Weekly influenza update, week 45, November 2017

Period: 06 Nov 2017 - 12 Nov 2017

ECDC and WHO/Europe publish weekly influenza surveillance data in the report Flu News Europe.


  • Influenza activity across Europe remained at a low level.
  • Overall, 4.5% of individuals sampled, on presenting with ILI or ARI to sentinel primary healthcare sites, tested positive for influenza viruses, which is a slight increase compared to the previous week (1%).
  • Data from 19 countries or regions reporting to the EuroMOMO project indicated that all-cause mortality was at low levels, as expected for this time of the year.

2017/18 season overview 

  • Since week 40/2017, few influenza viruses have been detected in sentinel and non-sentinel specimens.
  • For detections from both sentinel and non-sentinel surveillance systems, most viruses subtyped or assigned to a lineage this season were identified as A(H3N2) and B/Yamagata viruses, respectively.
  • While low in number (n=21), over 80% of the A(H3N2) viruses genetically characterized belong to clade 3C.2a, the vaccine virus clade, as described in the WHO recommendations for vaccine composition for the northern hemisphere 2017–18.