Adeno-associated viruses linked with development of hepatitis

Liver with hepatitis - The rise in unexplained hepatitis cases among children since 2022 has been linked to a common childhood virus, known as adeno-associated virus 2 (AAV2), by researchers at UCL and Great Ormond Street Hospital (GOSH). The study is one of three independent research papers, published in Nature and led by UCL, GOSH, the University of Glasgow and the University of California, San Francisco, respectively, that show how AAV2 can be directly implicated in disease. Since 2022, more than 1,000 cases of paediatric hepatitis (inflammation of the liver) with no known cause have been reported in 35 countries, including the UK and USA. In some cases, the hepatitis was so severe that a liver transplant was needed; meanwhile a smaller subset of cases was fatal. Previously, health officials believed that a spike in adenovirus infections - which typically cause mild cold or flu-like illness - during spring 2022, may have been part of the explanation for the outbreak of hepatitis cases. However, the three new studies show that typically 'harmless' AAV2, which cannot replicate without a 'helper' virus such as adenovirus or herpesvirus, was present in a majority of cases of unknown hepatitis. The work at UCL and GOSH led by Professor Judith Breuer (UCL Great Ormond Street Institute of Child Health), found that high levels of AAV2 were present in 27 out of 28 (96.4%) cases of hepatitis, with significantly lower levels children with adenovirus infections, (six out of 100) even if  immunocompromised (11 out of 32).