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ECRAID-Base POS-Disease X

New POS-Disease X publication: Team tackles acute hepatitis mystery

An unusually high number of cases of unexplained acute hepatitis among young children has been puzzling health experts.

Published in

  • Eurosurveillance


  • Janko van Beek
  • Pieter LA Fraaij
  • Carlo Giaquinto
  • Delane Shingadia
  • Peter Horby
  • Giuseppe Indolfi
  • Marion Koopmans
  • Acute hepatitis study group

An unusually high number of cases of unexplained acute hepatitis among young children has been puzzling health experts in recent weeks. By early May 2022, the World Health Organisation (WHO) reported at least 348 cases globally, with another 70 cases under investigation. Twenty-six children required a liver transplantation and six deaths were reported.

Hepatitis is an inflammation of the liver and can be caused by viral or bacterial infections, environmental factors (i.e., toxins, medication), or metabolic, hereditary, or autoimmune diseases. The suspected outbreak of acute hepatitis among children is concerning since no causative agent or underlying disease could be identified. Researchers in the UK have detected low levels of adenovirus type F41 in 91/126 cases (72%); however, adenovirus F41 usually causes symptoms of diarrhoea and is not known to cause hepatitis among previously healthy individuals.  

Investigating the geographical spread

To help solve this mystery, the team behind the POS-ER-Disease X study took the lead in a collaboration between Ecraid, Penta – Child Health Research, International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC), European Society for Paediatric Infectious Diseases (ESPID) and European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN). Together, they developed a rapid online survey among hospitals around the world with the aim to assess the geographical spread of the suspected outbreak. The researchers collected data on the incidence of acute hepatitis among children in the last 5 years to identify countries with a recent elevation of cases.

“Unexplained acute hepatitis in paediatric patients does occur, but the high number of cases in the UK is very unusual. Countries do not usually monitor the number of cases of acute hepatitis and this study is a first attempt to rapidly assess whether the outbreak is spreading to other countries”, explained virologist Janko van Beek from the Erasmus Medical Center Rotterdam. 

Condition remains rare 

The study team found that cases seem to be elevated in five out of 17 European countries surveyed and one out of seven non-European countries compared with previous years, with the highest case numbers reported in the UK since the beginning of this year. However, the condition remains rare and while in some countries or centres there are signals for an increase in cases, this is not evident in other places. The authors note that further epidemiological, immunological and clinical studies are required to identify the cause, risk factors and progression of this ongoing outbreak.  

The results of the study by Janko van Beek (Erasmus Medical Center Rotterdam), Pieter L.A. Fraaij (Erasmus Medical Center Rotterdam), Carlo Giaquinto (University of Padova), Delane Shingadia (Great Ormond Street Hospital, London), Peter Horby (University of Oxford), Giuseppe Indolfi (University of Florence) and Marion Koopmans (Erasmus Medical Center Rotterdam) were published in Eurosurveillance on 12 May 2022. 

About POS-ER-Disease X

POS-ER-Disease X focuses on specialized infectious disease hospitals in high-density urban areas as sentinel sites for the development and deployment of an observational study using a generic clinical characterization protocol (CCP) for emerging infections. The primary objective of the study is to improve epidemic and pandemic preparedness. It is part of the ECRAID-Base project, which has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 965313.