Seven probable cases of hepatitis in children reported by SickKids Hospital

The Public Health Agency of Canada says it is too early to tell if new hepatitis cases are part of the global outbreak thought to be connected to adenovirus.

Emma Jones 5 minute read May 11, 2022
Liver operation puzzle

Hepatitis refers to inflammation of the liver, reports Johns Hopkins University. GETTY

Seven probable cases of hepatitis in young children have been reported by SickKids Hospital in Toronto, however, the Public Health Agency of Canada says it is still too early to determine if this is an increase in the number of cases reported at this time each year.

Since the end of April, the Hospital for Sick Children has reported seven cases of hepatitis of unknown origin identified between Oct. 1, 2021 and April 30, 2022. A spokesperson for the Public Health Agency of Canada (PHAC) said in a statement to Healthing that while the group is aware of the hepatitis cases at The Hospital for Sick Children, they cannot yet say if these cases constitute an outbreak.

“At this time, we do not know if we are seeing an increase in the number of cases of acute hepatitis of unknown cause in children,” reads the statement. “More information is needed to assess the situation and any potential risks to people in Canada. We are working closely with provincial, territorial, and international partners on this evolving event.”

A statement from SickKids hospital says physicians are remaining vigilant and watching for symptoms of hepatitis that would require further testing. The group is also “recommending a lower threshold for referral for specialist care.” However, they also reaffirmed it is too early to tell if these cases are part of the global uptick in hepatitis cases.

“Every year, SickKids sees patients with severe acute hepatitis of unknown origin who, like the rest of our patient population, may come from across Ontario and Canada,” reads the statement. “It remains to be seen whether this number represents an increase in cases of unknown origin compared to similar time periods in previous years or if any of these cases will be confirmed to be caused by a novel clinical entity.”

The WHO originally shared news of an outbreak regarding severe liver disease of “unknown aetiology” in Great Britain and Northern Ireland on April 15. As of Tuesday, the WHO is reporting 348 probable cases and 70 additional cases under investigation, in five regions throughout the world. Only six countries are reporting more than five cases, with the U.K. reporting the majority of cases (163). At least 17 children have required a liver transplant and one child has died from the condition.

Before the announcement by the WHO, on April 14, PHAC alerted provincial and territorial public health agencies to monitor for cases of severe acute hepatitis of unknown origin in young children. The group says they will continue to monitor the situation and provide updates as they come available.

Common symptoms include diarrhea, nausea

Symptoms of acute hepatitis include fever, fatigue, nausea, vomiting, yellowing of the skin and eyes (jaundice), dark urine, abdominal pain, loss of appetite and light-coloured stools, according to PHAC.

An investigation by the UK Health Security Agency (UKHSA), Public Health Scotland, Public Health Wales and the Public Health Agency, found cases are mostly occurring in young children under the age of five. Common initial symptoms include gastroenteritis illness (diarrhea and nausea), followed by jaundice.

Children under five years of age are not yet eligible for the COVID vaccine in the U.K. and none of the children tested were vaccinated, leading the groups to say there is no evidence of a link to the COVID vaccine.

Hepatitis outbreak in children may be linked to adenovirus

In the U.K., investigators believe that this onslaught of cases is related to adenovirus, common viruses that can cause fevers, sore throats, pneumonia, diarrhea, and pink eye.

“Our investigations continue to suggest that there is an association with adenovirus and our studies are now testing this association rigorously,” Dr. Meera Chand, director of clinical and emerging infections at the U.K. Health Security Agency (UKHSA) said in a news release. “We are also investigating other contributors, including prior SARS-CoV-2.”

Investigators say adenovirus strain 41 could be the culprit. This strain is known to cause gastroenteritis and is a “a prominent cause of diarrhea and diarrhea-associated mortality in young children worldwide,” according to Science Advances.

Hepatitis refers to inflammation of the liver, reports Johns Hopkins University, and is usually caused by one of the hepatitis viruses (hepatitis A-E), genetics, exposure to drugs, alcohol or other chemicals, or an autoimmune disorder.

Unclear how adenovirus is linked to hepatitis in children

Adenovirus has been detected in roughly 70 per cent of cases tested, although researchers are also considering previous COVID-19 illnesses. Around 18 per cent of cases were also positive for SARS-CoV-2, with the WHO explaining this week the focus will be on examining tissue and blood samples for evidence of previously having the virus.

How adenovirus is linked to these cases of hepatitis condition is unclear.

“None of [the tissue and liver samples] show any of the typical features you might expect with a liver inflammation due to adenovirus,” Philippa Easterbrook, Senior Scientist in the Global Hepatitis Programme with the WHO told reporters at a news briefing. “We are awaiting further examinations of biopsies.”

Researchers say the link could be due to a number of possibilities. Because children haven’t been exposed to many different viruses and germs through the pandemic, suddenly being exposed to adenovirus may lead to a more intense immune response than would otherwise occur. Another possibility is the evolution of a new adenovirus that may cause the liver to become inflamed.

Scientists are also searching to understand if a previous COVID-19 infection followed by infection with adenovirus could lead to liver inflammation.

This article is an update on a previous story published 2022-04-27.

Emma Jones is a multimedia editor with Healthing. You can reach her at or on Instagram and Twitter @jonesyjourn.


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