Weekly influenza update, week 19, May 2018

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Period: 07 May 2018 - 13 May 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 19/2018


Flu infographic week 19/2018 - EN - [PNG-105.61 KB]


  • Influenza activity had returned to inter-season levels in most of the countries in the Region.
  • 10% of the individuals sampled from primary healthcare settings tested positive for influenza viruses (compared to 6% in the previous week).

2017/18 season overview 

  • Influenza viruses circulated at high levels in the Region between weeks 52/2017 and 12/2018 (based on increased proportions - 40% and above - of sentinel specimens testing positive for influenza viruses). This is longer than in recent seasons and may have contributed to the severity of this season.
  • 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.
  • While low in numbers, characterized A(H3N2) viruses fell mainly in clade 3C.2a (57%) and subclade 3C.2a1 (42%), while 43% of B/Victoria lineage viruses fell in a subclade of clade 1A viruses that are antigenically distinct from the current trivalent vaccine component.
  • The majority of severe cases reported this season were due to influenza virus type B infection and have mostly occurred in persons older than 15 years.
  • Mortality from all causes now appears be have returned to normal expected levels in all 20 participating countries and regions that report to EuroMOMO.
  • Interim results from 5 European studies indicate 25 to 52% vaccine effectiveness against any influenza.

See all weekly influenza updates


Weekly influenza update, week 2, January 2019

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Weekly influenza update, week 1, January 2019

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Weekly influenza update, week 20, May 2018

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Weekly influenza update, week 18, April/May 2018

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Weekly influenza update, week 17, April 2018

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