Week 20/2018 (14 - 20 May 2018)

  • Influenza activity has returned to inter-season levels in most countries in the Region.
  • 3% of the individuals sampled from primary health care settings tested positive for influenza viruses (compared to 10% in the previous week).

2017/18 season overview 

  • Aggregated regional data indicated that influenza viruses circulated at high levels 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. Click here for more information
  • Different patterns of dominant influenza virus types 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 45% of B/Victoria lineage viruses fell in 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 were due to influenza type B virus infection and have mostly occurred in persons older than 15 years. Click here for more information
  • Mortality from all causes now appears to have returned to normal expected levels in all 24 participating countries and regions that report to EuroMOMO. Click here for more information
  • Interim results from 5 European studies indicate 25% to 52% vaccine effectiveness against any influenza. Click here for more information

 

Influenza intensity, spread and dominant virus type/subtype