Acute cases of hepatitis of unknown origin in children worry doctors and parents alike in April. Is there a direct connection with Sars-CoV-2 infections? Two new British studies can deny that and instead bring another virus into play.
In the spring there are a striking number of cases of hepatitis in children, which can hardly be explained with the transmission routes known to date. According to the World Health Organization, at least 1010 cases have now been identified in 35 countries. Many of those affected were under the age of five. 46 children required a liver transplant because of the severity of the disease, 22 died. Two studies by research teams from London and Glasgow are now independently investigating the same causes.
Accordingly, everything indicates that two common types of virus returned particularly violently after the end of the pandemic measures. Experts suspected early on that adenoviruses could be involved. The viruses usually cause colds. Because of the pandemic measures, however, many children were hardly able to build up immunity against them.
The studies, led by the University of Glasgow and Great Ormond Street Hospital in London, show that in most cases another common virus was also involved in the infections. Adeno-associated virus 2 (AAV2), does not normally cause disease and requires a co-infecting “helper” virus to replicate.
At least that is the current state of knowledge. According to the researchers, it is still unclear whether AAV2 is an indicator of previous adenovirus infection or an independent cause. AAV2 was present in 96 percent of cases in both studies, which combined included 37 cases in the UK and control groups. The Scottish researchers also found genetic differences in the immune systems of children who became seriously ill.
The most plausible explanation for the cases of hepatitis of unknown origin in children is a co-infection with AAV2 and either the adenovirus or, more rarely, the herpesvirus HHV6. Both studies also concluded that a link to Covid-19 is very unlikely as the rise in cases did not follow Covid-19 spikes. In addition, no evidence of Sars-CoV-2 was found in the liver, and the proportion of children who had antibodies corresponded to that of the general population.
However, further investigations are needed to prove this. Studies were published on pre-print servers prior to peer review.