications/i/item/background-document-on-the-mrna-1273-vaccine-(moderna)-against-covid-19 |url-status=live }} Like any other vaccine, some people are allergic to one or more ingredients in COVID{{nbhyph}}19 vaccines. Typical side effects are stronger and more common in younger people and in subsequent doses, and up to 20% of people report a disruptive level of side effects after the second dose of an mRNA vaccine.{{cite journal | vauthors = Huang Z, Su Y, Zhang T, Xia N | title = A review of the safety and efficacy of current COVID-19 vaccines | journal = Frontiers of Medicine | volume = 16 | issue = 1 | pages = 39–55 | date = February 2022 | pmid = 35122210 | pmc = 8815389 | doi = 10.1007/s11684-021-0893-y }} These side effects are less common or weaker in inactivated vaccines. COVID{{nbhyph}}19 vaccination-related enlargement of lymph nodes happens in 11.6% of those who received one dose of the vaccine and in 16% of those who received two doses.{{cite journal | vauthors = Tu W, Gierada DS, Joe BN | title = COVID-19 Vaccination-Related Lymphadenopathy: What To Be Aware Of | journal = Radiology: Imaging Cancer | volume = 3 | issue = 3 | pages = e210038 | date = May 2021 | pmid = 33874733 | pmc = 8049171 | doi = 10.1148/rycan.2021210038 }}

Experiments in mice show that intramuscular injections of lipid excipient nanoparticles (an inactive substance that serves as the vehicle or medium) cause particles to enter the blood plasma and many organs, with higher concentrations found in the liver and lower concentrations in the spleen, adrenal glands, and ovaries. The highest concentration of nanoparticles was found at the injection site itself.{{cite web |title=Nonclinical Evaluation Report: BNT162b2 [mRNA] COVID-19 vaccine |url=https://www.tga.gov.au/sites/default/files/foi-2389-06.pdf |website=Australian Department of Health: Therapeutic Goods Administration |access-date=25 March 2023 |archive-date=28 March 2023 |archive-url=https://web.archive.org/web/20230328233750/https://www.tga.gov.au/sites/default/files/foi-2389-06.pdf |url-status=live }}

COVID{{nbhyph}}19 vaccination is safe for breastfeeding people.{{cite web |publisher=NHS |url=https://www.nhs.uk/conditions/coronavirus-covid-19/coronavirus-vaccination/pregnancy-breastfeeding-fertility-and-coronavirus-covid-19-vaccination/ |date=5 October 2022 |title=Pregnancy, breastfeeding, fertility and coronavirus (COVID-19) vaccination |access-date=15 October 2022 |archive-date=15 October 2022 |archive-url=https://web.archive.org/web/20221015155517/https://www.nhs.uk/conditions/coronavirus-covid-19/coronavirus-vaccination/pregnancy-breastfeeding-fertility-and-coronavirus-covid-19-vaccination/ |url-status=live }} Temporary changes to the menstrual cycle in young women have been reported. However, these changes are "small compared with natural variation and quickly reverse."{{cite journal | vauthors = Male V | title = Menstruation and covid-19 vaccination | journal = BMJ | volume = 376 | pages = o142 | date = January 2022 | pmid = 35082132 | doi = 10.1136/bmj.o142 | s2cid = 246287912 | title-link = doi | doi-access = free | hdl = 10044/1/94577 | hdl-access = free }} In one study, women who received both doses of a two-dose vaccine during the same menstrual cycle (an atypical situation) may see their next period begin a couple of days late. They have about twice the usual risk of a clinically significant delay (about 10% of these women, compared to about 4% of unvaccinated women). Cycle lengths return to normal after two menstrual cycles post-vaccination. Women who received doses in separate cycles had approximately the same natural variation in cycle lengths as unvaccinated women. Other temporary menstrual effects have been reported, such as heavier than normal menstrual bleeding after vaccination.

Serious adverse events associated COVID{{nbhyph}}19 vaccines are generally rare but of high interest to the public.{{cite journal |vauthors=Montgomery J, Ryan M, Engler R, Hoffman D, McClenathan B, Collins L, Loran D, Hrncir D, Herring K, Platzer M, Adams N, Sanou A, Cooper LT |date=October 2021 |title=Myocarditis Following Immunization With mRNA COVID-19 Vaccines in Members of the US Military |journal=JAMA Cardiology |volume=6 |issue=10 |pages=1202–06 |doi=10.1001/jamacardio.2021.2833 |pmc=8243257 |pmid=34185045 | title-link = doi | doi-access = free }} The official databases of reported adverse events include

• the World Health Organization's VigiBase;
• the United States Vaccine Adverse Events Reporting System (VAERS);
• the United Kingdom's Yellow Card Scheme;
• the European Medicines Agency's EudraVigilance system, which operates a regular transfer of data on suspected adverse drug reactions occurring in the EU to WHO's Uppsala Monitoring Centre.{{cite web | url=https://www.ema.europa.eu/en/partners-networks/international-activities/multilateral-coalitions-initiatives/world-health-organization-who#:~:text=EU%20Member%20States%2C%20EMA%20and,EC%20)%20No%20726%2F2004 | title=World Health Organization (WHO) | date=17 September 2018 | access-date=19 September 2023 | archive-date=4 October 2023 | archive-url=https://web.archive.org/web/20231004202200/https://www.ema.europa.eu/en/partners-networks/international-activities/multilateral-coalitions-initiatives/world-health-organization-who#:~:text=EU%20Member%20States%2C%20EMA%20and,EC%20)%20No%20726%2F2004 | url-status=live }}

Increased public awareness of these reporting systems and the extra reporting requirements under US FDA Emergency Use Authorization rules have increased reported adverse events.{{cite web |vauthors=McDonald J |date=23 December 2021 |title=Increase in COVID-19 VAERS Reports Due To Reporting Requirements, Intense Scrutiny of Widely Given Vaccines |url=https://www.factcheck.org/2021/12/scicheck-increase-in-covid-19-vaers-reports-due-to-reporting-requirements-intense-scrutiny-of-widely-given-vaccines/ |access-date=20 May 2022 |website=FactCheck.org |archive-date=20 May 2022 |archive-url=https://web.archive.org/web/20220520020203/https://www.factcheck.org/2021/12/scicheck-increase-in-covid-19-vaers-reports-due-to-reporting-requirements-intense-scrutiny-of-widely-given-vaccines/ |url-status=live }} Serious side effects are an ongoing area of study, and resources have been allocated to try to better understand them.{{cite web | title = Treating Post-Vac-Syndrome | work = Deutsche Welle | date = 11 October 2022 | url = https://www.dw.com/en/treating-the-long-term-symptoms-of-post-vac-syndrome/video-63710911 | archive-url = https://web.archive.org/web/20230417113134/https://www.dw.com/en/treating-the-long-term-symptoms-of-post-vac-syndrome/video-63710911| archive-date = 17 April 2023}}{{cite web | work = Universitätsklinikum Giessen und Marburg (UKGM) | title = Spezialsprechstunde Post-Vax | trans-title = Post-Vac Special Consultation | language = de | url = https://www.ukgm.de/ugm_2/deu/umr_kar/51186.html | archive-url = https://web.archive.org/web/20230504041112/https://www.ukgm.de/ugm_2/deu/umr_kar/51186.html| archive-date=4 May 2023}}{{cite web | work = Frankfurter Allgemeine Zeitung GmbH | url = https://m.faz.net/aktuell/rhein-main/corona-impfschaeden-uniklinik-marburg-oeffnet-eigene-ambulanz-18796703.html | archive-url = https://web.archive.org/web/20240308030343/https://www.faz.net/aktuell/rhein-main/corona-impfschaeden-uniklinik-marburg-oeffnet-eigene-ambulanz-18796703.html | archive-date=8 March 2024 | language = de | title = Corona-Impfschäden: Uniklinik Marburg öffnet eigene Ambulanz | trans-title = Corona vaccine damage: Marburg University Hospital opens its own outpatient clinic| date = 3 April 2023 }} Research currently indicates that the rate and type of side effects are lower-risk than infection. For example, although vaccination may trigger some side effects, the effects experienced from an infection could be worse. Neurological side effects from getting COVID{{nbhyph}}19 are hundreds of times more likely than from vaccination.{{cite journal | vauthors = Frontera JA, Tamborska AA, Doheim MF, Garcia-Azorin D, Gezegen H, Guekht A, Yusof Khan AH, Santacatterina M, Sejvar J, Thakur KT, Westenberg E, Winkler AS, Beghi E | title = Neurological Events Reported after COVID-19 Vaccines: An Analysis of VAERS | journal = Annals of Neurology | volume = 91 | issue = 6 | pages = 756–771 | date = March 2022 | pmid = 35233819 | doi = 10.1002/ana.26339 | pmc = 9082459 | title-link = doi | doi-access = free }}

