The European Centre for Disease Prevention and Control (ECDC) periodically publishes influenza characterisation reports, giving an overview of circulating influenza viruses. These reports provide details on current vaccine strains, summarise the development of viruses since the last report and closely follow the main developments for the ongoing influenza season.
On 7 December 2021, the ECDC published the second virus characterisation period report for the 2021 to 2022 influenza season. As of week 47 of 2021, 2,707 influenza detections across the World Health Organization (WHO) European Region have been reported. Of these, 93% were type A viruses, with A(H3N2) dominating over A(H1N1)pdm09, and 7% were type B viruses, with two having been ascribed to a lineage (B/Victoria). This represents an increase in detections compared to the 2020 to 2021 season, following a large increase in the number of samples tested, and is close to the more usual number of detections seen in earlier influenza seasons.
Source: ECDC, 7 December 2021