Acute hepatitis of unknown etiology in children: Two studies shed light

Two scientific studies today shed new light on the cases of acute hepatitis of unknown etiology in young children that have been detected in several countries in recent months.

Just over 1.000 cases of acute hepatitis of unknown etiology have been recorded in 35 countries, according to the World Health Organization (WHO), and 22 deaths. The majority of children affected were under the age of six, and about 5% of them required a liver transplant.

The two studies, which have not yet been peer-reviewed, conclude that infection with COVID-19. The new coronavirus was not detected in the livers of the sick children whose cases were examined by the researchers and the percentage of those who showed antibodies against COVID-19 was similar to that of children not affected by acute hepatitis of unknown etiology.

These investigations, conducted respectively by scientists in Scotland and England, point to another culprit: a common virus called AAV2 (adeno-associated virus), which was detected at high levels in the children who became ill. This virus does not usually cause illness.

The virus cannot reproduce on its own and needs another virus for this, an adenovirus, or more rarely the herpes virus (HHV6).

Researchers believe that co-infection with two viruses (AAV2 and an adenovirus or HHV6) currently provides the best explanation for these hepatitis cases.

"I think it's a plausible explanation for these cases," said Neirdre Kelly, professor of pediatric hepatology at the University of Birmingham, who was not involved in the research, in a statement. "It seems that co-infection plays a key role," he added.

"But we still don't understand why some children develop severe forms of the disease that require a transplant. One possibility could be a co-infection with more than one virus?” he continued.

Scientists also do not clearly understand why these outbreaks are occurring now. One hypothesis is that pandemic lockdowns may have played a role, for example by altering the normal circulation of other viruses or preventing children from developing defenses against viruses they were not often exposed to.

Source: RES-EAP