Documented rare serious effects include:

• anaphylaxis, a severe type of allergic reaction.{{cite journal | vauthors = Altmann DM, Boyton RJ | title = COVID-19 vaccination: The road ahead | journal = Science | volume = 375 | issue = 6585 | pages = 1127–1132 | date = March 2022 | pmid = 35271316 | doi = 10.1126/science.abn1755 | bibcode = 2022Sci...375.1127A | s2cid = 247384207 }} Anaphylaxis affects one person per 250,000 to 400,000 doses administered.{{cite report | title=COVID-19 vaccines safety update | url=https://www.ema.europa.eu/documents/covid-19-vaccine-safety-update/covid-19-vaccines-safety-update-14-july-2022_en.pdf | date= | access-date=6 September 2022 | archive-date=3 August 2022 | archive-url=https://web.archive.org/web/20220803225933/https://www.ema.europa.eu/en/documents/covid-19-vaccine-safety-update/covid-19-vaccines-safety-update-14-july-2022_en.pdf | url-status=live }} According to a 2022 systematic review, the mortality rate of people with anaphylaxis following COVID‐19 vaccination was 0.5%.{{cite journal | vauthors = Paul P, Janjua E, AlSubaie M, Ramadorai V, Mushannen B, Vattoth AL, Khan W, Bshesh K, Nauman A, Mohammed I, Bouhali I, Khalid M, Zakaria D | title = Anaphylaxis and Related Events Following COVID-19 Vaccination: A Systematic Review | journal = Journal of Clinical Pharmacology | volume = 62 | issue = 11 | pages = 1335–1349 | date = November 2022 | pmid = 35794852 | doi = 10.1002/jcph.2120 | pmc = 9349886 }}

• blood clots (thrombosis). These vaccine-induced immune thrombocytopenia and thrombosis are associated with vaccines using an adenovirus system (Janssen and Oxford-AstraZeneca). These affect about one person per 100,000.
• myocarditis and pericarditis, or inflammation of the heart. There is a rare risk of myocarditis (inflammation of the heart muscle) or pericarditis (inflammation of the membrane covering the heart) after the mRNA COVID{{nbhyph}}19 vaccines (Moderna or Pfizer-BioNTech). The risk of myocarditis after COVID{{nbhyph}}19 vaccination is estimated to be 0.3 to 5 cases per 100,000 persons, with the highest risk in young males.{{cite journal | vauthors = Basso C | title = Myocarditis | journal = The New England Journal of Medicine | volume = 387 | issue = 16 | pages = 1488–1500 | date = October 2022 | pmid = 36260793 | doi = 10.1056/NEJMra2114478 | s2cid = 240234869 | hdl = 11577/3479721 | hdl-access = free }} In an Israeli nation-wide population-based study (in which the Pfizer-BioNTech vaccine was exclusively given), the incidence rate of myocarditis was 54 cases out of 2.5 million vaccine recipients, with an overall incidence rate of 2 cases per 100,000 persons, with the highest incidence seen in young males (aged 16 to 29) at 10 cases per 100,000 vaccine recipients. Of the cases of myocarditis seen, 76% were mild in severity, with one case of cardiogenic shock (heart failure) and one death (in a person with a preexisting heart condition) reported within the 83-day follow-up period.{{cite journal | vauthors = Witberg G, Barda N, Hoss S, Richter I, Wiessman M, Aviv Y, Grinberg T, Auster O, Dagan N, Balicer RD, Kornowski R | title = Myocarditis after Covid-19 Vaccination in a Large Health Care Organization | journal = The New England Journal of Medicine | volume = 385 | issue = 23 | pages = 2132–2139 | date = December 2021 | pmid = 34614329 | pmc = 8531986 | doi = 10.1056/NEJMoa2110737 | s2cid = 238421512 }} COVID{{nbhyph}}19 vaccines may protect against myocarditis due to subsequent COVID{{nbhyph}}19 infection.{{cite journal | vauthors = Patone M, Mei XW, Handunnetthi L, Dixon S, Zaccardi F, Shankar-Hari M, Watkinson P, Khunti K, Harnden A, Coupland CA, Channon KM, Mills NL, Sheikh A, Hippisley-Cox J | title = Risk of Myocarditis After Sequential Doses of COVID-19 Vaccine and SARS-CoV-2 Infection by Age and Sex | journal = Circulation | volume = 146 | issue = 10 | pages = 743–754 | date = September 2022 | pmid = 35993236 | pmc = 9439633 | doi = 10.1161/CIRCULATIONAHA.122.059970 }} The risk of myocarditis and pericarditis is significantly higher (up to 11 times higher with respect to myocarditis) after COVID{{nbhyph}}19 infection as compared to COVID{{nbhyph}}19 vaccination, with the possible exception of younger men (less than 40 years old) who may have a higher risk of myocarditis after the second Moderna mRNA vaccine (an additional 97 cases of myocarditis per 1 million persons vaccinated). The mortality rate from myocarditis post-vaccination is extremely low. According to a 2022 study, of patients diagnosed with myocarditis (in both vaccination and COVID-19 cohort) 1.07% were hospitalized and 0.015% died.{{cite journal | vauthors = Voleti N, Reddy SP, Ssentongo P | title = Myocarditis in SARS-CoV-2 infection vs. COVID-19 vaccination: A systematic review and meta-analysis | journal = Frontiers in Cardiovascular Medicine | volume = 9 | pages = 951314 | year = 2022 | pmid = 36105535 | pmc = 9467278 | doi = 10.3389/fcvm.2022.951314 | doi-access = free }}

• thrombotic thrombocytopenia and other autoimmune diseases, which have been reported as adverse events after the COVID{{nbhyph}}19 vaccine.{{cite journal | vauthors = Chen Y, Xu Z, Wang P, Li XM, Shuai ZW, Ye DQ, Pan HF | title = New-onset autoimmune phenomena post-COVID-19 vaccination | journal = Immunology | volume = 165 | issue = 4 | pages = 386–401 | date = April 2022 | pmid = 34957554 | doi = 10.1111/imm.13443 | s2cid = 245522029 | title-link = doi | doi-access = free }}

There are rare reports of subjective hearing changes, including tinnitus, after vaccination.{{cite journal | vauthors = Jafari Z, Kolb BE, Mohajerani MH | title = Hearing Loss, Tinnitus, and Dizziness in COVID-19: A Systematic Review and Meta-Analysis | journal = The Canadian Journal of Neurological Sciences | volume = 49 | issue = 2 | pages = 184–195 | date = March 2022 | pmid = 33843530 | pmc = 8267343 | doi = 10.1017/cjn.2021.63 | title-link = doi | doi-access = free }}{{cite journal |vauthors=Slomski A |date=May 2022 |title=Studies Examine Risk of Hearing Loss After COVID-19 Vaccination |journal=JAMA |volume=327 |issue=17 |pages=1641 |doi=10.1001/jama.2022.6719 |pmid=35503358 |s2cid=248502943| title-link = doi | doi-access = free }}{{cite journal | vauthors = Dorney I, Bobak L, Otteson T, Kaelber DC | title = Prevalence of New-Onset Tinnitus after COVID-19 Vaccination with Comparison to Other Vaccinations | journal = The Laryngoscope | pages = 1722–1725 | date = September 2022 | volume = 133 | issue = 7 | pmid = 36098476 | doi = 10.1002/lary.30395 | pmc = 9539087 }}

{{main|Deployment of COVID-19 vaccines}}

Note about the table in this section: number and percentage of people who have received at least one dose of a COVID{{nbhyph}}19 vaccine (unless noted otherwise). May include vaccination of non-citizens, which can push totals beyond 100% of the local population. The table is updated daily by a bot.The table data is automatically updated daily by a bot; see Template:COVID-19 data for more information. Scroll down past the table to find the documentation and the main reference. See also: :Category:Automatically updated COVID-19 pandemic table templates.

{{Excerpt|hat=no|Deployment of COVID-19 vaccines|only=paragraphs}}

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|File:World map of share of people who received at least one dose of COVID-19 vaccine by country.png

|Share of people who have received at least one dose of a COVID-19 vaccine relative to a country's total population. The date is on the map. Commons source.

|File:World map of COVID-19 vaccination doses administered per 100 people by country or territory.png

|COVID-19 vaccine doses administered per 100 people by country. The date is on the map. Commons source.

