A new study found that the spate of severe hepatitis cases in children from January to July 2022 has been caused by three factors, namely adenovirus, adeno-associated virus 2 (AAV2), and an underlying genetic predisposition to the disease. In a pre-print study, a team of researchers studied nine of the original hepatitis cases reported in April. They conducted a range of tests to find any new or previously undetected viruses or genetic factors that may have caused hepatitis in the children.

The team found that all nine children had been infected with the adeno-associated virus 2. Adeno-associated virus 2 belongs to a group of viruses called Dependoparvovirus which infects both humans and some primates. They also analyzed the genomes of the children to check for a common specific immune system marker called human leucocyte antigens. In the human body, immune system cells use these human leucocyte antigens to detect other viruses and pathogens and engulf them.

In the study, the researchers found that eight out of the nine children had a higher genetic prevalence of a certain type of human leucocyte antigen, which may have increased their likelihood of getting hepatitis symptoms from these viral infections. They also added that COVID-19 restrictions may have helped in increasing their susceptibility to these pathogens as many children weren’t being exposed to these viruses and developing immunity at the ages they normally should have. 

(Source: https://www.livemint.com/science/health/hepatitis-outbreak-scientists-found-possible-cause-for-mystery-outbreak-11658985957795.html )