Virus Characteristics

Details of the distribution of viruses detected in sentinel-source specimens can be found in the Primary care data section.


Non-sentinel virological data

Please refer to the Figures below for additional information on non-sentinel specimens tested for influenza viruses for these weeks.

Genetic characterization

Please refer to the Table below for additional information on viruses that have been characterised genetically.


ECDC published the March virus characterization report that describes the available data from circulating viruses this influenza season: currently type A influenza virus circulation is dominating over type B, due mainly to A(H3) viruses. Vaccination remains the best protective measure for prevention of influenza. However, based on post-infection ferret antisera data, the predominant A(H3N2) viruses in circulation are not well recognized by antisera raised against viruses genetically and antigenically similar to the vaccine virus, indicating antigenic diversity. Therefore, it is possible that the A(H3) vaccine component may induce less good recognition of the prevalent A(H3) viruses, although preliminary VE data indicates a still moderate level of protection against laboratory confirmed infection. Clinicians should therefore consider early antiviral treatment of at-risk groups with influenza infection, according to local guidance, to prevent severe outcomes.


This and previously published influenza virus characterization reports are available on the ECDC website.


Antiviral susceptibility of seasonal influenza viruses

Between weeks 31 and 35/2022, 4 viruses were assessed for susceptibility to neuraminidase inhibitors and 4 were assessed for susceptibility to baloxavir marboxil. Phenotypically and genotypically, no markers associated with reduced susceptibility were identified.


* The administrative boundaries include spatial feature for Kosovo, this designation being without prejudice to position on status, and is in line with United Nations Security Council Resolution 1244 (1999) and the International Court of Justice Opinion on the Kosovo Declaration of Independence.