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 (n=321) reported in ICUs in week 2/2019, influenza type A viruses (n=319, 99.4%) were detected more frequently than influenza type B viruses (n=2, 0.6%).
Since week 40/2018, more influenza type A (n=1 338, 98.0%) than type B (n=27, 2.0%) viruses were detected. Of 531 subtyped influenza A viruses, 448 (84.4%) were A(H1N1)pdm09 and 83 (15.6%) were A(H3N2). No influenza B viruses were ascribed to a lineage. Of 433 cases with known age, 48.0% were 15–64 years old and 42.7% were 65 years and older.
1.2) Hospitalized laboratory-confirmed influenza cases – other wards
Laboratory-confirmed influenza cases reported in wards other than ICUs (n=172) in week 2/2019 were all infected with influenza type A viruses.
Since week 40/2018, more influenza type A (n=1 309, 98.1%) than type B (n=25, 1.9%) viruses were detected. Of 314 subtyped influenza A viruses, 226 (72.0%) were A(H1N1)pdm09 and 88 (28.0%) were A(H3N2). No influenza B viruses were ascribed to a lineage. Of 1 334 cases with known age, 41.0% were 15–64 years old and 35.7% were 65 years and older.
2. SARI surveillance
For week 2/2019, 848 SARI cases were reported by 13 Member States or areas. Of 423 specimens tested for influenza viruses, 133 (31.4%) were positive and all were type A.
Of 15 577 SARI cases reported since week 40/2018, 15 564 had a recorded age and, of these, 65.5% were 0–4 years old, 18.5% were 15–64 years old and 16.0% were 65 years and older. For SARI cases testing positive for influenza viruses since week 40/2018 (n=596), type A viruses were the most common (99.8%). Of the 587 influenza type A infected cases for which subtyping was performed, 486 (82.8%) were infected by A(H1N1)pdm09 viruses and 101 (17.2%) by A(H3N2) viruses. The 1 influenza type B virus was not ascribed to a lineage.
For week 2/2019, the EuroMOMO project received data from 23 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. However, a few countries were starting to observe some excess mortality in elderly populations.