British researchers uncover a possible cause of mysterious cases of hepatitis affecting young children, finding that the serious liver condition was linked to co-infection of two common viruses, but not the coronavirus.
The World Health Organization (WHO) has reported at least 1,010 possible cases, including 46 who need a transplant You 22 deaths From illness since last October.
in Spain, 40 cases of acute hepatitis Unknown origin in children according to Europe’s Centers for Disease Prevention and Control (ECDC) and the Regional Office of the World Health Organization (WHO).
Previous theories focused on the spike in adenovirus infections commonly found behind cases.
but in two new studies Conducted independently and simultaneously in Scotland and London, the scientists found that another virus, AAV2 (adeno-associated virus 2), played an important role and was present in 96% of all patients examined.
AAV2 is generally not known to cause disease and cannot replicate itself without the presence of another ‘helper’ virus.
Both teams concluded that association with AAV2 and an adenovirus, or sometimes with the herpesvirus HHV6, offered the best explanation for severe liver disease.
Presence of AAV2 virus associated with unexplained hepatitis in children
“The presence of the AAV2 virus is associated with unexplained hepatitis in children,” said in a statement Professor of Infectious Diseases Emma Thomson from the University of Glasgow, who led the Scottish work.
But he also cautioned that it was not yet clear whether AAV2 was causing the disease or a biomarker of an underlying adenovirus infection, which is more difficult to detect but is the main pathogen.
Both studies looked at both patients who had hepatitis and those who did not, and found that AAV2 was mostly present in those who had the disease, not in those who did not.
The Scottish study also looked at the genes of children who became ill and those who did not, focusing on differences in their human leukocyte antigens, which may explain why some are more sensitive than others.
Both teams ruled out recent or previous SARS-CoV-2 infection as a direct cause.
No coronavirus was found in the patients’ livers, and although a Scottish study found that two-thirds of patients had coronavirus antibodies, the rate was similar to the general population prevalence in children at the time.
It is not clear why hepatitis cases have increased recently, but both teams highlighted the possibility that the lockdown may have contributed, either by lowering children’s immunity or by changing the pattern of circulation of the virus.
Deirdre Kelly, Professor of Pediatric Hepatology at the University of Birmingham, who was not involved in the work, said: “I think this is a plausible explanation for these cases. Coincidence seems to be the key.”
However, he added, further work is needed. for understanding Why some children develop severe disease and need a transplant.
Thomson said it was “important to understand more about the seasonal circulation of AAV2, a virus that is not routinely monitored.”
“It may be that the peak of adenovirus infection coincides with the peak of AAV2 exposure, leading to abnormal expression of hepatitis in susceptible young children.”