China News Service, April 26. According to WHO's official website, as of April 21, at least 169 cases of acute hepatitis of unknown origin have been reported in many countries, and adenovirus has been found in at least 74 cases.
The UK was the first to report a significant increase in associated acute hepatitis cases, usually in healthy, young children.
In its risk assessment, the WHO noted that adenovirus is currently considered a hypothesis of etiology, but this cannot fully explain the severity of clinical symptoms.
Other influencing factors, such as the reduced level of adenovirus transmission during the COVID-19 pandemic, the increased susceptibility of young children, the possible emergence of a new type of adenovirus, and co-infection with SARS-CoV-2, also require further study.
Furthermore, since the vast majority of affected children are not vaccinated against COVID-19, hypotheses about side effects of the COVID-19 vaccine are not currently supported.
WHO is closely monitoring the situation and working with relevant parties including UK health authorities.