Weekly influenza overview

Week 10/2023 (6 March - 12 March 2023)

 

  • The percentage of all sentinel primary care specimens from patients presenting with ILI or ARI symptoms that tested positive for an influenza virus increased from 24% in the previous week to 26% in week 10/2023 which remains above the epidemic threshold (10%).
  • 19 of 40 countries or areas reported medium or high intensity and 20 of 39 countries reported widespread activity indicating substantial seasonal influenza virus circulation across the Region.    
  • Of the 21 countries that reported sentinel primary care specimen influenza virus positivity above the 10% epidemic threshold, France, Hungary, Romania and Slovenia reported activity above 40%.   
  • Influenza type A and type B viruses were detected in sentinel and non-sentinel surveillance, with influenza type B predominating in both systems.  
  • Hospitalized patients with confirmed influenza virus infection were reported from ICU (with higher proportions of type B viruses), other wards (with higher proportions of type A viruses) and SARI surveillance (with higher proportions of type B viruses). Six countries or areas reported influenza virus positivity rates above 10% in SARI surveillance.  

 

Qualitative indicators

For week 10/2023, of 40 countries and areas reporting on intensity of influenza activity, 6 reported baseline-intensity (Iceland, Netherlands, Ukraine, United Kingdom (England, Northern Ireland and Scotland), 15 reported low-intensity (across the Region), 18 reported medium-intensity (across the Region) and 1 reported high-intensity (Croatia).


Of 39 countries and areas reporting on geographic spread of influenza viruses, 1 reported no activity (Georgia), 7 reported sporadic spread (Azerbaijan, Belgium, Bulgaria, Kazakhstan, North Macedonia, United Kingdom (England and Northern Ireland)), 4 reported local spread (Belarus, Lithuania, Malta and Slovakia), 7 reported regional spread (Albania, Austria, Republic of Moldova, Romania, Serbia, United Kingdom (Scotland) and Kosovo (in accordance with UN Security Council Resolution 1244 (1999))) and 20 reported widespread activity (across the Region).

 

Please note: 

  • Assessment of the intensity of activity indicator includes consideration of ILI or ARI rates. These ILI or ARI rates might be driven by respiratory infections other than influenza virus, including SARS-CoV-2, leading to observed increases in the absence of influenza virus detections.

  • Assessment of intensity and geographic spread indicators includes consideration of sentinel and non-sentinel influenza virus detection data. Non-sentinel influenza virus detections, often higher, might translate into reporting of elevated geographic spread even in the absence of sentinel detections and/or low intensity of activity measured by ILI and ARI incidence.

 

* The administrative boundaries include spatial feature for Kosovo, this designation being without prejudice to position on status, and is in line with United Nations Security Council Resolution 1244 (1999) and the International Court of Justice Opinion on the Kosovo Declaration of Independence.

 

© World Health Organization 2023
© European Centre for Disease Prevention and Control 2023
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The designation employed and the presentation of this material do not imply the expression of any opinion whatsoever on the part of the Secretariat of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers and boundaries.
* The administrative boundaries include spatial feature for Kosovo, this designation being without prejudice to position on status, and is in line with United Nations Security Council Resolution 1244 (1999) and the International Court of Justice Opinion on the Kosovo Declaration of Independence.
Administrative boundaries: © EuroGeographics, © UN-FAO.