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{{Further|Deployment of COVID-19 vaccines#Equitable access|TRIPS Agreement waiver|COVAX}}

Countries have extremely unequal access to the COVID{{nbhyph}}19 vaccine. Vaccine equity has not been achieved or even approximated. The inequity has harmed both countries with poor access and countries with good access.

Nations pledged to buy doses of the COVID{{nbhyph}}19 vaccines before the doses were available. Though high-income nations represent only 14% of the global population, as of 15 November 2020, they had contracted to buy 51% of all pre-sold doses. Some high-income nations bought more doses than would be necessary to vaccinate their entire populations.

File:Fábrica do DF produz vacina Sputnik V (50874839072).jpg

In January 2021, WHO Director-General Tedros Adhanom Ghebreyesus warned of problems with equitable distribution: "More than 39 million doses of vaccine have now been administered in at least 49 higher-income countries. Just 25 doses have been given in one lowest-income country. Not 25 million; not 25 thousand; just 25."{{cite web|vauthors=Adhanom Ghebreyesus T|date=18 January 2021|title=WHO Director-General's opening remarks at 148th session of the Executive Board|url=https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-at-148th-session-of-the-executive-board|access-date=25 January 2021|work=World Health Organization (WHO)|archive-date=12 November 2021|archive-url=https://web.archive.org/web/20211112045815/https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-at-148th-session-of-the-executive-board|url-status=live}}

File:Inside view of the vaccination centre 2.jpg, Belgium, February 2021]]

In March 2021, it was revealed that the US attempted to convince Brazil not to purchase the Sputnik V COVID{{nbhyph}}19 vaccine, fearing "Russian influence" in Latin America.{{cite web|date=15 March 2021|title=U.S. pressured Brazil to ditch Russia's Sputnik V vaccine|url=https://brazilian.report/coronavirus-brazil-live-blog/2021/03/15/us-pressured-brazil-ditch-russias-sputnik-v-vaccine/|access-date=21 March 2021|website=The Brazilian Report|archive-date=15 March 2021|archive-url=https://web.archive.org/web/20210315132124/https://brazilian.report/coronavirus-brazil-live-blog/2021/03/15/us-pressured-brazil-ditch-russias-sputnik-v-vaccine/|url-status=live}} Some nations involved in long-standing territorial disputes have reportedly had their access to vaccines blocked by competing nations; Palestine has accused Israel of blocking vaccine delivery to Gaza, while Taiwan has suggested that China has hampered its efforts to procure vaccine doses.{{cite news |date=16 February 2021 |title=Israel blocked Covid vaccines from entering Gaza, say Palestinians |work=The Guardian |url=https://www.theguardian.com/world/2021/feb/16/israel-blocked-covid-vaccines-from-entering-gaza-say-palestinians |access-date=17 February 2021 |vauthors=Holmes O |archive-date=16 February 2021 |archive-url=https://web.archive.org/web/20210216135520/https://www.theguardian.com/world/2021/feb/16/israel-blocked-covid-vaccines-from-entering-gaza-say-palestinians |url-status=live }}{{cite news |date=4 February 2021 |title=Israel's Vaccine Success Unleashes a Debate on Palestinian Inequities |work=The New York Times |url=https://www.nytimes.com/2021/02/04/world/middleeast/israel-palestinians-vaccine.html |archive-url=https://ghostarchive.org/archive/20211228/https://www.nytimes.com/2021/02/04/world/middleeast/israel-palestinians-vaccine.html |archive-date=28 December 2021 |url-access=limited |access-date=17 February 2021 |vauthors=Rasgon A| url-status=live }}{{cite news |vauthors=Horton C |date=17 February 2021 |title=Taiwan Concerned China May Have Blocked Vaccine Purchase |work=Bloomberg |url=https://www.bloomberg.com/news/articles/2021-02-17/taiwan-concerned-china-may-have-blocked-vaccine-purchase |access-date=17 February 2021 |archive-date=17 February 2021 |archive-url=https://web.archive.org/web/20210217092645/https://www.bloomberg.com/news/articles/2021-02-17/taiwan-concerned-china-may-have-blocked-vaccine-purchase |url-status=live }}

A single dose of the COVID{{nbhyph}}19 vaccines by AstraZeneca would cost 47 Egyptian pounds (EGP), and the authorities are selling them for between 100 and 200 EGP. A report by the Carnegie Endowment for International Peace cited the poverty rate in Egypt as around 29.7 percent, which constitutes approximately 30.5 million people, and claimed that about 15 million Egyptians would be unable to gain access to the luxury of vaccination. A human rights lawyer, Khaled Ali, launched a lawsuit against the government, forcing them to provide vaccinations free of charge to all members of the public.{{cite web|url=https://carnegieendowment.org/sada/2021/03/playing-politics-with-poverty-sisis-covid-19-vaccine-strategy?lang=en|title=Playing Politics with Poverty: Sisi's COVID-19 Vaccine Strategy|access-date=25 February 2021|website=Carnegie Endowment for International Peace|archive-date=28 February 2021|archive-url=https://web.archive.org/web/20210228160344/https://carnegieendowment.org/sada/83933|url-status=live}}

File:Covid vaccination for children aged 12-14 in India 03cropped.jpg, India]]

According to immunologist Anthony Fauci, mutant strains of the virus and limited vaccine distribution pose continuing risks, and he said, "we have to get the entire world vaccinated, not just our own country."{{cite web|vauthors=Strazewski L|date=9 February 2021|title=Dr. Fauci: Variants reveal COVID-19 vaccination as global job|url=https://www.ama-assn.org/delivering-care/public-health/dr-fauci-variants-reveal-covid-19-vaccination-global-job|access-date=4 March 2021|website=American Medical Association|archive-date=10 October 2021|archive-url=https://web.archive.org/web/20211010115053/https://www.ama-assn.org/delivering-care/public-health/dr-fauci-variants-reveal-covid-19-vaccination-global-job|url-status=live}} Edward Bergmark and Arick Wierson are calling for a global vaccination effort and wrote that the wealthier nations' "me-first" mentality could ultimately backfire because the spread of the virus in poorer countries would lead to more variants, against which the vaccines could be less effective.{{cite web|vauthors=Bergmark E, Wierson A|date=26 February 2021|title=Opinion: Without a global vaccine plan, coronavirus variants could lead to untold number of deaths|url=https://www.cnn.com/2021/02/26/perspectives/covid-variants-global-vaccination/index.html|access-date=4 March 2021|website=CNN |archive-date=19 October 2021|archive-url=https://web.archive.org/web/20211019124133/https://www.cnn.com/2021/02/26/perspectives/covid-variants-global-vaccination/index.html|url-status=live}}

In March 2021, the United States, Britain, European Union member states, and some other members of the World Trade Organization (WTO) blocked a push by more than eighty developing countries to waive COVID{{nbhyph}}19 vaccine patent rights in an effort to boost production of vaccines for poor nations.{{cite web |date=10 March 2021 |title=Rich, developing nations wrangle over COVID vaccine patents |url=https://www.reuters.com/article/us-health-coronavirus-wto-idUSKBN2B21V9 |access-date=19 June 2021| vauthors=Blenkinsop P, Maclean W, Ellis A |archive-url=https://web.archive.org/web/20210311110904/https://www.reuters.com/article/us-health-coronavirus-wto-idUSKBN2B21V9|archive-date=11 March 2021|url-status=live|website=Reuters }} On 5 May 2021, the US government under President Joe Biden announced that it supports waiving intellectual property protections for COVID{{nbhyph}}19 vaccines.{{cite web|vauthors=Macias AM, Breuninger K, Franck|date=5 May 2021|title=U.S. backs waiving patent protections for Covid vaccines, citing global health crisis|website=CNBC |url=https://www.cnbc.com/2021/05/05/us-backs-covid-vaccine-intellectual-property-waivers-to-expand-access-to-shots-worldwide.html|access-date=5 May 2021|url-status=live|archive-date=5 May 2021|archive-url=https://web.archive.org/web/20210505192749/https://www.cnbc.com/2021/05/05/us-backs-covid-vaccine-intellectual-property-waivers-to-expand-access-to-shots-worldwide.html}} The Members of the European Parliament have backed a motion demanding the temporary lifting of intellectual property rights for COVID{{nbhyph}}19 vaccines.{{cite web|vauthors=Sánchez Nicolás E|date=11 June 2021|title=Pressure builds on EU to back WTO vaccine-patent waiver |website=EUobserver |url=https://euobserver.com/coronavirus/152109|access-date=14 June 2021 |archive-date=19 October 2021|archive-url=https://web.archive.org/web/20211019023651/https://euobserver.com/coronavirus/152109|url-status=live}}

