The severity of mysterious hepatitis among children “very unusual”

Cases of hepatitis of unknown origin among children have now been recorded in 20 countries in Europe. While hepatitis of unknown origin is reported every year, the severity of cases this time is “very unusual”, medical experts say. 

The news about unknown hepatitis first came from the UK, when an increase in acute hepatitis cases of unknown aetiology was reported on 5 April. 

As of 9 June 2022, 402 cases of acute hepatitis of unknown origin in children aged 16 years and below have been reported from across Europe. The vast majority are seen among children who are five years old or younger.

The UK has the highest incidence, with 224 cases. In the EU, Spain and Italy recorded the highest number of cases, each more than 30. 

So far 87 children have been admitted to an intensive care unit and 17 have received a liver transplant. On 12 May, public health authorities in Ireland announced one death associated with hepatitis of unknown origin in a child under 12 years of age.

“The severity of this is obviously very concerning, […] you wouldn’t normally see this kind of progression of the disease for sure,” Cary James, chief executive at The World Hepatitis Alliance, told EURACTIV. 

Philippa Easterbrook, technical lead of the incident team at World Health Organisation headquarters told a summit on hepatitis that while some cases of hepatitis of unknown origin are reported every year, “in terms of how worried we should be about this outbreak, it’s the first time so many cases of severe acute hepatitis have been seen”.

She added that “a proportion of cases have developed liver failure, required transplantation or resulted in death. It has to be taken seriously. An important step at the moment is to understand its cause”. 

Slow path towards elimination of viral hepatitis in Europe

Despite the UN aiming to eliminate viral hepatitis by 2030, a report published on Wednesday (15 June) has found that around a quarter of EU/EEA countries don’t have action plans or strategies for the prevention and control of the disease. 

The cause remains unknown

Commenting on the reasons for this spread, James said scientists “still haven’t really figured out what exactly is going on. Which is really unfortunate”. 

Hepatitis is an inflammation of the liver usually caused by a viral infection or excessive drinking of alcohol. There are several common types, such as A, B, C, D and E, all of which have varying levels of contagion or cause, but these common viruses from A to E have not been detected in any of these cases. 

“It could be a new virus, it could be just a form of liver disease caused by something else,” James said.

Several hypotheses are being studied to understand the cause of this hepatitis in these children. Adenovirus remains one of the main suspects, as it has been the most frequently detected virus in samples tested in the UK.

“The current leading hypotheses concern adenovirus involvement, possibly with a cofactor that is triggering a more severe infection or immune-mediated liver damage, or that measures during the COVID-19 pandemic have resulted in lack of exposure for the youngest age group and increased susceptibility,” said a report by the European Centre for Disease Control (ECDC). 

A link to the COVID-19 vaccine is considered unlikely as most cases have been unvaccinated.

The disease pathogenesis and routes of transmission remain unknown. The cases appear to be unrelated, with very few being epidemiologically linked.

“While the risk for further spread cannot be accurately assessed, as some cases have required liver transplantation, the potential impact for the affected paediatric population is considered high,” the ECDC report said. 

Adenovirus, COVID-19 examined as possible cause for mysterious hepatitis

As acute hepatitis cases of unknown origin continue to grow across the globe, the investigation into its origin is ongoing. While the leading hypothesis is adenovirus, the link to COVID-19 is also being looked at. 

The likelihood of developing hepatitis remains low

In the meantime, Sophia Makki, incident director at UK Health Security Agency, said the “likelihood of children developing hepatitis remains extremely low”.

She added that it is important to maintain normal hygiene measures, “including making sure children regularly wash their hands properly, to reduce the spread of many common infections, including adenovirus”.

The symptoms reported so far, as described by the ECDC, include “markedly elevated transaminases, often presenting with jaundice, sometimes preceded by gastrointestinal symptoms including vomiting as a prominent feature, in children up to the age of 16 years”.

“We continue to remind everyone to be alert to the signs of hepatitis – particularly jaundice, look for a yellow tinge in the whites of the eyes – and contact your doctor if you are concerned,” Makki said.

ECDC: Around 95 cases of mysterious child hepatitis in 15 EU countries

Fifteen EU countries have reported cases of acute hepatitis of unknown origin in children, while health authorities continue trying to figure out the cause.

[Edited by Alice Taylor/Zoran Radosavljevic]

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