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Liver disease outbreak: What we know so far in Canada and globally


Since early April, health officials around the world have been on alert for healthy, young children suddenly developing severe cases of hepatitis with no known cause.

According to the latest estimates by the European Centre for Disease Prevention and Control (ECDC) and the World Health Organization (WHO), there are at least 194 probable and confirmed cases reported around the world, excluding an unknown number of potential cases in Canada.

Here is what we know so far about these cases.


Hepatitis is an inflammation of the liver. The organ can become damaged or inflamed as a result of a virus, heavy alcohol consumption, toxins, some medications or another health condition. The liver serves numerous essential functions and acts like a filter for the blood that leaves the stomach and intestines. It regulates chemical levels in the blood, creates nutrients, carries away waste, helps fight infections and more.

Acute hepatitis is when the liver function is impaired for less than six months. Chronic hepatitis is when the inflammation lasts longer. Some cases of hepatitis can be severe – even fatal – if left untreated. Other cases can be mild and require no treatment.

What makes these cases of acute hepatitis unusual is that doctors have not determined their cause.


Medical officials have said that a number of cases began with gastrointestinal symptoms such as stomach pains, diarrhea and vomiting. The children later exhibited signs of jaundice, where the skin and whites around the eyes turn yellow. Jaundice is an indication that something is wrong with the liver, and medical advice should be sought immediately.

Other common symptoms of hepatitis include fever, fatigue, loss of appetite, nausea, dark urine, light-coloured stools and joint pain.

Dr. Deirdre Kelly, professor of paediatric hepatology at the University of Birmingham, told CTV News on Tuesday that the majority of children have spontaneously recovered.

“While this is a serious disease if their child develops it, the chances are they will recover on their own,” she said.


Based on numbers compiled by the ECDC in a report on April 28 and the WHO on April 23, there are at least 194 cases so far of hepatitis with no known cause in countries including the U.K., Spain, Israel, the U.S., Denmark, Ireland, the Netherlands, Italy, Norway and France.

As of April 21, 114 cases were from the U.K., according to the WHO. As of April 27, there were “approximately 55 probable and confirmed cases” from a dozen countries within the European Union and European Economic Area, 12 cases from the U.S., and another 12 out of Israel,” the ECDC said. Japan has reported one case.

“The severe hepatitis for which there is no cause, we rarely see more than about 20, 25 max in the whole year. And we’ve seen 114 in the first three to four months of this year,” Kelly said.

“These are perfectly normal children. They’ve got no comorbidities and no other infections and they’re developing severe hepatitis, of which 10 per cent have required liver transplantation.”

The 10 per cent figure is based on an earlier tally of cases from the WHO on April 23 that found 17 children required a liver transplant. One child in Britain reportedly died.

The hepatitis cases involve children between the ages of one month and 16 years, health agencies have said, with the majority occurring in young children between the ages of two and five.

Scotland’s public health agency was the first to raise the alarm about these unusual hepatitis cases in early April, after one child became sick in January and nine others in March. All were severely ill and had to be taken to the hospital where they were diagnosed with hepatitis.

The majority of similar U.S. cases were found in nine previously healthy children between the ages of one and six from Alabama. Two of the children reportedly required liver transplants. Five children with significant liver injury of unknown origin, including some experiencing acute liver failure, were admitted at a children’s hospital in Alabama as early as October 2021.

Two additional severe cases were also flagged in North Carolina and three in Illinois, with local media reporting that one resulted in a liver transplant and two others being placed on a transplant list.


While there are no confirmed cases in Canada, the Public Health Agency of Canada (PHAC) had previously told CTV News that it was “aware of reports of severe acute hepatitis of unknown origin in young children in Canada.”

“[PHAC] is working with its international partners as well as provincial and territorial partners to gather information on this evolving situation,” the agency told CTV News in an email statement on Friday.

“Potential cases in Canada are being investigated further to determine if they are related to cases in the United Kingdom and the United States.”


Health authorities are investigating a number of possible causes for these hepatitis cases. So far, the WHO has ruled out the viruses that cause hepatitis A, B, C, D and E, based on laboratory testing.

While toxin exposure is another consideration, experts believe this is less likely due to the cases being documented in different countries. Health authorities have also not found any links to international travel among the cases either.

Currently, investigations suggest a link to an adenovirus, according to the WHO and ECDC. Adenoviruses make up a large family of viruses that can spread from person to person, causing a range of illnesses including colds, pinkeye and gastroenteritis. Officials say there has been a recent rise in adenovirus infections, particularly in the U.K.

Close to half of the hepatitis cases, including those in Alabama, have been tied to an adenovirus, with lab tests indicating some children were infected with type 41, which is associated with gastroenteritis, causing diarrhea and vomiting. At least 19 cases also involved a SARS-CoV-2 co-infection.

“While adenovirus is currently one hypothesis as the underlying cause, it does not fully explain the severity of the clinical picture,” the WHO said in its April 23 report. The health agency noted this particular virus has not previously been tied to hepatitis, adding that it is a common pathogen that usually causes self-limited infections.

COVID-19 is also being considered, although a number of the cases did not involve a previously known infection.

“We don’t really know the causes yet and COVID may be implicated in some cases,” Dr. Simon Taylor-Robinson, a professor and liver researcher at London’s Imperial College, previously told CTV’s Your Morning.

“In fact, we know COVID can cause inflammation in any part of the body, not just the lungs.”

Another theory being considered is that children’s immune systems, weakened during pandemic lockdowns and distancing, may be more vulnerable to other diseases.

It is also possible that two viruses working “in concert” with each other could also be behind the hepatitis cases, some health experts say. Researchers are also exploring the possibility that the adenovirus may have mutated.


Despite disinformation being spread on social media suggesting a link between the hepatitis cases and COVID-19 vaccinations, health authorities have definitively ruled out COVID-19 vaccinations as a potential cause because they say the vast majority of cases involve children who are too young to be eligible for vaccinations.

“None of the currently confirmed cases in the U.K. has been vaccinated,” a representative of the U.K. Health Security Agency told Reuters. “There is no link to the COVID-19 vaccine.”


Adenoviruses are spread through close personal contact like touching, through the air by coughing and sneezing, or by touching contaminated objects and surfaces and then touching areas of the face before washing your hands. In some cases, it can also spread through an infected person’s stool, according to the U.S. Centers for Disease Control and Prevention (CDC).

Everyday measures, such as hand washing and general good hygiene measures, along with those adopted during the pandemic should help, experts say, adding that suddenly developing a severe case of hepatitis with no known cause is still rare despite the current global cases.

“They should (be) reassured it's relatively unusual in normal children, and good hand hygiene as we've all been used to in the COVID pandemic, and good general hygiene in the home should be sufficient," according to Kelly.

With files from CTV National News reporter Vanessa Lee, Reuters, and The Associated Press Top Stories

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