Influenza returns with a season dominated by clade 3C.2a1b.2a.2 A(H3N2) viruses, WHO European Region, 2021/22
Angeliki Melidou, Csaba Ködmön, Karen Nahapetyan, Annette Kraus, Erik Alm, Cornelia Adlhoch, Piers Mooks, Nishi Dave, Carlos Carvalho, Margaux M. I. Meslé, Rodney S. Daniels, Richard Pebody, Members of the WHO European Region influenza surveillance network
Abstract
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.