2022 hepatitis of unknown origin in children

A probable case as defined by the ECDC and WHO, is a person 16 years old or younger since 1 October 2021, who presents with an acute hepatitis that tests negative for hepatitis viruses A, B, C, D and E, and has a higher than 500 IU/L of the liver enzyme aspartate transaminase.{{cite web |title=Epidemiological update: Hepatitis of unknown aetiology in children |url=https://www.ecdc.europa.eu/en/news-events/epidemiological-update-hepatitis-unknown-aetiology-children |website=European Centre for Disease Prevention and Control |access-date=13 May 2022 |language=en |date=11 May 2022}} Hepatitis due to drug toxicity, and inherited metabolic disorders, or autoimmune disorders are not included. Worldwide, not all countries may have used the same criteria.

From October 2021 to February 2022, nine children, all at the Children's of Alabama hospital, were identified with severe hepatitis of unknown origin.{{cite web |author= |url=https://www.cdc.gov/media/releases/2022/s0421-hepatitis-alert.html |title=CDC Alerts Providers to Hepatitis Cases of Unknown Origin|website=Centers for Disease Control and Prevention |access-date=25 April 2022 |language=en-us |date=21 April 2022|archive-url=https://web.archive.org/web/20220425154939/https://www.cdc.gov/media/releases/2022/s0421-hepatitis-alert.html|archive-date=25 April 2022}} All were previously healthy and the CDC was notified in November.{{cite web |title=Health Alert Network (HAN): Recommendations for Adenovirus Testing and Reporting of Children with Acute Hepatitis of Unknown Etiology |url=https://emergency.cdc.gov/han/2022/han00462.asp |website=emergency.cdc.gov |publisher=Centers for Disease Control and Prevention |access-date=25 April 2022 |language=en-us |date=21 April 2022|archive-url=https://web.archive.org/web/20220425160522/https://emergency.cdc.gov/han/2022/han00462.asp|archive-date=25 April 2022}}

On 31 March 2022, Public Health Scotland (PHS) were notified of five children aged three-to-five-years that were diagnosed with severe hepatitis of unknown origin at the Royal Hospital for Children.{{cite journal |last1=Marsh |first1=Kimberly |last2=Tayler |first2=Rachel |last3=Pollock |first3=Louisa |last4=Roy |first4=Kirsty |last5=Lakha |first5=Fatim |last6=Ho |first6=Antonia |last7=Henderson |first7=David |last8=Divala |first8=Titus |last9=Currie |first9=Sandra |last10=Yirrell |first10=David |last11=Lockhart |first11=Michael |last12=Rossi |first12=Maria K. |last13=Phin |first13=Nick |title=Investigation into cases of hepatitis of unknown aetiology among young children, Scotland, 1 January 2022 to 12 April 2022 |journal=Eurosurveillance |pages=2200318 |language=en |doi=10.2807/1560-7917.ES.2022.27.15.2200318 |pmid=35426362|date=14 April 2022|volume=27 |issue=15 |pmc=9012090 |s2cid=248180709 }} On 5 April, the International Health Regulations (IHR) National Focal Point (NFP) for the UK informed the WHO of 10 cases of sudden severe hepatitis of unknown origin in children across Scotland, one whose symptoms began in January while the others first became unwell in March.{{cite web |title=Acute hepatitis of unknown aetiology – the United Kingdom of Great Britain and Northern Ireland |url=https://www.who.int/emergencies/disease-outbreak-news/item/acute-hepatitis-of-unknown-aetiology---the-united-kingdom-of-great-britain-and-northern-ireland |website=www.who.int |access-date=25 April 2022 |archive-url=https://web.archive.org/web/20220425112703/https://www.who.int/emergencies/disease-outbreak-news/item/acute-hepatitis-of-unknown-aetiology---the-united-kingdom-of-great-britain-and-northern-ireland |archive-date=25 April 2022 |language=en}} They were previously healthy.{{cite web |title=Update: Hepatitis of unknown origin in children |url=https://www.ecdc.europa.eu/en/news-events/update-hepatitis-unknown-origin-children |website=European Centre for Disease Prevention and Control |access-date=24 April 2022 |language=en |date=19 April 2022}} By 8 April 2022, 74 cases had been identified in the UK, with six requiring a liver transplantation.{{cite web |title=Increase in hepatitis (liver inflammation) cases in children under investigation |url=https://www.gov.uk/government/news/increase-in-hepatitis-liver-inflammation-cases-in-children-under-investigation |website=GOV.UK |access-date=13 May 2022 |language=en}} Subsequently, a few cases were reported in Ireland and Spain. By 21 April, there were 114 cases in the UK.[https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1071198/acute-hepatitis-technical-briefing-1_4_.pdf "Investigation into acute hepatitis of unknown aetiology in children in England: Technical briefing"]. UK Health Security Agency. 25 April 2022. p. 3

