Week 27–29/2017 (3 – 23 July 2017)    

  • Influenza activity was at out-of-season levels in all countries. All reporting countries continued to report low intensity of influenza activity.
  • Influenza viruses were detected sporadically both in sentinel and non-sentinel specimens, with only influenza type A viruses detected
  • For week 29/2017, data from the 19 countries or regions reporting to the EuroMOMO project indicated a transient increase in mortality in some countries in southern Europe, most likely due to high temperatures.

 

Additional information on global influenza activity is available from WHO’s biweekly global updates.

 

2016/17 season overview

 

  • After an earlier start than usual (week 46/2016), influenza activity peaked between weeks 52/2016 and 4/2017. Between weeks 12 and 20/2017, most countries reported decreased influenza activity with the proportion of sentinel detections returning to the epidemic threshold value (10%) in week 17/2017.
  • A(H3N2) viruses predominated by a large margin during the season.
  • Significant mortality from all causes was observed in people aged 15–64 years, and markedly so in people aged 65 years or older, in the majority of the 20 reporting countries or regions. This is commonly seen when the predominant viruses circulating are A(H3N2).
  • Two-thirds of the A(H3N2) viruses genetically characterized belonged to subclade 3C.2a1, but remained antigenically similar to the clade 3C.2a vaccine virus, as described in the WHO recommendations for vaccine composition for the northern hemisphere 2017–18. See also the WHO CC London May 2017 report.

 

Influenza intensity, spread and dominant virus type/subtype