Ontario health officials are investigating seven probable cases of severe acute hepatitis in children — including one child who was sent from CHEO to SickKids hospital in Toronto for urgent treatment last December — amid reports of clusters of cases in some parts of the world.
Officials say it is too soon to say whether there has been an increase in such cases in Canada.
“More information is needed to assess the situation and any potential risks to people in Canada,” Chief Public Health Officer Dr. Theresa Tam said in a tweet this week.
Both CHEO and SickKids are monitoring any cases of severe hepatitis of unknown origin. The seven reported this week meet the case definition and timing from Public Health Ontario for cases that require further investigation.
The World Health Organization reported this week that there are now 348 probable cases of acute hepatitis of unknown origin among children across five regions of the world. One hundred and sixty three of those cases are in the UK and the US has recently said it was investigating 109 probable cases.
Spokesperson Jessamine Luck of SickKids in Toronto said the hospital treats children with severe acute hepatitis of unknown origin every year and it remains to be seen whether the cases between Oct. 1, 2021 and April 30, 2022 under investigation represent an increase compared to previous years or whether any will be confirmed to be caused by a “novel clinical entity”.
In Ottawa, spokesman Patrick Moore said the December case, one of the seven cases reported by SickKids, is CHEO’s only suspect case.
“CHEO experts continue to work with their colleagues across the province and around the world and will report any probable cases treated locally to Ontario’s public health authorities.”
Tam said those and other cases will be reviewed by health authorities and may become part of the national investigation into the global issue.
The issue has raised concern because of the severity of the illness and apparent clusters of cases in some parts of the world. Some children have required liver transplants and there is at least one reported death.
In the US, where there has been a cluster of such cases in Alabama, the Centers for Disease Control and Prevention is looking at a common virus, adenovirus, as a possible cause, but has not yet reached any conclusions. Some have criticized the CDC for not looking more closely at COVID-19 as a cause, given the phenomenon is occurring during an unprecedented global pandemic when many children are not eligible to be vaccinated.
Experts in Ontario say there are still plenty of questions to be answered about the cases, but there is no reason for parents to panic. The cases, while serious, are extremely rare and what has been seen in Ontario in recent months does not necessarily represent anything distinctive.
Dr. Alison McGeer, an infectious disease specialist at Sinai Health in Toronto, said the clusters of cases seen in Alabama and the number of cases seen in Scotland look distinctive from what has been seen in the rest of the world. She said the cases elsewhere are not “obviously so different from baseline” although information is evolving quickly.
“There is a lot of work to be done before we have a clear idea of what is actually happening in different places in the world,” she said.
“What I am hearing about Canada so far is there is nothing that stands out as different or unusual at the moment. That doesn’t mean we haven’t had cases, it just means if we have had cases it looks like a really small number.”
Although it is early in the investigations, she said there has been a lot of adenovirus activity in recent months.
McGeer also said it is too early to rule out a connection with COVID-19, although the illnesses are clearly not related to the vaccine because most of the affected children are too young to be vaccinated.
She said it could possibly be directly related to COVID-19, adding that there doesn’t appear to be much evidence so far that it has been a factor. But it could also be connected to the pandemic in that some viruses were largely suppressed during the pandemic because of public health measures and are coming back stronger as people increase contact.
University of Ottawa virologist Earl Brown agreed that the cause remains an open question, although adenovirus 41 has been found in many of the affected children.
He speculated that the link with COVID-19 could be that it sets the groundwork for worse disease from other infections, but said there are still too many unanswered questions to point to a cause.
Physicians, meanwhile, are being told to be on the lookout for patients with signs and symptoms of hepatitis, such as recent onset jaundice, dark urine or pale stool that require further testing.