Weekly influenza update, week 15, April 2018
In collaboration with WHO Regional Office for Europe, ECDC monitors and reports on influenza activity in Europe on a weekly basis throughout the flu season.
Influenza viruses continued to circulate in the Region with 26% of the individuals sampled from primary healthcare settings testing positive, while all countries reported low or medium intensity of activity of respiratory infections.
Both influenza virus types A and B were co-circulating with the majority being type A viruses.
2017/18 season overview
- Influenza has been circulating widely in the Region since week 52/2017, based on increased proportions of sentinel specimens testing positive for influenza viruses in all countries of the Region up to week 15, which is longer than in recent seasons and may contribute to the severity of this season.
For the Region overall, the majority of influenza viruses detected were type B, representing a high level of circulation of influenza B viruses compared to recent seasons. B/Yamagata lineage viruses have greatly outnumbered those of the B/Victoria lineage. Click here for more information
Different patterns of dominant type and A subtypes were observed between the countries of the Region. By week 15, influenza A viruses were dominant in several eastern European countries.
Of the type A virus detections from sentinel sources, the majority of which were subtyped, A(H1N1)pdm09 viruses have outnumbered A(H3N2) viruses. In non-sentinel sources, similar numbers of A(H3N2) viruses and A(H1N1)pdm09 viruses were reported. Click here for more information
While low in number, 55% of characterized A(H3N2) viruses belong to clade 3C.2a, 42% to clade 3C.2a1 and 41% of B/Victoria lineage viruses belong to a subclade of clade 1A viruses that are antigenically distinct from the current trivalent vaccine component. Click here for more information
The majority of severe cases reported this season are due to influenza type B and have mostly occurred in persons older than 15. Click here for more information
See all weekly influenza updates
Seasonal influenza is a preventable infectious disease with mostly respiratory symptoms. It is caused by influenza virus and is easily transmitted, predominantly via the droplet and contact routes and by indirect spread from respiratory secretions on hands etc.Read more
Surveillance reports and disease data on seasonal influenza
Latest surveillance reports and disease data on seasonal influenza; Flu News Europe, Influenza virus characterisation reports, ECDC Surveillance Atlas, Annual Epidemiological Reports.Read more