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 infection (SARI; 17 Member States or areas).

1.1) Hospitalized laboratory-confirmed influenza cases – ICUs

Influenza type A viruses were detected in all of the laboratory-confirmed influenza cases reported in ICUs for week 15/2019 (n=46).

Since week 40/2018, more influenza type A (n=7 037, 99%) than type B (n=56, 1%) viruses were detected. Of 3 095 subtyped influenza A viruses, 67% were A(H1N1)pdm09 and 33% were A(H3N2). No influenza B viruses were ascribed to a lineage. Of 3 943 cases with known age, 47% were 65 years and older and 44% were 15-64 years old.

1.2) Hospitalized laboratory-confirmed influenza cases – other wards

Among laboratory-confirmed influenza cases reported in wards other than ICUs in week 15/2019 (n=43), all were influenza type A viruses.

Since week 40/2018, more influenza type A (n=9 377, 99%) than type B (n=66, 1%) viruses were detected. Of 3 652 subtyped influenza A viruses, 56% were A(H1N1)pdm09 and 44% were A(H3N2). Of 2 influenza B viruses ascribed to a lineage, 1 was B/Yamagata and 1 was B/Victoria. Of 9 443 cases with known age, 46% were 65 years and older and 32% were 15-64 years old.

2. SARI surveillance

For week 15/2019, 1 054 SARI cases were reported by 11 countries or areas. Of these cases, 127 specimens were tested for influenza viruses with 20 (16%) of them being positive. Of these, influenza type A viruses (n=19: 95%) were detected more frequently than influenza type B viruses (n=1: 5%).

Of 37 966 SARI cases reported since week 40/2018, 37 910 had a recorded age and, of these, 57% were 0-4 years old and 24% were 15-64 years old. For SARI cases testing positive for influenza virus since week 40/2018 (n=2 799), type A viruses have been the most common (99%). Of the 2 511 influenza type A infected cases for which subtyping was performed, 79% were infected by A(H1N1)pdm09 viruses and 21% were infected by A(H3N2) viruses. 1 type B virus ascribed to a lineage was B/Yamagata.

Mortality monitoring

For week 15/2019, the EuroMOMO project received data from 23 countries or areas that were included in pooled analyses. The pooled estimates indicated that the all-cause excess mortality observed in previous weeks has returned to normal levels.