Question Period Note: ACUTE SEVERE HEPATITIS IN CHILDREN

Beginning in early April 2022, the World Health Organization (WHO) had reported an increase in cases of acute severe hepatitis in children not caused by known hepatitis viruses. The Public Health Agency of Canada (PHAC) is collaborating with provincial and territorial health partners across the country to investigate cases in Canada. As of May 19, 2022, 10 cases of acute severe hepatitis in children that meet the national case definition have been identified in Canada. PHAC continues to work with its provincial and territorial health partners to further investigate these cases.

• Keeping people in Canada safe from threats to their health, and keeping our most vulnerable citizens safe and healthy, is a top priority of the Government of Canada.
• The Public Health Agency of Canada is working closely with provincial and territorial health partners to further investigate cases in Canada. All provinces and territories are continuing to identify and report potential cases to the Agency so that the national scope of the investigation can be further defined.
• This is an evolving investigation, both in Canada and internationally. More information is needed to assess the situation and any potential risks to people in Canada. As the investigation evolves, the Public Health Agency of Canada will provide updates to the public.

If pressed on cases reported in the media:
• The Public Health Agency of Canada is aware the media has reported possible cases of acute severe hepatitis in children not caused by known hepatitis viruses in some jurisdictions in Canada.
• Some of these cases met the case definition and are currently included in the national investigation. Other cases are being reviewed further by provincial and territorial health partners to determine if they meet the national case definition.

If pressed on a link to COVID-19 vaccination:
• According to the World Health Organization, side effects from the COVID-19 vaccines are not suspected to be the cause of illnesses as the vast majority of affected children did not receive COVID-19 vaccination.

Investigation into acute severe hepatitis in children

On April 5, 2022, the World Health Organization (WHO) was notified of 10 cases of acute hepatitis of unknown etiology in children under 10 years of age in Scotland. Since then, further reports of cases have continued to be reported internationally, with the majority of cases to date reported from the United Kingdom. As of May 15, 2022, 429 probable cases have been reported to the WHO among children 16 years of age and younger from 22 countries. Twenty-six children have required liver transplants. At least 6 deaths have been reported to the WHO, but at least 14 deaths have been reported through country-specific reports or the media.

PHAC is working closely with provincial and territorial health partners to identify and investigate cases in Canada.

Acute severe hepatitis in children is a relatively rare condition that does occur in Canada. In many cases, an underlying or contributing cause is unknown. It is important to note that the definition being used to include cases in the national investigation is very broad. This means that any children with acute severe hepatitis (inflammation of the liver) where a cause is not certain are being included in initial investigations. Some of these children may have a diagnosis for their liver condition, but they are being included to explore possible factors that may have triggered the condition.

It is possible that additional cases will be reported. PHAC has asked provinces and territories (P/Ts) to look for patients in their jurisdictions, dating back to October 2021, to align with the timeframe identified in the WHO’s international investigation. PHAC is continuing to work with all P/Ts to identify potential cases so that the national scope of the investigation can be further defined. PHAC is also engaging with international health authorities and reporting information to the WHO.

The cause of illnesses reported internationally is unknown at this time and active investigation continues in multiple countries. Adenovirus is currently one of the hypotheses being explored. Adenovirus is a common virus that typically causes cold or flu-like illness or gastroenteritis. Investigation into other possible causes and contributing factors, such as previous COVID-19 infection, other infections, and/or environmental causes (e.g. chemicals and toxins) is continuing. According to the WHO, side effects from the COVID-19 vaccines are not suspected, as the vast majority of affected children were too young and did not receive COVID-19 vaccination.

PHAC’s involvement in the investigation

PHAC is collaborating with provincial/territorial public health partners to coordinate an investigation into potential cases of acute severe hepatitis in children not caused by known hepatitis viruses. Case definitions, case report forms, and reporting processes have been established and shared with all partners. PHAC is connecting with international health partners to collect more information about their investigations. All cases identified in Canada are being reported to the Pan-American Health Organization and the WHO.

At this time in Canada, we do not know if there has been an increase in cases of acute severe hepatitis in children not caused by known hepatitis viruses. We are currently analyzing Canadian hospitalization data to determine the number of cases that we would normally see in Canada over time. This baseline information will allow us to determine if we are seeing an increase in cases reported.

The National Microbiology Laboratory, in collaboration with the Canadian Public Laboratory Surveillance Network, has developed laboratory guidelines for testing cases of acute severe hepatitis in children not caused by known hepatitis viruses in Canada, and these have been shared with P/Ts.

Symptoms of hepatitis

Symptoms of acute severe hepatitis include jaundice (yellowing of the skin and eyes), abdominal pain, nausea, vomiting, dark urine, light-coloured stools, loss of appetite, fever, and fatigue. Even in cases where the cause of acute severe hepatitis is unknown, treatment is available, and most children recover with medical care.

Public Communication

On May 10, 2022, PHAC provided an initial media statement to several media outlets on this evolving issue. On May 20, 2022 PHAC issued an updated media statement to first report the number of cases in Canada. As the investigation evolves, PHAC will provide updates to the public.

Key Facts
• Hepatitis is a term for liver inflammation. Depending on the cause, the disease can be very sudden and progress to liver failure over a few days to weeks (called acute).
• Acute severe hepatitis in children is a relatively rare condition that does occur in Canada. In many cases, an underlying cause cannot be found. Even in cases where the cause of acute severe hepatitis is unknown, treatment is available and most children recover with medical care.
• As of May 19, 2022, 10 cases of acute severe hepatitis in children not caused by known hepatitis viruses have been identified in Canada in 4 provinces: Alberta (3), Manitoba (2), Ontario (4), and Quebec (1). The children are between 1 and 13 years of age, and became sick between November 3, 2021, and April 23, 2022. All children were hospitalized. Two children have required liver transplants. No deaths have been reported.