Paediatric hepatitis of unknown aetiology

05 May 2022

From October 2021 to 29 April 2022, at least 169 cases of acute hepatitis of unknown aetiology have been reported in 12 countries (predominately in Europe) in children aged from one month to 16 years of age, with most cases aged under 5 years. No cases have been identified in Australia to date.


  • Laboratory testing has ruled out hepatitis A-E viruses in all cases.
  • In the United Kingdom (UK), which has reported most cases to date, adenovirus has been detected in 40 of 53 (75%) cases tested. The UK has recently observed a significant increase in adenovirus infections in the community, following minimal circulation of adenovirus over the past two years. Adenovirus type 41F has been isolated from blood samples from several of the affected children. Adenovirus type 41F is not usually associated with acute hepatitis in immunocompetent children.
  • SARS-CoV-2 was detected in 10 of 60 cases (16%) from the UK, however, given there was a high background rate of COVID-19 at the time, this is not unexpected.
  • There is no known association with international travel.
  • No other clear epidemiological risk factors have been identified so far, and the cases remain under investigation. Testing for other infections, chemicals and toxins is underway.

Clinical features

  • The clinical syndrome is of acute hepatitis with markedly elevated transaminases, often with jaundice, and sometimes preceded by gastrointestinal symptoms.
  • Symptoms of hepatitis include fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, pale stools, joint pain, and jaundice.
  • Some cases have required treatment in specialised paediatric liver units and approximately 10% of cases have required liver transplantation. At least one death has been reported.

Medical practitioners are advised to:

  • Be alert for cases of hepatitis of unknown aetiology in children aged 16 years and younger.
  • Seek advice from a paediatric infectious diseases specialist, gastroenterologist or hepatologist regarding children presenting with compatible symptoms and signs.   
  • Consider testing children with acute hepatitis of unknown aetiology for:
    • adenovirus - PCR of whole blood (EDTA – lavender top tube), as well as urine, stool and respiratory samples
    • routine hepatitis testing (hepatitis A-E)
    • other investigations as indicated by the clinical picture.
  • Indicate test is for ‘acute hepatitis’ on laboratory request form.
  • Use standard precautions with optimal placement in a single en-suite room whilst the patient is considered infectious and until resolution of symptoms.  
  • Urgently refer any severely unwell children to the nearest emergency department which manages children.
  • Inform CDCB (1300 232 272) of all cases of children aged 16 years and younger who present with acute hepatitis with serum transaminase >500 IU/L (AST/ALT).
  • For further information see  

For all enquiries, please contact the CDCB on 1300 232 272 (24 hours/7 days) 

Dr Louise Flood – Director, Communicable Disease Control Branch