File:Brasileiro tomando vacina contra o COVID-19.jpg vaccine in Brazil in April 2021]]

In a meeting in April 2021, the World Health Organization's emergency committee addressed concerns of persistent inequity in global vaccine distribution.{{cite web|date=20 April 2021|title=WHO says against proof of Covid-19 vaccination for international travel|url=https://www.scmp.com/news/world/europe/article/3130249/who-says-against-proof-covid-19-vaccination-international-travel|access-date=17 May 2021|website=South China Morning Post|archive-date=3 May 2021|archive-url=https://web.archive.org/web/20210503215233/https://www.scmp.com/news/world/europe/article/3130249/who-says-against-proof-covid-19-vaccination-international-travel|url-status=live}} Although 9 percent of the world's population lives in the 29 poorest countries, these countries had received only 0.3% of all vaccines administered as of May 2021.{{cite news |vauthors=Goodman PS, Mandavilli A, Robbins R, Stevis-Gridneff M |date=15 May 2021 |title=What Would It Take to Vaccinate the World Against Covid? |work=The New York Times |issn=0362-4331 |url=https://www.nytimes.com/2021/05/15/world/americas/covid-vaccine-patent-biden.html |archive-url=https://web.archive.org/web/20210515193214/https://www.nytimes.com/2021/05/15/world/americas/covid-vaccine-patent-biden.html |archive-date=15 May 2021 |url-access=subscription |url-status=live |access-date=17 May 2021}} In March 2021, Brazilian journalism agency Agência Pública reported that the country vaccinated about twice as many people who declare themselves white than black and noted that mortality from COVID{{nbhyph}}19 is higher in the black population.{{cite web |vauthors=Muniz B, Fonseca B, Fernandes L, Pina R |url=https://apublica.org/2021/03/brasil-registra-duas-vezes-mais-pessoas-brancas-vacinadas-que-negras/ |date=15 March 2021 |title=Brasil registra duas vezes mais pessoas brancas vacinadas que negras|trans-title=Brazil registers twice as many white people vaccinated as black people |accessdate=28 May 2021 |archive-url=https://web.archive.org/web/20210315234311/https://apublica.org/2021/03/brasil-registra-duas-vezes-mais-pessoas-brancas-vacinadas-que-negras/|archive-date=15 March 2021|url-status=live|work=Agência Pública|language=pt-br}}

In May 2021, UNICEF made an urgent appeal to industrialized nations to pool their excess COVID{{nbhyph}}19 vaccine capacity to make up for a 125-million-dose gap in the COVAX program. The program mostly relied on the Oxford–AstraZeneca COVID‑19 vaccine produced by the Serum Institute of India, which faced serious supply problems due to increased domestic vaccine needs in India from March to June 2021. Only a limited amount of vaccines can be distributed efficiently, and the shortfall of vaccines in South America and parts of Asia is due to a lack of expedient donations by richer nations. International aid organizations have pointed at Nepal, Sri Lanka, and the Maldives, as well as Argentina, Brazil, and some parts of the Caribbean, as problem areas where vaccines are in short supply. In mid-May 2021, UNICEF was also critical of the fact that most proposed donations of Moderna and Pfizer vaccines were not slated for delivery until the second half of 2021 or early in 2022.{{cite web |url=https://www.cidrap.umn.edu/news-perspective/2021/05/un-agencies-make-urgent-appeal-covax-vaccine-doses |title=UN agencies make urgent appeal for COVAX vaccine doses |date=17 May 2021 |vauthors=Schnirring L |work=CIDRAP |access-date=15 June 2021 |archive-date=31 October 2021 |archive-url=https://web.archive.org/web/20211031100236/https://www.cidrap.umn.edu/news-perspective/2021/05/un-agencies-make-urgent-appeal-covax-vaccine-doses |url-status=live }}

File:COVID-19 mass vaccination in Ratina, Tampere, Finland.jpg

In July 2021, the heads of the World Bank Group, the International Monetary Fund, the World Health Organization, and the World Trade Organization said in a joint statement: "As many countries are struggling with new variants and a third wave of COVID{{nbhyph}}19 infections, accelerating access to vaccines becomes even more critical to ending the pandemic everywhere and achieving broad-based growth. We are deeply concerned about the limited vaccines, therapeutics, diagnostics, and support for deliveries available to developing countries."{{cite web|date=30 June 2021|title=First Meeting of the Task Force on COVID-19 Vaccines, Therapeutics and Diagnostics for Developing Countries|url=https://www.who.int/news/item/30-06-2021-first-meeting-of-the-task-force-on-covid-19-vaccines-therapeutics-and-diagnostics-for-developing-countries|access-date=5 July 2021|website=World Health Organization (WHO)|archive-date=19 October 2021|archive-url=https://web.archive.org/web/20211019012233/https://www.who.int/news/item/30-06-2021-first-meeting-of-the-task-force-on-covid-19-vaccines-therapeutics-and-diagnostics-for-developing-countries|url-status=live}}{{cite web|vauthors=Tapper J, McKie R|date=3 July 2021|title=Vaccines 'outpaced by variants', WHO warns, as Delta now in 98 countries |url=http://www.theguardian.com/society/2021/jul/03/vaccines-outpaced-by-variants-who-warns-as-delta-now-in-98-countries |access-date=5 July 2021|website=The Guardian |archive-date=21 October 2021|archive-url=https://web.archive.org/web/20211021000507/https://www.theguardian.com/society/2021/jul/03/vaccines-outpaced-by-variants-who-warns-as-delta-now-in-98-countries|url-status=live}} In July 2021, The BMJ reported that countries had thrown out over 250,000 vaccine doses as supply exceeded demand and strict laws prevented the sharing of vaccines.{{cite journal |vauthors=Mahase E |title=Covid-19: Countries dump vaccines as demand slumps and sharing proves difficult |journal=BMJ |volume=374 |pages=n1893 |date=July 2021 |pmid=34315725 |doi=10.1136/bmj.n1893 |s2cid=236457553 |title-link=doi |doi-access=free }} A survey by The New York Times found that over a million doses of vaccine had been thrown away in ten U.S. states because federal regulations prohibit recalling them, preventing their redistribution abroad.{{cite news | vauthors = Levin D |date=1 August 2021 |title=The U.S. is wasting vaccine doses, even as cases rise and other countries suffer shortages. |work=The New York Times |url=https://www.nytimes.com/2021/08/01/us/covid-us-vaccine-wasted.html |url-status=live |access-date=10 August 2021 |archive-url=https://web.archive.org/web/20210809193617/https://www.nytimes.com/2021/08/01/us/covid-us-vaccine-wasted.html |archive-date=9 August 2021}} Furthermore, doses donated close to expiration often cannot be administered quickly enough by recipient countries and end up having to be discarded.{{cite news |date=8 June 2021 |title=Covid-19 vaccines: Why some African states can't use their vaccines |work=BBC News |url=https://www.bbc.com/news/56940657 |access-date=20 August 2021 |archive-date=14 November 2021 |archive-url=https://web.archive.org/web/20211114043558/https://www.bbc.com/news/56940657 |url-status=live }} To help overcome this problem, the Prime Minister of India, Narendra Modi, announced that they would make their digital vaccination management platform, CoWIN, open to the global community. He also announced that India would also release the source code for the contact tracing app Aarogya Setu for developers around the world. Around 142 countries, including Afghanistan, Bangladesh, Bhutan, the Maldives, Guyana, Antigua and Barbuda, St. Kitts and Nevis, and Zambia, expressed their interest in the application for COVID management.{{cite news |vauthors=Das S |date=5 July 2021 |title=CoWIN goes global: India makes tech open source, 142 nations show interest |work=Business Standard India |url=https://www.business-standard.com/article/current-affairs/cowin-goes-global-india-makes-tech-open-source-142-nations-show-interest-121070501046_1.html |access-date=25 March 2022 |archive-date=25 March 2022 |archive-url=https://web.archive.org/web/20220325083051/https://www.business-standard.com/article/current-affairs/cowin-goes-global-india-makes-tech-open-source-142-nations-show-interest-121070501046_1.html |url-status=live }}{{cite press release |title=Aarogya Setu is now open source |url=https://pib.gov.in/PressReleasePage.aspx?PRID=1626979 |date=26 May 2020 |access-date=18 July 2023 |website=pib.gov.in |archive-date=26 June 2020 |archive-url=https://web.archive.org/web/20200626123003/https://pib.gov.in/PressReleasePage.aspx?PRID=1626979 |url-status=live }}

