Weekly influenza update, week 14, April 2018

Data Graph Map
Period: 02 Apr 2018 - 08 Apr 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.

Flu infographic week 14/2018


Flu infographic week 14/2018 - EN - [PNG-104.74 KB]


  • Influenza viruses continued to circulate in the Region with 28% 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 positivity rates among sentinel specimens, 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.

  • Different patterns of dominant type and A subtypes were observed between the countries of the Region. Influenza A viruses are now 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, more A(H3N2) viruses than A(H1N1)pdm09 viruses were reported.

  • While low in number, 55% of characterized A(H3N2) viruses belong to clade 3C.2a 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. 

  • The majority of severe cases reported this season are due to influenza type B and have mostly occurred in persons above the age of 15 years. 

  • Mortality from all causes based on pooled data from 19 EU countries and regions that reported to EuroMOMO remained elevated in some countries. 

  • Interim results from 5 European studies indicate 25 to 52% vaccine effectiveness against any influenza.