By 23 April 2022, 11 European countries and the US had reported at least 169 cases of sudden onset hepatitis in children under the age of 16-years, with most cases in the UK.{{cite web |title=Multi-Country – Acute, severe hepatitis of unknown origin in children |url=https://www.who.int/emergencies/disease-outbreak-news/item/multi-country-acute-severe-hepatitis-of-unknown-origin-in-children |website=www.who.int |access-date=24 April 2022 |archive-url=https://web.archive.org/web/20220424173700/https://www.who.int/emergencies/disease-outbreak-news/item/multi-country-acute-severe-hepatitis-of-unknown-origin-in-children|archive-date=24 April 2022|language=en}} The common hepatitis causing viruses, A, B, C, D and E, were excluded in all 169 cases. Most did not have a fever, and many presented with diarrhoea, vomiting and abdominal pain, before finding raised levels of liver enzymes in their blood and jaundice. According to the WHO, "It is not yet clear if there has been an increase in hepatitis cases, or an increase in awareness of hepatitis cases that occur at the expected rate but go undetected." The WHO confirmed one child death, 17 liver transplantations and that the youngest child affected was one month old. At least 74 tested positive for adenovirus, 20 that were tested were positive for SARS-CoV-2, and of those tested 19 were detected with both a SARS-CoV-2 and adenovirus co-infection. Most affected children had not received a COVID-19 vaccine. The WHO's report of 23 April confirmed that 114 have been reported in the UK and Northern Ireland, 13 in Spain, 12 in Israel, nine in the US, six in Denmark, less than five in Ireland, four in the Netherlands, four in Italy, two in Norway, two in France, one in Romania, and one in Belgium. The WHO initiated an investigation into the outbreaks.{{Cite web |last=Mitropoulos |first=Arielle |date=2022-04-28 |title=Concerning clusters of severe hepatitis cases in children being investigated |url=https://abcnews.go.com/Health/clusters-severe-hepatitis-cases-children-investigated/story?id=84379149 |access-date=2022-04-29 |website=ABC News |language=en}}

