A subset of Member States and areas monitors severe disease related to influenza virus infection by surveillance of 1) hospitalized laboratory-confirmed influenza cases in ICUs (12 Member States or areas), or other wards (8 Member States or areas), or 2) severe acute respiratory infections (SARI; 17 Member States or areas).
1.1) Hospitalized laboratory-confirmed influenza cases – ICUs
Among laboratory-confirmed influenza cases reported in ICUs in week 1/2019 (n=252), influenza type A viruses (n=250, 99.2%) were detected more frequently than influenza type B viruses (n=2, 0.8%).
Since week 40/2018, more influenza type A (n=889, 97.3%) than type B (n=25, 2.7%) viruses were detected. Of 366 subtyped influenza A viruses, 318 (86.9%) were A(H1N1)pdm09 and 48 (13.1%) A(H3N2). No influenza B viruses were ascribed to a lineage. Of 248 cases with known age, 45.2% were 15–64 years old and 44.8% were 65 years and older.
1.2) Hospitalized laboratory-confirmed influenza cases – other wards
Laboratory-confirmed influenza cases reported in wards other than ICUs in week 1/2019 (n=156) were all infected with influenza type A viruses.
Since week 40/2018, more influenza type A (n=885, 97.7%) than type B (n=21, 2.3%) viruses were detected. Of 171 subtyped influenza A viruses, 122 (71.3%) were A(H1N1)pdm09 and 49 (28.7%) A(H3N2). No influenza B viruses were ascribed to a lineage. Of 906 cases with known age, 43.6% were 15–64 years old and 33.7% were 65 years and older.
2. SARI surveillance
For week 1/2019, 960 SARI cases were reported by 11 Member States or areas. Of 118 specimens tested for influenza viruses, 17 (14.4%) were positive and all were type A.
Of 13 908 SARI cases reported since week 40/2018, 13 897 had a recorded age and, of these, 66.4% were 0–4 years old, 17.9% were 15–64 years old and 15.7% were 65 years and older. For SARI cases testing positive for influenza viruses since week 40/2018 (n=394), type A viruses have been the most common (99.7%). Of the 386 influenza type A infected cases for which subtyping was performed, 290 (75.1%) were infected by A(H1N1)pdm09 viruses and 96 (24.9%) were infected by A(H3N2) viruses. The influenza B virus was ascribed to the B/Victoria lineage.
For week 1/2019, the EuroMOMO project received data from 21 Member States or areas that were included in pooled analyses. The pooled estimates of all-cause mortality showed expected levels for this time of year in the participating countries.