Two scientific studies shed new light Monday on mysterious cases of hepatitis, a serious inflammation of the liver, which has affected very young children in many countries in recent months but has so far remained unexplained.
Just over 1,000 cases have been recorded in 35 countries, according to the World Health Organization, and 22 deaths. Most of the affected children are under the age of six and about 5% of them have required liver transplants.
Both studies, which have not yet been peer-reviewed, concluded that a Covid-19 infection was not to blame. The coronavirus was not detected in the livers of the sick children studied, and the proportion of them who had antibodies against Covid-19 was similar to that of children not affected by these hepatitis.
These studies, by scientists in Scotland and England respectively, point to another culprit: a common virus called AAV2 (adeno-associated virus 2), detected at elevated levels in sick children. This virus is not normally known to cause illness.
Still several gray areas
It cannot replicate itself and needs another virus for this, an adenovirus or, more rarely, the herpes virus (HHV6). Researchers believe that coinfection of two viruses (AAV2 and an adenovirus, or HHV6) is currently the best explanation for these cases of hepatitis.
“I think this is a plausible explanation for these cases,” Deirdre Kelly, a professor of pediatric hepatology at the University of Birmingham, who was not involved in these studies, said in a statement. “It seems that coinfection plays a key role.”
“But why some children develop severe cases of the disease that require a transplant is not yet understood. Could coinfection with more than one virus be a possibility?” she added.
Scientists also do not clearly understand why these cases are appearing just now. One hypothesis is that the confinements linked to the coronavirus have had an influence, for example, by modifying the usual circulation of other viruses, or by preventing children from creating certain defenses against viruses that they have faced less.
Source: BFM TV
