As of 23 April 2022, 11 European countries and the US have reported at least 169 cases of sudden onset hepatitis in children under the age of 16-years, with most cases in the UK.[1] The common hepatitis causing viruses, A, B, C, D and E, were excluded in all 169 cases.[1] Most did not have a fever, and many presented with diarrhoea, vomiting and abdominal pain, before finding raised levels of liver enzymes in their blood and jaundice.[1] According to the WHO, "It is not yet clear if there has been an increase in hepatitis cases, or an increase in awareness of hepatitis cases that occur at the expected rate but go undetected."[1] The WHO confirmed one child death, 17 liver transplantations and that the youngest child affected was a one-month-old.[1] At least 74 tested positive for adenovirus, 20 that were tested were positive for SARS-CoV-2, and of those tested 19 were detected with both a SARS-CoV-2 and adenovirus co-infection.[1] Most affected children had not received a COVID-19 vaccine.[1] The WHO's report of 23 April confirmed that 114 have been reported in the UK and Northern Ireland, 13 in Spain, 12 in Israel, nine in the US, six in Denmark, less than five in Ireland, four in The Netherlands, four in Italy, two in Norway, two in France, one in Romania, and one in Belgium.[1] The WHO has initiated an investigation into the outbreaks.[11]