Amnesty International and Oxfam International have criticized the support of vaccine monopolies by the governments of producing countries, noting that this is dramatically increasing the dose price by five times and often much more, creating an economic barrier to access for poor countries.{{cite press release |title=G7 support for pharma monopolies is putting millions of lives at risk |date=10 June 2021 |publisher=Amnesty International |url=https://www.amnesty.org/en/latest/press-release/2021/06/g7-support-for-pharma-monopolies-putting-millions-of-lives-at-risk/ |access-date=20 August 2021 |archive-date=19 October 2021 |archive-url=https://web.archive.org/web/20211019023637/https://www.amnesty.org/en/latest/press-release/2021/06/g7-support-for-pharma-monopolies-putting-millions-of-lives-at-risk/ |url-status=live }}{{cite press release |title=Vaccine monopolies make cost of vaccinating the world against COVID at least 5 times more expensive than it could be |date=29 July 2021 |publisher=Oxfam International |url=https://www.oxfam.org/en/press-releases/vaccine-monopolies-make-cost-vaccinating-world-against-covid-least-5-times-more |access-date=20 August 2021 |archive-date=10 January 2022 |archive-url=https://web.archive.org/web/20220110095146/https://www.oxfam.org/en/press-releases/vaccine-monopolies-make-cost-vaccinating-world-against-covid-least-5-times-more |url-status=live }} Médecins Sans Frontières (Doctors without Borders) has also criticized vaccine monopolies and repeatedly called for their suspension, supporting the TRIPS waiver. The waiver was first proposed in October 2020 and has support from most countries, but was delayed by opposition from the EU (especially Germany; major EU countries such as France, Italy, and Spain support the exemption),{{cite web| vauthors=Stiglitz J |date=15 December 2021|title=If Olaf Scholz is serious about progress, he must back a patent waiver for Covid vaccines |url=https://www.theguardian.com/commentisfree/2021/dec/15/olaf-scholz-patent-waiver-covid-vaccines-germany-eu|url-status=live |access-date=15 December 2021|website=The Guardian|archive-url=https://web.archive.org/web/20211215123521/https://www.theguardian.com/commentisfree/2021/dec/15/olaf-scholz-patent-waiver-covid-vaccines-germany-eu |archive-date=15 December 2021 }} the UK, Norway, and Switzerland, among others. MSF called for a Day of Action in September 2021 to put pressure on the WTO Minister's meeting in November, which was expected to discuss the TRIPS IP waiver.{{cite web |title=Countries must not let another opportunity slip by to advance the global waiver on overcoming COVID-19 medical-tool monopolies |url=https://www.msfindia.in/countries-must-not-let-another-opportunity-slip-by-to-advance-the-global-waiver-on-overcoming-covid-19-medical-tool-monopolies/ |website=Médecins Sans Frontières (MSF)/Doctors Without Borders |access-date=23 September 2021 |date=13 September 2021 |archive-date=10 October 2021 |archive-url=https://web.archive.org/web/20211010113553/https://www.msfindia.in/countries-must-not-let-another-opportunity-slip-by-to-advance-the-global-waiver-on-overcoming-covid-19-medical-tool-monopolies/ |url-status=live }}{{cite web |title=MSF calls for no patents or profiteering on COVID-19 drugs and vaccines / No profiteering on COVID-19 drugs and vaccines, says MSF |url=https://www.msf.org/no-profiteering-covid-19-drugs-and-vaccines-says-msf |website=Médecins Sans Frontières (MSF) International |access-date=23 September 2021 |archive-date=26 November 2021 |archive-url=https://web.archive.org/web/20211126191836/https://www.msf.org/no-profiteering-covid-19-drugs-and-vaccines-says-msf |url-status=live }}{{cite web |title=Governments must act fast on consensus supporting historic move to suspend monopolies during pandemic / COVID-19: Governments must build consensus around waiver |url=https://www.msf.org/covid-19-governments-must-build-consensus-around-waiver |website=Médecins Sans Frontières (MSF) International |access-date=23 September 2021 |archive-date=23 October 2021 |archive-url=https://web.archive.org/web/20211023213012/https://www.msf.org/covid-19-governments-must-build-consensus-around-waiver |url-status=live }}

File:Iran COVID19-Vaccination center.jpg

In August 2021, to reduce unequal distribution between rich and poor countries, the WHO called for a moratorium on booster doses at least until the end of September. However, in August, the United States government announced plans to offer booster doses eight months after the initial course to the general population, starting with priority groups. Before the announcement, the WHO harshly criticized this type of decision, citing the lack of evidence for the need for boosters, except for patients with specific conditions. At this time, vaccine coverage of at least one dose was 58% in high-income countries and only 1.3% in low-income countries, and 1.14 million Americans had already received an unauthorized booster dose. US officials argued that waning efficacy against mild and moderate disease might indicate reduced protection against severe disease in the coming months. Israel, France, Germany, and the United Kingdom have also started planning boosters for specific groups.{{cite journal |date=August 2021 |title=The WHO is right to call a temporary halt to COVID vaccine boosters |journal=Nature |volume=596 |issue=7872 |pages=317 |doi=10.1038/d41586-021-02219-w|pmid=34404945 |bibcode=2021Natur.596..317. |s2cid=237199262 | title-link = doi | doi-access = free }}{{cite news |title=WHO slams wealthy nations' rush towards Covid booster shots while millions worldwide lack first jab |url=https://www.france24.com/en/europe/20210818-who-slams-wealthy-nations-rush-towards-covid-booster-shots-while-millions-worldwide-lack-first-jab |access-date=21 August 2021 |work=France 24 |agency=Agence France-Presse |date=18 August 2021 |archive-date=2 November 2021 |archive-url=https://web.archive.org/web/20211102043229/https://www.france24.com/en/europe/20210818-who-slams-wealthy-nations-rush-towards-covid-booster-shots-while-millions-worldwide-lack-first-jab |url-status=live }}{{cite news |vauthors=Kramer J |title=The U.S. plans to authorize boosters—but many already got a third dose |url=https://www.nationalgeographic.com/science/article/the-us-is-expected-to-authorize-boostersbut-many-already-got-a-third-dose |access-date=21 August 2021 |work=National Geographic |date=18 August 2021 |archive-date=10 October 2021 |archive-url=https://web.archive.org/web/20211010113551/https://www.nationalgeographic.com/science/article/the-us-is-expected-to-authorize-boostersbut-many-already-got-a-third-dose}} In September 2021, more than 140 former world leaders and Nobel laureates, including former President of France François Hollande, former Prime Minister of the United Kingdom Gordon Brown, former Prime Minister of New Zealand Helen Clark, and Professor Joseph Stiglitz, called on the candidates to be the next German chancellor to declare themselves in favor of waiving intellectual property rules for COVID{{nbhyph}}19 vaccines and transferring vaccine technologies.{{cite press release|date=14 September 2021|title=More than 140 former heads of state and Nobel laureates call on candidates for German chancellor to waive intellectual property rules for COVID-19 vaccines|url=https://www.oxfam.org/en/press-releases/more-140-former-heads-state-and-nobel-laureates-call-candidates-german-chancellor|access-date=22 September 2021|website=Oxfam International|archive-date=19 October 2021|archive-url=https://web.archive.org/web/20211019012236/https://www.oxfam.org/en/press-releases/more-140-former-heads-state-and-nobel-laureates-call-candidates-german-chancellor|url-status=live}} In November 2021, nursing unions in 28 countries filed a formal appeal with the United Nations over the refusal of the UK, EU, Norway, Switzerland, and Singapore to temporarily waive patents for COVID{{nbhyph}}19 vaccines.{{cite web|vauthors=Walker P|date=29 November 2021|title=Nursing unions around world call for UN action on Covid vaccine patents|url=https://www.theguardian.com/world/2021/nov/29/nursing-unions-around-world-call-for-un-action-on-covid-vaccine-patents|access-date=29 November 2021|website=The Guardian|archive-date=29 November 2021|archive-url=https://web.archive.org/web/20211129233801/https://www.theguardian.com/world/2021/nov/29/nursing-unions-around-world-call-for-un-action-on-covid-vaccine-patents|url-status=live}}

