Published on
Updated
Reading 3 mins.
Two studies published on Monday July 25 come to the same conclusion: Covid-19 infection is not responsible for the cases of unexplained hepatitis that have appeared in children in recent months. The researchers put forward another hypothesis
The cases of hepatitis which affect certain children in an unexplained way will retain their share of mystery for a little longer. Indeed, for a time suspected, the infection with Covid-19 would not ultimately be responsible for these cases having affected very young children, sometimes in a serious way.
Two scientific studies give the same conclusion
The two studies that advance these conclusions have not yet been validated by peers. Nevertheless, they rely on two main arguments to rule out Covid-19 infection as the causal element: the virus was not detected in the livers of the sick children studied, and the proportion of them presenting antibodies against Covid-19 was similar to that of children not affected by these hepatitis.
Another virus would be responsible
For the English and Scottish scientists behind these two works, it would rather be the AAV2 virus or adeno-associated virus 2, which would be responsible. Indeed, it was measured at high levels in 96% of children affected by hepatitis.
The first study, led by the MRC-University of Glasgow Center for Virus Research (CVR), looked at nine children, aged four on average, with hepatitis in Scotland. They were all hospitalized between March 14 and April 4 and remained under National Health Service care for an average of 10 days. None required a liver transplant. Their DNA was also extracted from samples of blood, liver cells, stool and throat and the results were compared with those of 58 healthy young people. AAV2 was detected in all nine hepatitis patients but in none of the control groups.
A second study points in the same direction.
The second study, led by Great Ormond Street Hospital (GOSH) and the UK Health Security Agency, looked at 28 children with hepatitis in Britain. Their analysis included liver samples from five children who needed transplants and blood samples from other youngsters who did not.
Almost all of the children tested positive for AAV2. By comparison, AAV2 was present “only very rarely” outside of this group – in just 6% of healthy children and at “much lower levels”.
And sequencing of liver samples showed that AAV2 was present and had spread through the organ.
However, this virus is known and it usually does not cause any particular pathology.
A reaction with another virus?
Scientists are suggesting a reaction with another virus, without any certainty for the moment. To explore this hypothesis, the scientists put forward the track of a co-infection of two viruses, the AAV2 virus and an adenovirus, or else with the HHV6, the herpes virus.
They believe that this is currently the best explanation for these cases of hepatitis. For Professor Deirdre Kelly, Professor of Pediatric Hepatology at the University of Birmingham, “this is a plausible explanation for these cases and it appears that co-infection plays a key role. But it is still not understood why some children develop severe cases of the disease requiring a transplant. Could one possibility be co-infection with more than a virus?“.
The different confinements in question?
Dr Antonia Ho, lead author of the studies, believes that the Covid lockdowns and restrictions have led to “a very reduced circulation of seasonal viruses”. This is what has led, according to her, to “different types of viral circulation”. A “balance” must be restored now that young people are mixing again “in a pre-pandemic way”, she insists.
Read also
Recall that just over 1,000 cases of hepatitis have been recorded in 35 countries, according to the World Health Organization, and 22 deaths. The majority of affected children are under the age of six, and about 5% of them have required liver transplants.