UK experts believe they have pinpointed the cause of the recent spate of mysterious childhood hepatitis cases around the world.
Research suggests that two common viruses returned after the pandemic lockdowns ended and triggered the rare but very serious cases of hepatitis.
Some of the children, including 12 in the UK, have required life-saving liver transplants.
The two teams of researchers, from London and Glasgow, say that babies exposed later than normal, due to Covid restrictions, lost some early immunity against:
- adenoviruses, which normally cause colds and upset stomachs
- adeno-associated virus two, which does not normally cause disease and requires a co-infecting “helper” virus, such as adenovirus, to replicate
That could explain why some developed unusual and worrying liver complications.
It’s not clear why some develop liver inflammation, but genetics could play a role.
Scientists have ruled out any connection to the coronavirus or covid vaccines.
One of the researchers, Professor Judith Breuer, a virology expert at University College London and Great Ormond Street Hospital, said: “During the lockdown period, when children were not mixing, they were not transmitting viruses to each other.”
“They weren’t developing immunity to the common infections that they would normally encounter.
“When the restrictions were lifted, kids started mixing, viruses started circulating freely, and suddenly they were exposed with this lack of previous immunity to a whole battery of new infections.”
Experts are hopeful that the cases are now less and less, but they are still on alert for new ones.
Professor Emma Thomson, who led the research from the University of Glasgow, said there were still many unanswered questions. “Larger studies are urgently needed to investigate the role of AAV2 in pediatric hepatitis.
“We also need to understand more about the seasonal circulation of AAV2, a virus that is not routinely monitored; it may be that a peak in adenovirus infection has coincided with a peak in AAV2 exposure, leading to an unusual manifestation of hepatitis in susceptible young children.”
