Severity

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 11/2019 (n=99), all were influenza type A viruses.

Since week 40/2018 substantially more influenza type A (n=6 569, 99.2%) than type B viruses (n=54, 0.8%) were detected. Of 2 691 subtyped influenza A viruses, 71.3% were A(H1N1)pdm09 and 28.7% were A(H3N2). No influenza type B viruses were ascribed to a lineage. Of 3 624 cases with known age, 45.0% were 15–64 years old and 46.6% were 65 years and older.

1.2) Hospitalized laboratory-confirmed influenza cases – other wards

Among laboratory-confirmed influenza cases reported in wards other than ICUs in week 11/2019 (n=92), influenza type A viruses (98.9%) were detected more frequently than influenza type B viruses (1.1%).

Since week 40/2018, substantially more influenza type A (n=8 557, 99.3%) than type B viruses (n=57, 0.7%) were detected. Of 3 166 subtyped influenza A viruses, 60.5% were A(H1N1)pdm09 and 39.5% were A(H3N2). The 1 influenza type B virus ascribed to a lineage was B/Yamagata. Of 8 614 cases with known age, 45.1% were 65 years and older and 33.4% were 15–64 years old.

2. SARI surveillance

For week 11/2019, 1 304 SARI cases were reported by 13 Member States or areas. Of 228 specimens tested for influenza viruses, 30.7% were positive. Of these, influenza type A viruses (98.6%) were detected much more frequently than influenza type B viruses (1.4%).

Of 33 023 SARI cases reported since week 40/2018, 32 967 had a recorded age and, of these, 57.6% were 0–4 years old and 23.9% were 15–64 years old. For SARI cases testing positive for influenza virus since week 40/2018 (n=2 627), almost all were type A viruses (99.5%). Of the 2 365 influenza type A virus-infected cases for which subtyping was performed, 80.4% were infected by A(H1N1)pdm09 viruses and 19.6% by A(H3N2) viruses. The 1 influenza type B virus ascribed to a lineage was B/Yamagata.

Mortality monitoring

For week 11/2019, the EuroMOMO project received data from 24 countries or areas that were included in pooled analyses. The pooled estimates indicated that the excess mortality among persons aged 15–64 years and 65 years and older observed in recent weeks continued to decline.