Yanukovych Raiva | Eyem | Getty Images Scientists in the United Kingdom say they have identified the possible cause of a recent outbreak of a mysterious liver disease afflicting 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 seriously ill with acute hepatitis. In studies published on Tuesday, two research teams from University College London and the University of Glasgow said lockdown restrictions could have led some infants to lose early immunity to both adenovirus and the newly related adenovirus 2 ( AAV2). Importantly, both groups said they found no evidence of a direct link between the rise in hepatitis cases and SARS-CoV-2 infection, the cause of Covid-19.
Viral infections
More than 1,000 children in 35 countries have developed an unknown 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 have been made in children as young as 16. Adenovirus, which usually causes a mild cold or flu-like illness, was previously thought to be partly responsible for the mysterious outbreak, as it was the most commonly detected virus in samples from affected children. However, the new research showed that adeno-associated virus 2, which normally does not cause disease and cannot reproduce without a “helper” virus such as adenovirus or herpes virus, was present in 96% of cases of unknown hepatitis that were examined in both studies.
A mystery solved?
Researchers now say that co-infection with the two viruses — AAV2 and an adenovirus, or less commonly HHV6 — could provide the best explanation for the recent outbreak. “While we still have some unanswered questions about what exactly led to this outbreak of acute hepatitis, we hope these results can reassure parents concerned about Covid-19 as neither group has found a direct link with SARS-CoV-2 infection,” said Professor Judith. Breuer, UCL GOS Institute of Child Health, said in the report. Typically, children acquire exposure—and immunity—to adenoviruses and other common diseases during early childhood. However, pandemic restrictions have greatly limited this early exposure. Eric Lalmand | Afp | Getty Images The findings add to the theories of some health experts that Covid lockdowns have reduced public immunity to a number of common diseases. The researchers added that there is no link to the coronavirus vaccines. The two studies were conducted independently and concurrently using UK samples. Dr Sofia Morfopoulou, 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 are now needed to further investigate and clarify the role of AAV2 and co-infecting viruses in pediatric unexplained hepatitis in patients from different countries,” he said.
