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 25 January 2022, the ECDC published the third virus characterisation period report for the 2021 to 2022 influenza season. As of week 52 of 2021, 23,246 influenza detections across the World Health Organization (WHO) European Region had been reported. Of these, 96% were type A viruses, with A(H3N2) dominating over A(H1N1)pdm09, and 4% were type B viruses, with 13 having been ascribed to a lineage, one of which was B/Yamagata. This represents an increase of 5,601% in detections compared to the 2020-2021 season, on the back of an increase in the number of samples tested, and is closer to the more usual number of detections seen at this time in earlier seasons.
Source: ECDC, 25 January 2022