During his first international trip, the President of Peru, Pedro Castillo, spoke at the seventy-sixth session of the United Nations General Assembly on 21 September 2021, proposing the creation of an international treaty signed by world leaders and pharmaceutical companies to guarantee universal vaccine access, arguing that "The battle against the pandemic has shown us the failure of the international community to cooperate under the principle of solidarity."{{cite news|vauthors=Psaledakis D|date=22 September 2021|title=Developing nations' plea to world's wealthy at U.N.: stop vaccine hoarding|work=Reuters|url=https://www.reuters.com/world/developing-nations-plea-worlds-wealthy-un-stop-vaccine-hoarding-2021-09-22/|access-date=29 September 2021|archive-date=10 November 2021|archive-url=https://web.archive.org/web/20211110152208/https://www.reuters.com/world/developing-nations-plea-worlds-wealthy-un-stop-vaccine-hoarding-2021-09-22/|url-status=live}}{{cite web|author=Empresa Peruana de Servicios Editoriales S. A. EDITORA PERÚ|title=Peru: President suggests global agreement at UN ensuring universal access to vaccines|url=https://andina.pe/ingles/noticia-peru-president-suggests-global-agreement-at-un-ensuring-universal-access-to-vaccines-862568.aspx|access-date=29 September 2021|website=Andina|date=21 September 2021 |language=es|archive-date=30 October 2021|archive-url= https://web.archive.org/web/20211030162131/https://andina.pe/ingles/noticia-peru-president-suggests-global-agreement-at-un-ensuring-universal-access-to-vaccines-862568.aspx|url-status=live}}

Optimizing the societal benefit of vaccination may benefit from a strategy that is tailored to the state of the pandemic, the demographics of a country, the age of the recipients, the availability of vaccines, and the individual risk for severe disease. In the UK, the interval between prime and booster doses was extended to vaccinate as many people as early as possible.{{cite journal | vauthors = Baraniuk C | title = Covid-19: How the UK vaccine rollout delivered success, so far | journal = BMJ | volume = 372 | pages = n421 | date = February 2021 | pmid = 33602672 | doi = 10.1136/bmj.n421 | s2cid = 231946710 | title-link = doi | doi-access = free }} Many countries are starting to give an additional booster shot to the immunosuppressed{{cite web |date=13 August 2021 |title=Additional Dose of mRNA COVID{{nbhyph}}19 Vaccine for Patients Who Are Immunocompromised |url=https://www.cdc.gov/vaccines/covid-19/clinical-considerations/immunocompromised-patients.html |access-date=16 August 2021 |website=U.S. Centers for Disease Control and Prevention (CDC) |archive-date=7 October 2021 |archive-url=https://web.archive.org/web/20211007072024/https://www.cdc.gov/vaccines/covid-19/clinical-considerations/immunocompromised-patients.html |url-status=live }}{{cite web |date=4 August 2021 |title=France plans rollout of Covid vaccine booster shots – but only for the vulnerable |url=https://www.france24.com/en/europe/20210804-france-plans-rollout-of-covid-vaccine-booster-shots-%E2%80%93-so-far-only-for-the-vulnerable |access-date=16 August 2021 |website=France 24 |archive-date=22 October 2021 |archive-url=https://web.archive.org/web/20211022012337/https://www.france24.com/en/europe/20210804-france-plans-rollout-of-covid-vaccine-booster-shots-%E2%80%93-so-far-only-for-the-vulnerable |url-status=live }} and the elderly,{{cite web |date=29 July 2021 |title=Israel to offer 3rd COVID booster shot to older citizens |url=https://apnews.com/article/middle-east-health-israel-coronavirus-pandemic-775e772a7507bcab708e9eea4bdcc50a |access-date=16 August 2021 |website=Associated Press |archive-date=31 October 2021 |archive-url=https://web.archive.org/web/20211031225657/https://apnews.com/article/middle-east-health-israel-coronavirus-pandemic-775e772a7507bcab708e9eea4bdcc50a |url-status=live }} and research predicts an additional benefit of personalizing vaccine doses in the setting of limited vaccine availability when a wave of virus Variants of Concern hits a country.{{cite journal |vauthors=Hunziker P |date=July 2021 |title=Personalized-dose Covid-19 vaccination in a wave of virus Variants of Concern: Trading individual efficacy for societal benefit |url=https://precisionnanomedicine.com/article/26101-personalized-dose-covid-19-vaccination-in-a-wave-of-virus-variants-of-concern-trading-individual-efficacy-for-societal-benefit |journal=Precision Nanomedicine |volume=4 |issue=3 |pages=805–820 |doi=10.33218/001c.26101 | title-link = doi | doi-access = free |access-date=16 August 2021 |archive-date=9 October 2021 |archive-url=https://web.archive.org/web/20211009194402/https://precisionnanomedicine.com/article/26101-personalized-dose-covid-19-vaccination-in-a-wave-of-virus-variants-of-concern-trading-individual-efficacy-for-societal-benefit |url-status=live }}

Despite the extremely rapid development of effective mRNA and viral vector vaccines, vaccine equity has not been achieved. The World Health Organization called for 70 percent of the global population to be vaccinated by mid-2022, but as of March 2022, it was estimated that only one percent of the 10 billion doses given worldwide had been administered in low-income countries.{{cite web |title=UN analysis shows a link between lack of vaccine equity and widening poverty gap |url=https://news.un.org/en/story/2022/03/1114762 |website=UN News |access-date=14 April 2022 |date=28 March 2022 |archive-date=12 April 2022 |archive-url=https://web.archive.org/web/20220412221531/https://news.un.org/en/story/2022/03/1114762 |url-status=live }} An additional 6 billion vaccinations may be needed to fill vaccine access gaps, particularly in developing countries. Given the projected availability of newer vaccines, the development and use of whole inactivated virus (WIV) and protein-based vaccines are also recommended. Organizations such as the Developing Countries Vaccine Manufacturers Network could help to support the production of such vaccines in developing countries, with lower production costs and greater ease of deployment.{{cite web |title=DCVMN |url=http://www.dcvmn.org/ |website=Developing Countries Vaccine Manufacturers Network |access-date=26 April 2022 |archive-date=26 April 2022 |archive-url=https://web.archive.org/web/20220426031853/http://www.dcvmn.org/ |url-status=live }}

While vaccines substantially reduce the probability and severity of infection, it is still possible for fully vaccinated people to contract and spread COVID{{nbhyph}}19.{{cite journal |vauthors=Thompson MG, Burgess JL, Naleway AL, Tyner HL, Yoon SK, Meece J, Olsho LE, Caban-Martinez AJ, Fowlkes A, Lutrick K, Kuntz JL, Dunnigan K, Odean MJ, Hegmann KT, Stefanski E, Edwards LJ, Schaefer-Solle N, Grant L, Ellingson K, Groom HC, Zunie T, Thiese MS, Ivacic L, Wesley MG, Lamberte JM, Sun X, Smith ME, Phillips AL, Groover KD, Yoo YM, Gerald J, Brown RT, Herring MK, Joseph G, Beitel S, Morrill TC, Mak J, Rivers P, Harris KM, Hunt DR, Arvay ML, Kutty P, Fry AM, Gaglani M |date=April 2021 |title=Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers - Eight U.S. Locations, December 2020-March 2021 |url= https://www.cdc.gov/mmwr/volumes/70/wr/pdfs/mm7013e3-H.pdf |journal=MMWR Morb Mortal Wkly Rep |volume=70 |issue=13 |pages=495–500 |doi=10.15585/mmwr.mm7013e3 | title-link = doi | doi-access = free |pmc=8022879 |pmid=33793460 |access-date=9 June 2021 |archive-date=28 August 2021 |archive-url=https://web.archive.org/web/20210828063404/http://www.cdc.gov/mmwr/volumes/70/wr/pdfs/mm7013e3-H.pdf |url-status=live }} Public health agencies have recommended that vaccinated people continue using preventive measures (wear face masks, social distance, wash hands) to avoid infecting others, especially vulnerable people, particularly in areas with high community spread. Governments have indicated that such recommendations will be reduced as vaccination rates increase and community spread declines.{{cite web |date=11 February 2020 |title= When You've Been Fully Vaccinated |url= https://www.cdc.gov/coronavirus/2019-ncov/vaccines/fully-vaccinated.html |access-date=29 April 2021 | work = U.S. Centers for Disease Control and Prevention (CDC)|archive-date=28 July 2021|archive-url= https://web.archive.org/web/20210728053816/https://www.cdc.gov/coronavirus/2019-ncov/vaccines/fully-vaccinated.html |url-status=live }}

{{boxquote|text=Moreover, an unequal distribution of vaccines will deepen inequality and exaggerate the gap between rich and poor and will reverse decades of hard-won progress on human development.|source =

United Nations, COVID vaccines: Widening inequality and millions vulnerable{{cite web |title=COVID vaccines: Widening inequality and millions vulnerable |url=https://news.un.org/en/story/2021/09/1100192 |publisher=United Nations |access-date=30 October 2021 |date=19 September 2021 |archive-date=31 December 2021 |archive-url=https://web.archive.org/web/20211231032620/https://news.un.org/en/story/2021/09/1100192 |url-status=live }}|width = 33%|align = right}}

