Syndromic surveillance data
Of the countries and areas in which thresholds for ILI activity are defined, countries in eastern (n=2; Azerbaijan and Republic of Moldova), northern (n=5; Estonia, Ireland, Latvia, Lithuania and Norway), southern (n=6; Croatia, Greece, Israel, North Macedonia, Romania and Slovenia) and western (n=7; Austria, Belgium, Czechia, Hungary, Luxembourg, Poland and Switzerland) areas of the European Region reported activity above baseline levels.
Of the countries and areas in which thresholds for ARI activity are defined, countries in eastern (n=1; Republic of Moldova), northern (n=1; Latvia), southern (n=4; Albania, Bulgaria, Romania and Slovenia) and western (n=1; Czechia) areas of the European Region reported activity above baseline levels.
Assessment of the syndromic surveillance data of ILI or ARI rates might be driven by respiratory infections with viruses other than influenza, including SARS-CoV-2 and RSV, leading to observed increases in the absence of influenza virus detections. The thresholds mentioned are related to the Moving Epidemic Method (MEM) method and based on historic ILI/ARI data.
Viruses detected in sentinel-source specimens (ILI and ARI)
For week 3/2023, 827 (22%) of 3 777 sentinel specimens tested positive for an influenza virus; 80% were type A and 20% were type B. Of 488 subtyped A viruses, 63% were A(H1)pdm09 and 37% A(H3). All 46 type B viruses ascribed to a lineage were B/Victoria.
Of 34 countries and areas across the Region that each tested at least 10 sentinel specimens in week 3/2023, 28 reported a positivity rate at or above 10% (median 29%; range 10% - 82%), of which 6 reported positivity above 40%: Romania (82%), Netherlands (48%), Belgium (46%), Finland (46%), Slovenia (44%) and Kosovo (in accordance with UN Security Council Resolution 1244 (1999)) (43%).
For the season to date, 14 709 (23%) of 64 517 sentinel specimens tested positive for an influenza virus. More influenza type A (n=13 591, 92%) than type B (n=1 118, 8%) viruses have been detected. Of 10 984 subtyped A viruses, 7 945 (72%) were A(H3) and 3 039 (28%) were A(H1)pdm09. All 355 influenza type B viruses ascribed to a lineage were B/Victoria (68% of type B viruses were reported without a lineage).
Details of the distribution of viruses detected in non-sentinel-source specimens are presented in the virus characteristics section.
External data sources
Influenzanet collects weekly data on symptoms in the general community from different participating countries across the EU/EEA. Please refer to the website for additional information for week 3/2023.
* 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.