Guidance for diagnostic testing of cases with severe acute hepatitis of unknown aetiology in children

An increase in severe acute hepatitis cases of unknown aetiology among children with no underlying conditions was first reported by the United Kingdom (UK) on 5 April 2022. Testing excluded viral hepatitis types A, B, C, D and E and other known common and uncommon infectious and non-infectious causes of acute hepatitis. Following this alert, the United States and several EU/EEA and other countries have reported suspected cases. As of 19 May 2022, 303 cases have been reported in the EU/EEA and the wider WHO European region. The UK Health Security Agency (UK-HSA) published a technical briefing on 19 May 2022, and findings from their investigations have informed this technical guideline [1-3]. The clinical presentation in most of the cases is that of severe acute hepatitis requiring hospitalisation, with jaundice and markedly elevated liver transaminases. Countries in the EU/EEA and wider WHO European region report cases to The European Surveillance System (TESSy). As of18 May 2022, 276 cases were reported (including 144 cases from the UK). Of 156 cases with information, 22 (14.1%) were admitted to an intensive care unit. Of the 117 cases for which this information was available, 14 (12%) have received a liver transplant. One death has been associated with this disease. Epidemiological and laboratory investigations, including toxicological analysis, of suspected cases are still ongoing to help determine the underlying aetiology and the actual increased incidence of hepatitis in different countries. ECDC has published a rapid risk assessment [4] on this incident outlining the current knowledge and working hypotheses. Based on the findings from the UK-HSA technical briefing, adenovirus infection represents an important element of the aetiological pathway. Of note, adenovirus detection has been superior in whole blood compared to serum or plasma [3]. tested positive. rate UK-HSA