Weekly influenza overview

Week 14/2021 (05 April–11 April 2021)


  • Influenza activity remained at interseasonal levels.


  • Of the 948 specimens tested for influenza viruses in week 14/2021, from patients presenting with ILI or ARI symptoms to sentinel primary healthcare sites, two were positive for influenza type A viruses.


  • Influenza viruses were detected sporadically from non-sentinel sources (such as hospitals, schools, primary care facilities not involved in sentinel surveillance, or nursing homes and other institutions). Both influenza type A and type B viruses were detected.


  • There was 1 hospitalized laboratory-confirmed influenza case from a non-ICU ward reported in week 14/2021.


Qualitative indicators


  • Of 39 countries and areas reporting on intensity of activity, 33 reported baseline and 6 (Azerbaijan, Estonia, Kosovo (in accordance with UN Security Council resolution 1244 (1999)), Slovakia, Slovenia, Ukraine) reported low intensity for week 14/2021.


  • Of 40 countries and areas that reported on geographic spread, 34 reported no activity and 6 (Azerbaijan, Portugal, Slovakia, Ukraine, United Kingdom (England), United Kingdom (Scotland)) reported sporadic spread for week 14/2021.




Please note: 

  1. 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, including SARS-CoV-2, leading to observed increases in the absence of influenza virus detections
  2. 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. 
© World Health Organization 2020
© European Centre for Disease Prevention and Control 2020
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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.