ECDC - WHO Regional Office for Europe Hepatitis of Unkwons Origin In Children Surveillance Bulletin

Summary

This report provides an overview of the cases of hepatitis of unknown origin in children aged 16 years and below reported to ECDC and the WHO Regional Office for Europe through The European Surveillance System (TESSy) hosted at ECDC.

As of 30 June 2022, 473 cases of acute hepatitis of unknown aetiology have been reported by 21 countries: (Austria (three), Belgium (14), Bulgaria (one), Cyprus (two), Denmark (seven), France (seven), Greece (11), Ireland (16), Israel (five), Italy (35), Latvia (one), Luxembourg (one), the Netherlands (15), Norway (five), Poland (10), Portugal (19), Republic of Moldova (one), Serbia (one), Spain (40), Sweden (11), and the United Kingdom (268)).

Since the last surveillance bulletin, which used data as of 17 June 2022, 27 new cases have been reported from 10 countries (France (one), Greece (two), Ireland (two), Italy (two), Luxembourg (one), Poland (two), Portugal (four), Spain (three), Sweden (two), and the United Kingdom (eight)). Two cases (France (one), and Sweden (one)) previously classified as probable were subsequently discarded. One case (Sweden) previously discarded was reclassified as probable. Two cases (United Kingdom) previously reported were not included in the latest data update.

The epicurve shows cases by date of onset when available (294 cases), and date of hospitalisation (159 cases), or date used for statistics when the former two are not available (20 cases). The number of cases reported increased sharply starting in week 12 and remained stable between 26 and 39 cases per week up to and including week 18. As severe hepatitis can take some time to develop following the initial symptoms, and since investigations are required to rule out known causes, there is an expected reporting delay. The recent decrease in cases is therefore challenging to interpret.

The majority (76.1%) of cases are five years old or younger.

Of the 473 probable cases, 302 have information available on clinical outcome. Of these, 221 have recovered, 80 remain under medical care, and one death has been associated with this disease.

Of 295 cases with available information, 87 (29.5%) required admission to an intensive care unit. Of the 242 cases for which this information is available, 20 (8.3%) have received a liver transplant.

Overall, 364 cases were tested for adenovirus by any specimen type and had a valid positive or negative result. Of these, 192 (52.7%) tested positive. The positivity rate was the highest in whole blood specimens (53.7%). Typing data are only available for eight cases: type 31 (n = 1), type 40 (n = 1), type 41 (n = 3), and type other (n = 3).

Of the 322 cases PCR tested for SARS-CoV-2, 35 (10.9%) were positive. Serology results for SARS-CoV-2 are only available for 61 cases, of which 39 (63.9%) resulted positive. Of the 113 cases with data on COVID-19 vaccination, 97 (85.8%) were unvaccinated.

Introduction

This report provides an overview of the cases of hepatitis of unknown origin in children aged 16 years and below reported to ECDC and the WHO Regional Office for Europe for the period up to 30 June 2022, through The European Surveillance System (TESSy). Figures and tables describe national case-based data for surveillance of hepatitis of unknown origin in children aged 16 years and below from all the countries and areas of the WHO European Region, including the 27 countries of the European Union (EU) and the additional three countries of the European Economic Area (EEA). Since the first alert launched by the UK on 5 April 2022, cases of hepatitis of unknown aetiology in children have been reported from multiple countries worldwide. It is not yet clear whether all cases identified following the alert are part of a true increase compared to the baseline rate of hepatitis of unknown aetiology in children. The aetiology and pathogenetic mechanisms of disease are still under investigation. A possible association with current adenovirus infection has been identified, but other hypotheses and possible co-factors are under investigation. Most cases continue to be reported as sporadic, unrelated cases. Data are submitted through the case-based record type NOVHEP to The European Surveillance System (TESSy) database hosted at ECDC. The next update of this bulletin will be published 29 July and monthly thereafter.

Key indicators

Information on date of onset of illness was available for 294 cases. For those where this information was missing we used date of hospitalisation (159 cases) or ‘Date used for statistics’ which is a date variable defined by the country (20 cases). While ECDC does not have information on how this date is defined it may for example correspond to date of reporting to the national authorities.

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Users are advised to interpret all data with caution and be aware of their limitations. Case counts and their corresponding data may have weekly updates that include historical corrections as new information is collected and reported.

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Suggested citation: European Centre for Disease Prevention and Control/WHO Regional Office for Europe. Hepatitis of Unknown Aetiology in Children, Joint Epidemiological overview, 30 June, 2022.

Tables and figures should be referenced: European Centre for Disease Prevention and Control/WHO Regional Office for Europe. Hepatitis of Unknown Aetiology in Children, Joint Epidemiological overview, 30 June, 2022.

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