By 25 April 2022 most cases were confirmed as under the age of five-years and 10 had required a liver transplantation. There were no deaths in the UK. On 26 April 2022, the Public Health Agency of Canada announced it was investigating reports of the disease affecting children in the country. The Guardian also reported that cases have been reported from countries in Asia; specifically in Japan, where a child was flagged for the disease on April 21, and in Singapore, on April 30.{{Cite web |date=April 27, 2022 |title=Global mystery hepatitis outbreak spreads to Asia and Canada |url=https://www.theguardian.com/technology/2022/apr/27/global-mystery-hepatitis-outbreak-spreads-to-asia-and-canada |access-date=April 27, 2022 |website=The Guardian}}{{Cite web |last=Pelley |first=Lauren |date=April 26, 2022 |title=Severe hepatitis of 'unknown origin' in children being investigated in Canada |url=https://www.cbc.ca/news/health/liver-disease-mystery-1.6431872 |access-date=April 27, 2022 |website=CBC News}}{{Cite web |date=April 30, 2022 |title=Infant with acute hepatitis of unknown cause hospitalised at KKH; MOH investigating |url=https://www.straitstimes.com/singapore/infant-with-acute-hepatitis-of-unknown-cause-warded-at-kkh-moh-investigating |access-date=April 30, 2022 |website=The Straits Times}} On 30 April 2022, Singapore's Ministry of Health reported that a 10-month old infant with acute hepatitis of unknown cause was hospitalised on 25 April.{{Cite web |author=卢慧菁 |date=2022-04-30 |title=本地一10月大男婴 罹患原因不明急性肝炎 |url=https://www.zaobao.com.sg/realtime/singapore/story20220430-1268133 |archive-url=https://web.archive.org/web/20220430154532/https://www.zaobao.com.sg/realtime/singapore/story20220430-1268133 |archive-date=2022-04-30 |access-date=2022-04-30 |publisher=联合早报 |language=zh-sg}}

As of 1 May 2022, the WHO had received reports of at least 228 probable cases from 20 countries, with over 50 cases under investigation.{{Cite news |last= |date=2022-05-03 |title=At least 228 probable cases of child hepatitis so far: WHO |language=en |work=Reuters |url=https://www.reuters.com/business/healthcare-pharmaceuticals/least-228-probable-cases-child-hepatitis-so-far-who-2022-05-03/ |access-date=2022-05-05}} On 2 May 2022, Indonesia's Ministry of Health reported that 3 children died of acute hepatitis in April 2022.{{cite news |date=2022-05-01 |title=Masyarakat Agar Waspada Setelah 3 Pasien Anak Dengan Hepatitis Akut Meninggal Dunia |language=id |work=Sehat Negeriku |publisher=Indonesian Ministry of Health |url=https://sehatnegeriku.kemkes.go.id/baca/rilis-media/20220501/3939769/masyarakat-agar-waspada-setelah-3-pasien-anak-dengan-hepatitis-akut-meninggal-dunia/ |access-date=2022-05-24}}{{Cite news |date=2022-05-02 |title=Three Children Died of Acute Hepatitis in Indonesia Last Month |language=en |work=Bloomberg.com |url=https://www.bloomberg.com/news/articles/2022-05-02/three-children-died-of-acute-hepatitis-in-indonesia-last-month |access-date=2022-05-02}} On 6 May 2022, Malaysia reported a case of hepatitis of unknown origin in a 4-year-old boy who sought treatment in March 2022 and subsequently underwent liver transplantation.{{Cite news |date=2022-05-06 |title=Malaysia Suspects Hepatitis Case Of Unknown Origin In Sabah Child |language=en |work=CodeBlue |url=https://codeblue.galencentre.org/2022/05/06/malaysia-suspects-hepatitis-case-of-unknown-origin-in-sabah-child/ |access-date=2022-05-06}} Also on 6 May, the CDC said that it is investigating 109 children with hepatitis of unknown origin, including five recorded deaths. More than 90% of the children were hospitalized and 14% received a liver transplant due to liver failure. The majority of children have recovered. As of 11 May, the EDCP estimated around 450 reported cases worldwide.{{cite web |last1=Crist |first1=Carolyn |title=CDC Updates Guidelines for Hepatitis Outbreak Among Children |url=https://www.medscape.com/viewarticle/973893 |website=Medscape |access-date=13 May 2022 |archive-url=https://web.archive.org/web/20220513101536/https://www.medscape.com/viewarticle/973893 |archive-date=13 May 2022 |language=en |date=12 May 2022|url-access=subscription}}

