More than 1,000 children in 35 countries have developed an unidentified type of severe acute hepatitis – or inflammation of the liver – since the first case was reported in January 2022.
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British scientists say they have identified the likely cause of a recent outbreak of a mysterious liver disease affecting young children around the world.
New research suggests that a lack of exposure to two common viruses during the Covid-19 pandemic may have increased the chances of children becoming critically ill with acute hepatitis.
In studies published tuesdaytwo research teams from University College London and the University of Glasgow have said lockdown restrictions may have led some infants to lack early immunity to both adenovirus and novel adeno-associated virus 2 ( AAV2).
Crucially, both teams said they found no evidence of a direct link between the spike in hepatitis cases and infection with SARS-CoV-2, the cause of Covid-19.
More than 1,000 children in 35 countries have developed an unidentified type of severe acute hepatitis — or inflammation of the liver — since the first case was reported in January.
The majority of cases were in children aged five or younger, although diagnoses were detected in children aged under 16.
Adenovirus, which typically causes a mild cold or flu-like illness, was previously thought to be partly responsible for the mysterious outbreak, as it was the most common virus found in samples from affected children.
However, the new research indicated that adeno-associated virus 2, which normally causes no disease and cannot replicate without a “helper” virus such as adenovirus or herpesvirus, was present in 96% of cases. of unknown hepatitis examined in both studies.
Researchers now say that co-infection with the two viruses – AAV2 and an adenovirus, or less commonly the herpesvirus HHV6 – may offer the best explanation for the recent outbreak.
“While we still have unanswered questions about what exactly led to this spike in acute hepatitis, we hope these results can reassure parents concerned about Covid-19 as none of the teams found a direct link. with SARS-CoV-2 infection,” Professor Judith said. Breuer, UCL GOS Institute of Child Health, said in the report.
Typically, children are exposed to – and immune to – adenoviruses and other common diseases during their early childhood years. However, pandemic restrictions largely limited this early exposure.
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The findings add to the theories of some health experts that Covid lockdowns have reduced public immunity to a number of common illnesses. The researchers added that there was no link to coronavirus vaccines.
Both studies were conducted independently and simultaneously using UK samples. Dr Sofia Morfopoulou, a professor at UCL’s GOS Institute of Child Health, said further research was now needed to compare their findings with cases of acute hepatitis identified in other countries.
“International collaborations to further and elucidate the role of AAV2 and co-infecting viruses in pediatric unexplained hepatitis in patients from different countries are now needed,” she said.