Vaccine inequity damages the global economy, disrupting the global supply chain. Most vaccines were reserved for wealthy countries; {{as of|lc=y|September 2021}}, some countries have more vaccines than are needed to fully vaccinate their populations. When people are under-vaccinated, needlessly die, experience disability, and live under lockdown restrictions, they cannot supply the same goods and services. This harms the economies of under-vaccinated and over-vaccinated countries alike. Since rich countries have larger economies, rich countries may lose more money to vaccine inequity than poor ones, though the poor ones will lose a higher percentage of GDP and experience longer-term effects.{{cite web |title=Impact of vaccine inequity on economic recovery |work=UNDP Data Futures Platform |url=https://data.undp.org/vaccine-equity/impact-of-vaccine-inequity-on-economic-recovery/ |publisher=UN Development program |access-date=30 October 2021 |archive-date=3 November 2021 |archive-url=https://web.archive.org/web/20211103211957/https://data.undp.org/vaccine-equity/impact-of-vaccine-inequity-on-economic-recovery/ |url-status=live }} High-income countries would profit an estimated US$4.80 for every $1 spent on giving vaccines to lower-income countries.{{cite journal | title = COVID-19 vaccine equity and booster doses | journal = The Lancet Infectious Diseases | volume = 21 | issue = 9 | pages = 1193 | date = September 2021 | pmid = 34391506 | pmc = 8360703 | doi = 10.1016/S1473-3099(21)00486-2 | vauthors = ((The Lancet Infectious Diseases Editors)) }}

The International Monetary Fund sees the vaccine divide between rich and poor nations as a serious obstacle to a global economic recovery.{{cite web|vauthors=Elliott L|date=5 October 2021|title=IMF cuts global economic forecast as pandemic 'hobbles' growth|url=https://www.theguardian.com/business/2021/oct/05/imf-cuts-global-economic-forecast-as-pandemic-hobbles-growth|access-date=6 October 2021|website=The Guardian|archive-date=27 October 2021|archive-url=https://web.archive.org/web/20211027083228/https://www.theguardian.com/business/2021/oct/05/imf-cuts-global-economic-forecast-as-pandemic-hobbles-growth|url-status=live}} Vaccine inequity disproportionately affects refuge-providing states, as they tend to be poorer, and refugees and displaced people are economically more vulnerable even within those low-income states, so they have suffered more economically from vaccine inequity.{{cite web |title=Refugees face dire consequences from COVID-19 underfunding, UNHCR warns |url=https://news.un.org/en/story/2021/09/1100162 |publisher=United Nations |access-date=30 October 2021 |date=17 September 2021 |archive-date=30 October 2021 |archive-url=https://web.archive.org/web/20211030015042/https://news.un.org/en/story/2021/09/1100162 |url-status=live }}

Several governments agreed to shield pharmaceutical companies like Pfizer and Moderna from negligence claims related to COVID{{nbhyph}}19 vaccines (and treatments), as in previous pandemics, when governments also took on liability for such claims.

In the US, these liability shields took effect on 4 February 2020, when the US Secretary of Health and Human Services, Alex Azar, published a notice of declaration under the Public Readiness and Emergency Preparedness Act (PREP Act) for medical countermeasures against COVID{{nbhyph}}19, covering "any vaccine, used to treat, diagnose, cure, prevent, or mitigate COVID{{nbhyph}}19, or the transmission of SARS-CoV-2 or a virus mutating therefrom". The declaration precludes "liability claims alleging negligence by a manufacturer in creating a vaccine, or negligence by a health care provider in prescribing the wrong dose, absent willful misconduct." In other words, absent "willful misconduct", these companies cannot be sued for money damages for any injuries that occur between 2020 and 2024 from the administration of vaccines and treatments related to COVID{{nbhyph}}19.{{cite web |url=https://www.phe.gov/Preparedness/legal/prepact/Pages/COVID19.aspx|title=Notice of Declaration under the Public Readiness and Emergency Preparedness Act for medical countermeasures against COVID-19 | vauthors = Azar A |date=4 February 2020 |access-date=22 April 2020|archive-url=https://web.archive.org/web/20200425015411/https://www.phe.gov/Preparedness/legal/prepact/Pages/COVID19.aspx|archive-date=25 April 2020|url-status=live}} The declaration is effective in the United States through 1{{spaces}}October 2024.

In December 2020, the UK government granted Pfizer legal indemnity for its COVID{{nbhyph}}19 vaccine.{{cite web|vauthors=Lintern S|date=2 December 2020|title=Pfizer given protection from legal action over coronavirus vaccine by UK government|url=https://www.independent.co.uk/news/health/coronavirus-pfizer-vaccine-legal-indemnity-safety-ministers-b1765124.html|access-date=8 May 2021|website=The Independent|archive-date=5 May 2021|archive-url=https://web.archive.org/web/20210505000529/https://www.independent.co.uk/news/health/coronavirus-pfizer-vaccine-legal-indemnity-safety-ministers-b1765124.html|url-status=live}}

In the European Union, the COVID{{nbhyph}}19 vaccines were granted a conditional marketing authorization, which does not exempt manufacturers from civil and administrative liability claims.{{cite web|date=11 December 2020|title=Questions and Answers: Conditional Marketing Authorisation of COVID-19 Vaccines in the EU|url=https://ec.europa.eu/commission/presscorner/detail/en/qanda_20_2390|access-date=29 December 2020|publisher=European Commission|at=Question: What is the difference in liability between EU Conditional Marketing Authorisation vs Emergency Use Authorisations?|archive-date=4 October 2021|archive-url=https://web.archive.org/web/20211004172148/https://ec.europa.eu/commission/presscorner/detail/en/qanda_20_2390|url-status=live}} The EU conditional marketing authorizations were changed to standard authorizations in September 2022.{{cite web | title=EMA recommends standard marketing authorizations for Comirnaty and Spikevax COVID-19 vaccines | website=European Medicines Agency | date=16 September 2022 | url=https://www.ema.europa.eu/en/news/ema-recommends-standard-marketing-authorisations-comirnaty-spikevax-covid-19-vaccines | access-date=7 October 2022 | archive-date=16 September 2022 | archive-url=https://web.archive.org/web/20220916095151/https://www.ema.europa.eu/en/news/ema-recommends-standard-marketing-authorisations-comirnaty-spikevax-covid-19-vaccines | url-status=live }} While the purchasing contracts with vaccine manufacturers remain secret, they do not contain liability exemptions, even for side effects not known at the time of licensure.{{cite web|vauthors=Haahr T|date=7 September 2020|title=COVID-19: MEPs want safe vaccines, full transparency and liability for companies|url=https://www.europarl.europa.eu/news/en/press-room/20200904IPR86419/covid-19-meps-want-safe-vaccines-full-transparency-and-liability-for-companies|access-date=29 December 2020|website=European Parliament|at=Ms. Gallina stressed negotiations with companies had been difficult but underlined that those companies developing and manufacturing COVID-19 vaccines would indeed be liable according to current laws, and if something goes wrong, they could be taken to court. This also goes for compensation for hidden defects.|archive-date=13 October 2021|archive-url=https://web.archive.org/web/20211013122000/https://www.europarl.europa.eu/news/en/press-room/20200904IPR86419/covid-19-meps-want-safe-vaccines-full-transparency-and-liability-for-companies|url-status=live}}

The Bureau of Investigative Journalism, a nonprofit news organization, reported in an investigation that unnamed officials in some countries, such as Argentina and Brazil, said that Pfizer demanded guarantees against costs of legal cases due to adverse effects in the form of liability waivers and sovereign assets such as federal bank reserves, embassy buildings, or military bases, going beyond what was expected from other countries, such as the US.{{cite news |date=11 March 2021 |title=Investigation: Drugmaker 'bullied' Latin American nations |work=Al Jazeera |url=https://www.aljazeera.com/news/2021/3/11/investigation-pfizer-bullied-latin-american-nations |access-date=15 June 2021 |archive-date=31 October 2021 |archive-url=https://web.archive.org/web/20211031172842/https://www.aljazeera.com/news/2021/3/11/investigation-pfizer-bullied-latin-american-nations |url-status=live }} During the pandemic parliamentary inquiry in Brazil, Pfizer's representative said that its terms for Brazil are the same as for all other countries with which it has signed deals.{{cite news |vauthors=Barcellos R |date=13 May 2021 |title=Carlos Murillo diz que cláusulas criticadas pelo Brasil valem em 110 países |language=Portuguese |trans-title=Carlos Murillo says critical clauses for Brazil are valid in 110 countries |work=CNN Brasil |url=https://www.cnnbrasil.com.br/politica/2021/05/13/carlos-murillo-diz-que-clausulas-criticadas-pelo-brasil-valem-em-110-paises |access-date=15 June 2021 |archive-date=28 June 2021 |archive-url=https://web.archive.org/web/20210628135359/https://www.cnnbrasil.com.br/politica/2021/05/13/carlos-murillo-diz-que-clausulas-criticadas-pelo-brasil-valem-em-110-paises |url-status=live }}