Those affected by the disease experience the following symptoms:{{Cite web |last=Mahr |first=Krista |date=2022-05-06 |title=CDC investigating more than 100 children with hepatitis of unknown cause |url=https://www.politico.com/news/2022/05/06/cdc-investigation-children-hepatitis-00030757 |access-date=2022-05-07 |website=Politico |language=en}}{{Cite web |last=Rettner |first=Rachael |date=2022-04-28 |title=Mysterious hepatitis outbreak in children: What we know |url=https://www.livescience.com/hepatitis-outbreak-kids-facts |access-date=2022-04-29 |website=Live Science |language=en}}

• Nausea
• Abdominal pain
• Vomiting
• Diarrhea
• Jaundice

File:Adenovirus 4.jpg of two adenovirus particles]]

The cause of the outbreak remains unknown. The leading hypothesis is a link to human adenovirus infection,Gurdasani D, Trent M, Ziauddeen H, Mnatzaganian E, Turville S, Chen X, Kunasekaran MP, Chughtai AA, Moa A, McEniery J, Greenhalgh T, MacIntyre CR. Acute hepatitis of unknown aetiology in children: evidence for and against causal relationships with SARS-CoV-2, HAdv and AAV2. BMJ Paediatr Open. 2024 Dec 9;8(1):e002410. {{doi|10.1136/bmjpo-2023-002410}} particularly serotype F41.{{cite journal | doi=10.1111/apa.16685 | title=Multi-country outbreak of severe acute hepatitis of unknown origin in children, 2022 | date=2023 | last1=Ilic | first1=Irena | last2=Ilic | first2=Milena | journal=Acta Paediatrica | volume=112 | issue=6 | pages=1148–1156 | pmid=36705335 | s2cid=256303849 }} As of May 2022, laboratory testing showed infection with human adenovirus in about three quarters of cases.{{cite journal | doi=10.3390/healthcare10060973 | doi-access=free | title=Hepatitis of Unknown Origin and Etiology (Acute non HepA-E Hepatitis) among Children in 2021/2022: Review of the Current Findings | year=2022 | last1=Sallam | first1=Malik | last2=Mahafzah | first2=Azmi | last3=Şahin | first3=Gülşen Özkaya | journal=Healthcare | volume=10 | issue=6 | page=973 | pmid=35742029 | pmc=9222544 }} This serotype has previously been associated with gastrointestinal symptoms, but not hepatitis. This suggests there is an additional co-factor at play.{{cite journal | doi=10.1016/j.jhep.2022.05.001 | title=The recent outbreak of acute severe hepatitis in children of unknown origin – what is known so far | year=2022 | last1=Mücke | first1=Marcus Maximilian | last2=Zeuzem | first2=Stefan | journal=Journal of Hepatology | volume=77 | issue=1 | pages=237–242 | pmid=35533802 | s2cid=248613117 | doi-access= }}

In August 2022, 9 children in a U.S. case series of hepatitis of unknown cause{{Cite journal |last1=Gutierrez Sanchez |first1=L. Helena |last2=Shiau |first2=Henry |last3=Baker |first3=Julia M. |last4=Saaybi |first4=Stephanie |last5=Buchfellner |first5=Markus |last6=Britt |first6=William |last7=Sanchez |first7=Veronica |last8=Potter |first8=Jennifer L. |last9=Ingram |first9=L. Amanda |last10=Kelly |first10=David |last11=Lu |first11=Xiaoyan |display-authors=6 |date=2022-07-13 |title=A Case Series of Children with Acute Hepatitis and Human Adenovirus Infection |journal=New England Journal of Medicine |volume=387 |issue=7 |language=en |pages=620–630 |doi=10.1056/NEJMoa2206294 |pmid=35830653 |pmc=9808750 |s2cid=250529116 |issn=0028-4793 }} and 27 of 30 children in a U.K. case series with hepatitis of unknown cause who underwent molecular testing{{Cite journal |last1=Kelgeri |first1=Chayarani |last2=Couper |first2=Michael |last3=Gupte |first3=Girish L. |last4=Brant |first4=Alexandra |last5=Patel |first5=Mitul |last6=Johansen |first6=Lauren |last7=Valamparampil |first7=Joseph |last8=Ong |first8=Evelyn |last9=Hartog |first9=Hermien |last10=Perera |first10=M.T.P.R. |last11=Mirza |first11=Darius |display-authors=6 |date=2022-07-13 |title=Clinical Spectrum of Children with Acute Hepatitis of Unknown Cause |journal=New England Journal of Medicine |volume=387 |issue=7 |pages=611–619 |doi=10.1056/NEJMoa2206704 |pmid=35830627 |s2cid=250528150 |issn=0028-4793|doi-access=free }} tested positive for human adenovirus 41 in a sample. It remained unclear, however, whether human adenovirus 41 was the cause.

