Hospital Surveillance

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 infection (SARI).


Severe acute respiratory infection (SARI)-based hospital surveillance


For week 18/2022, 1 746 SARI cases were reported by 13 countries or areas (Albania, Belarus, Georgia, Germany, Ireland, Lithuania, Malta, Montenegro, Romania, Russian Federation, Serbia, Spain and Ukraine). Of 290 specimens tested for influenza viruses, 7% (n=21) were positive. Of these, influenza type A viruses (n=19, 90%) were detected more frequently than influenza type B viruses (n=2). Of 16 subtyped influenza type A viruses, 15 were A(H3) and 1 was A(H1)pdm09. The highest positivity rate (18%) for influenza virus detections was reported by Georgia.


For the season, 128 099 SARI cases were reported by 23 countries or areas (Albania, Armenia, Belarus, Belgium, Croatia, Georgia, Germany, Ireland, Kazakhstan, Kyrgyzstan, Lithuania, Malta, Montenegro, North Macedonia, Republic of Moldova, Romania, Russian Federation, Serbia, Spain, Turkey, Ukraine, Uzbekistan and Kosovo (in accordance with Security Council resolution 1244 (1999))). For SARI cases testing positive for influenza virus since week 40/2021, type A viruses have been the most common (n=1 279, 95%). For 1 137 cases where influenza virus subtyping was performed, 1116 (98%) were infected by A(H3) viruses and 21 (2%) were infected by A(H1)pdm09 viruses. Of those influenza B viruses that have been ascribed to a lineage (n=10, 5%), 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.