On 13 December 2022, the governor of Florida, Ron DeSantis, said that he would petition the state supreme court to convene a grand jury to investigate possible violations in respect to COVID{{nbhyph}}19 vaccines,{{cite web |url=https://www.flgov.com/2022/12/13/governor-ron-desantis-petitions-florida-supreme-court-for-statewide-grand-jury-on-covid-19-vaccines-and-announces-creation-of-the-public-health-integrity-committee/ |title=Governor Ron DeSantis Petitions Florida Supreme Court for Statewide Grand Jury on COVID-19 Vaccines and Announces Creation of the Public Health Integrity Committee |access-date=14 December 2022 |website=www.flgov.com |archive-date=14 December 2022 |archive-url=https://web.archive.org/web/20221214000857/https://www.flgov.com/2022/12/13/governor-ron-desantis-petitions-florida-supreme-court-for-statewide-grand-jury-on-covid-19-vaccines-and-announces-creation-of-the-public-health-integrity-committee/ |url-status=live }} and declared that his government would be able to get "the data whether they [the companies] want to give it or not".{{cite web |url=https://www.theguardian.com/us-news/2022/dec/13/ron-desantis-grand-jury-investigation-covid-vaccines-florida |title=Florida governor seeks grand jury investigation into Covid vaccines |date=13 December 2022 |access-date=14 December 2022 |website=www.theguardian.com |archive-date=13 December 2022 |archive-url=https://web.archive.org/web/20221213224924/https://www.theguardian.com/us-news/2022/dec/13/ron-desantis-grand-jury-investigation-covid-vaccines-florida |url-status=live }}

In November 2023, the US state of Texas sued Pfizer under section 17.47 of the Texas Deceptive Trade Practices Act, alleging that the company misled the public about its COVID-19 vaccine by hiding risks while making false claims about its effectiveness.{{cite news|url=https://www.reuters.com/legal/pfizer-is-sued-by-texas-over-covid-19-vaccine-claims-2023-11-30/ |title=Pfizer is sued by Texas over COVID vaccine claims| vauthors = Jonathan S |work=Reuters|date=30 November 2023}}{{Cite web|url=https://www.texastribune.org/2023/11/30/texas-attorney-general-pfizer-lawsuit/|title=Texas attorney general sues Pfizer, claiming vaccines didn't end pandemic quickly enough| vauthors = Harper KB |date=30 November 2023|website=The Texas Tribune}} In June 2024, the US state of Kansas similarly sued Pfizer under the Kansas Consumer Protection Act, making similar allegations.{{cite news | vauthors = Pierson B |date=18 June 2024 |title=Kansas accuses Pfizer of misleading public about COVID vaccine in lawsuit|url=https://www.reuters.com/legal/kansas-accuses-pfizer-misleading-public-about-covid-vaccine-lawsuit-2024-06-17|work=Reuters}}

In June 2021, a report revealed that the UB-612 vaccine, developed by the US-based Covaxx, was a for-profit venture initiated by Blackwater founder Erik Prince. In a series of text messages to Paul Behrends, the close associate recruited for the Covaxx project, Prince described the profit-making possibilities of selling the COVID{{nbhyph}}19 vaccines. Covaxx provided no data from the clinical trials on safety or efficacy it conducted in Taiwan. The responsibility of creating distribution networks was assigned to an Abu Dhabi-based entity, which was mentioned as "Windward Capital" on the Covaxx letterhead but was actually Windward Holdings. The firm's sole shareholder, who handled "professional, scientific and technical activities", was Erik Prince. In March 2021, Covaxx raised $1.35 billion in a private placement.{{cite web|url=https://www.reuters.com/business/healthcare-pharmaceuticals/exclusive-blackwater-founder-prince-takes-role-covid-vaccine-venture-2021-06-04/|title=Blackwater founder Prince takes role in COVID vaccine venture|accessdate=4 June 2021|website=Reuters|date=4 June 2021|archive-date=9 October 2021|archive-url=https://web.archive.org/web/20211009203609/https://www.reuters.com/business/healthcare-pharmaceuticals/exclusive-blackwater-founder-prince-takes-role-covid-vaccine-venture-2021-06-04/|url-status=live}}

File:202003- Cumulative county COVID-19 death rates - by share of votes for Donald Trump.svg

{{Excerpt|COVID-19 vaccine misinformation and hesitancy}}

The United States Department of Defense (DoD) undertook a disinformation campaign in the Philippines, later expanded to Central Asia and the Middle East, which sought to discredit China, in particular its Sinovac vaccine, disseminating hashtags of #ChinaIsTheVirus and posts claiming that the Sinovac vaccine contained gelatin from pork and therefore was haram or forbidden for purposes of Islamic law.{{Cite news | vauthors = Bing C, Schechtman J |date=14 June 2024 |title=Pentagon Ran Secret Anti-Vax Campaign to Undermine China during Pandemic |url=https://www.reuters.com/investigates/special-report/usa-covid-propaganda/ |work=Reuters}}

• COVID‑19 drug development
• COVID‑19 drug repurposing research

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{{refend}}

• {{cite web|title=Protocol mRNA-1273-P301|publisher=Moderna |url=https://www.modernatx.com/sites/default/files/mRNA-1273-P301-Protocol.pdf |access-date=21 September 2020 |archive-date=28 September 2020|archive-url=https://web.archive.org/web/20200928044809/https://www.modernatx.com/sites/default/files/mRNA-1273-P301-Protocol.pdf}}
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• {{cite web |title=Protocol 2019nCoV-301 |publisher=Novavax |url=https://novavax.widen.net/s/tt8xfddqvs/2019ncov_301_version_redacted}}

{{Wikiquote}}

{{Wikinews|New study analyzes the varying levels of protection offered by COVID-19 vaccines}}

• {{cite web | title=COVID-19 vaccine tracker and landscape | publisher=World Health Organization (WHO) | url=https://www.who.int/publications/m/item/draft-landscape-of-covid-19-candidate-vaccines }}
• {{YouTube|id=xpqfdr9FPWM|time=0s|title=M.I.T. Lecture 10: Kizzmekia Corbett, Vaccines}}
• {{YouTube|id=FAMFH3tHWks|time=0s|title=M.I.T. Lecture 12: Dan Barouch, Covid-19 Vaccine Development}}
• {{cite web | title=The 5 Stages of COVID-19 Vaccine Development: What You Need to Know About How a Clinical Trial Works | date=September 2020 | publisher=Johnson & Johnson | url=https://www.jnj.com/innovation/the-5-stages-of-covid-19-vaccine-development-what-you-need-to-know-about-how-a-clinical-trial-works }}
• {{cite web | title=Coronavirus vaccine – weekly summary of Yellow Card reporting | publisher=UK Medicines and Healthcare products Regulatory Agency (MHRA) | url=https://www.gov.uk/government/publications/coronavirus-covid-19-vaccine-adverse-reactions/coronavirus-vaccine-summary-of-yellow-card-reporting }}
• {{cite web | title=COVID-19 vaccine safety report - 05-10-2023 | website=Therapeutic Goods Administration (TGA) | date=4 October 2023 | url=https://www.tga.gov.au/news/covid-19-vaccine-safety-reports/covid-19-vaccine-safety-report-05-10-2023 }}
• {{cite news | title=Halting Progress and Happy Accidents: How mRNA Vaccines Were Made | work=The New York Times | date=15 January 2022 | url=https://www.nytimes.com/2022/01/15/health/mrna-vaccine.html | archive-url=https://web.archive.org/web/20220115153605/https://www.nytimes.com/2022/01/15/health/mrna-vaccine.html | archive-date=15 January 2022 | url-access=subscription | url-status=live | vauthors=Kolata G, Mueller B }}
• {{cite web | title=COVID-19 Vaccine Information Statement | date=16 October 2024 | publisher=U.S. Centers for Disease Control and Prevention (CDC) | url=https://www.cdc.gov/vaccines/hcp/vis/vis-statements/covid-19.html }}

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{{Vaccines|short=yes}}

{{#invoke:Portal bar|main|COVID-19|Medicine|Modern history|Viruses|Current events}}

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