One possibility is that restrictions imposed during the COVID-19 pandemic led to young children being exposed to adenovirus at a later point than normal in their lives, leading to a stronger immune response.[https://www.bbc.co.uk/news/health-61220518 Adenovirus probable cause of mysterious child hepatitis.] BBC News, 25 April 2022. Retrieved 25 April 2022. The increased susceptibility to a gut-tropic adenovirus amongst young children could be a consequence of a lower level of respiratory adenovirus circulation in the last 2 years.

Another co-factor might be prior or concurrent infection with COVID-19{{cite journal | doi=10.4254/wjh.v15.i3.364 | doi-access=free | title=May 2022 acute hepatitis outbreak, is there a role for COVID-19 and other viruses? | date=2023 | last1=Elbeltagi | first1=Reem | last2=Al-Beltagi | first2=Mohammed | last3=Saeed | first3=Nermin Kamal | last4=Bediwy | first4=Adel Salah | last5=Toema | first5=Osama | journal=World Journal of Hepatology | volume=15 | issue=3 | pages=364–376 | pmid=37034240 | pmc=10075009 }} or to another virus or environmental agent. No notable exposures relating to travel, parental occupation, diet, exposure to animals or to toxicants have been recorded in association with cases to date. Another suggestion is that there has been a change in the genetic make-up of adenovirus, so that it causes liver inflammation more readily, although data is lacking to support this.

According to the WHO, these theories require further investigation.

No link to COVID-19 or other vaccinations, which use adenovirus as a vaccine vector has been seen, particularly since the majority of cases occurred in an age group of children which were not vaccinated against COVID-19.{{Cite web |title=Multi-Country – Acute, severe hepatitis of unknown origin in children |url=https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON376 |access-date=2022-05-06 |website=www.who.int |language=en}} This observation almost excludes the possibility of COVID-19 vaccination playing a role in the outbreak.{{Cite web |title=Coronavirus disease (COVID-19): Vaccines |url=https://www.who.int/news-room/questions-and-answers/item/coronavirus-disease-(covid-19)-vaccines |access-date=2022-05-06 |website=www.who.int |language=en}}{{cite journal | doi=10.3390/healthcare10060973 | doi-access=free | title=Hepatitis of Unknown Origin and Etiology (Acute non HepA-E Hepatitis) among Children in 2021/2022: Review of the Current Findings | date=2022 | last1=Sallam | first1=Malik | last2=Mahafzah | first2=Azmi | last3=Şahin | first3=Gülşen Özkaya | journal=Healthcare | volume=10 | issue=6 | page=973 | pmid=35742029 | pmc=9222544 }}

• Gastrointestinal disease

{{Reflist}}

• {{cite web |title=Acute hepatitis of unknown aetiology (disease outbreak news)|url=https://www.who.int/emergencies/emergency-events/item/2022-e000081 |website=www.who.int |access-date=25 April 2022 |language=en}}
• {{cite web |title=Increase in hepatitis (liver inflammation) cases in children under investigation |url=https://www.gov.uk/government/news/increase-in-hepatitis-liver-inflammation-cases-in-children-under-investigation#full-publication-update-history |website=GOV.UK |access-date=3 May 2022 |language=en}}

Category:21st century in health

Category:Hepatitis outbreaks

Category:2022 disease outbreaks