Cases of acute and severe hepatitis of unknown origin have been reported in children in Canada and around the world

Cases of acute and severe hepatitis of unknown origin have been reported in children in Canada and around the world

The exterior of the Hospital for Sick Children in Toronto, on January 21, 2021.Fred Lom/The Globe and Mail

Canadian health officials who are investigating several cases of severe acute hepatitis of unknown origin in children say there is no evidence yet that the cases represent an increase or a departure from what is seen in a typical year.

They are advising parents to be aware, but not alarmed, as the World Health Organization (WHO) confirms about 350 cases globally, with deaths reported in the United States and Indonesia.

“It’s important to stress that at every major children’s hospital, it’s not uncommon to see cases like this,” said Vicki Ng, a pediatric gastroenterologist at the Hospital for Sick Children in Toronto, better known as SickKids. “The significance is that, given that some of them have been serious, as reported in the global literature, this is why this is under investigation.”

SickKids identified seven cases of children with severe acute hepatitis of unknown origin, consistent with the World Health Organization’s definition of a probable case, between October 1, 2021 and April 30, 2022. All seven cases are “okay” and none are currently in hospital, Dr. Ng said.

Public Health Canada, through the Canadian National Public Health Intelligence Platform, on April 14 alerted provinces and territories to increase vigilance of acute hepatitis of unknown origin in children. On Tuesday, the agency said it was not yet known if there had been an increase in such cases. British Columbia investigated one possible case that turned out to be unrelated.

The World Health Organization was first notified on 5 April of 10 cases of the disease in children under the age of 10 in central Scotland. By 8 April, 74 cases had been identified in the UK.

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There are now 348 probable cases globally, with an additional 70 cases awaiting confirmation, Philippa Easterbrook, a senior scientist with the World Health Organization’s Global Hepatitis Program, said Tuesday. Twenty countries have reported probable cases, she said, 13 other countries are investigating those cases and only six countries have reported more than five cases.

Hepatitis A to E viruses were excluded after laboratory testing and investigations are ongoing. Symptoms of the disease include jaundice and digestive problems. Some cases have required conversion to specialized pediatric liver units, and as of April 8, six children have undergone liver transplants, according to the World Health Organization. The United States has reported five deaths, and India three.

The UK had reported about 163 probable cases as of Tuesday, and Britain’s Health Security Agency was leading and coordinating investigations with nation states, Dr Easterbrook said.

“At the moment, the main hypotheses remain those involving the adenovirus,” she said at a WHO press conference in Geneva. “But, I think, there is still an important consideration about the role of COVID as well, either as a co-infection or as a pre-infection.”

Dr Easterbrook said that of the cases tested in the UK, about 70 per cent of cases were found to be positive for adenovirus, with one type – type F 41 – being the most prevalent.

Upton Allen, chief of infectious diseases at SickKids, noted that adenovirus can lie dormant in the body long after infection without a problem.

“If you get seriously ill, if your immune system is shocked for any reason, the virus may have woken up, you may detect it in your blood, and you may think it is the cause of your illness, but it is not,” he said. “So, this is something we try to come up with and evaluate carefully, until we have a clear understanding of whether the adenovirus was an innocent bystander who just woke up, or whether it was the culprit.”

Dr. Allen said all seven children are being tested for adenovirus, but he was unable to confirm on Tuesday how many children have tested positive for the virus.

Dr Easterbrook said examination of tissue samples over the past week in the UK did not show typical features one might expect of hepatitis due to adenovirus, but experts are waiting for more tests for biopsies.

Dr Easterbrook said testing for COVID-19 had found 18 per cent of UK cases were PCR-positive, and the focus next week would be on serological testing for previous exposure and infections.

Dr Allen said there is no evidence yet that adenoviruses or COVID-19 are “smoke weapons” in the cases currently under investigation.

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2022-05-11 00:50:05

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