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; countries and areas mostly located in the eastern part of the Region).



Laboratory-confirmed hospitalized cases

1.1) Hospitalized laboratory-confirmed influenza cases – ICUs  


For week 47/2021, 1 laboratory-confirmed influenza case was reported from an ICU ward (in Sweden). The patient was infected with an influenza type A virus, but subtype was not determined. 

Since week 40/2021, more influenza type A (n=14, 93%) than type B (n=1, 7%) viruses were detected. Of 4 subtyped influenza A viruses, 2 were A(H1)pdm09 and 2 A(H3). No influenza B viruses were ascribed to a lineage. Of 10 cases with known age, 4 were 65 years and older, 2 were 0-4 years old, 1 was 5-14 years old and 1 was 15-64 years old. 


1.2) Hospitalized laboratory-confirmed influenza cases – other wards


For week 47/2021, there were no reports of hospitalized laboratory-confirmed influenza cases in other wards. 
Since week 40/2021, there has been 1 influenza type A virus detected which was not ascribed to a subtype. The patient was in the 0-4 years old range.

Hospital unit