A subset of countries and areas monitor severe disease related to influenza virus infection by surveillance of
1) hospitalized laboratory-confirmed influenza cases in ICUs or other wards, or
2) severe acute respiratory infections (SARI).
For week 3/2023, 3 379 SARI cases were reported by 17 countries or areas (Albania, Belarus, Belgium, Bosnia and Herzegovina, Germany, Ireland, Kyrgyzstan, Lithuania, Malta, Republic of Moldova, Romania, Russian Federation, Serbia, Slovakia, Spain, Ukraine and Uzbekistan). Of 1 037 specimens tested for influenza viruses, 15% (n=160) were positive. Of these, influenza type A viruses (n=126, 79%) were detected more frequently than influenza type B viruses (n=34, 21%). Of 97 subtyped A viruses, 78% were A(H1)pdm09 and 22% A(H3). No type B viruses were ascribed to a lineage. Of 11 countries and areas across the Region that each tested at least 10 SARI cases, 9 reported positivity rates above 10%: Romania (49%), Serbia (42%), Lithuania (36%), Russian Federation (31%), Ireland (27%), Ukraine (26%), Albania (25%), Kyrgyzstan (25%) and Bosnia and Herzegovina (23%).
For the season, 87 474 SARI cases were reported by 26 countries or areas (Albania, Armenia, Belarus, Belgium, Bosnia and Herzegovina, Croatia, Georgia, Germany, Ireland, Kazakhstan, Kyrgyzstan, Lithuania, Malta, Montenegro, North Macedonia, Republic of Moldova, Romania, Russian Federation, Serbia, Slovakia, Spain, Tajikistan, Türkiye, Ukraine, Uzbekistan and Kosovo* (in accordance with Security Council resolution 1244 (1999))).
For SARI cases testing positive for influenza virus since week 40/2022, type A viruses have been the most common (n=2 254, 77%) and of these 1 927 were subtyped: 1 434 (74%) were infected by A(H1)pdm09 viruses and 493 (26%) were infected by A(H3) viruses. Only 23% (n=167) of the influenza B viruses were ascribed to a lineage, all were B/Victoria.
* 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.