Influenza returns with a season dominated by clade 3C.2a1b.2a.2 A(H3N2) viruses, WHO European Region, 2021/22

the WHO European Region influenza surveillance network

Research output: Contribution to journalArticlepeer-review


In the WHO European Region, COVID-19 non-pharmaceutical interventions continued slowing influenza circulation in the 2021/22 season, with reduced characterisation data. A(H3) predominated and, in some countries, co-circulated with A(H1)pdm09 and B/ Victoria viruses. No B/Yamagata virus detections were confirmed. Substantial proportions of characterised circulating virus subtypes or lineages differed antigenically from their respective northern hemisphere vaccine components. Appropriate levels of influenza virus characterisations should be maintained until the season end and in future seasons, when surveillance is adapted to integrate SARS-CoV-2.

Original languageEnglish
Issue number15
Publication statusPublished - 14 Apr 2022
Externally publishedYes

Bibliographical note

Funding Information:
We express our gratitude to the TESSy data management team, especially Marius Valentin Valcu, for the technical support. We would like to thank Edoardo Colzani and Ole Heuer for reviewing the manuscript, as well as the contributors (Luca Freschi, Olov Svartstrom and Priyanka Nannapaneni, ECDC) and reviewers (Eeva Broberg, Pasi Penttinen, ECDC, Dmitriy Pereyaslov, WHO) of the 'Summary of influenza virus antigenic and genetic characterisations in Europe: data reported by influenza reference laboratories to The European Surveillance System for weeks 40/2021 to week 4/2022', for their valuable comments. We acknowledge all the members of the European region influenza surveillance network for their work on influenza surveillance data collection. We gratefully acknowledge the authors of the HA sequences retrieved from GISAID and used in this study. We would also like to acknowledge the physicians and nurses of sentinel network sites and intensive care units for their contribution in providing respiratory specimens. We would like to thank John McCauley and Rodney Daniels from the WHO CC for reference and research on influenza, Crick Worldwide Influenza Centre, The Francis Crick Institute, London, United Kingdom for their continuous tireless support to the WHO European Region influenza network.

Publisher Copyright:
© 2022 European Centre for Disease Prevention and Control (ECDC). All rights reserved.


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