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

Of the laboratory-confirmed influenza cases reported in ICUs for week 20/2019 (n=7), all were influenza type A viruses reported by the United Kingdom.

Since week 40/2018, almost all viruses detected have been influenza type A (n=7 272, 99%). Only 1% were type B (n=63). Of 3 343 subtyped influenza A viruses, 66% were A(H1N1)pdm09 and 34% were A(H3N2). No influenza B viruses were ascribed to a lineage. Of 4 082 cases with known age, 47% were at least 65 years old, 45% were 15-64 years old, and 6% were under 5 years old.

1.2) Hospitalized laboratory-confirmed influenza cases – other wards

Among laboratory-confirmed influenza cases reported in wards other than ICUs for week 20/2019 (n=8), all were influenza type A viruses.

Since week 40/2018, almost all viruses detected have been influenza type A (n=9 890, 99%). Only 1% were type B (n=74). Of 4 068 subtyped influenza A viruses, 54% were A(H1N1)pdm09 and 46% were A(H3N2). Of 2 influenza B viruses ascribed to a lineage, 1 was B/Yamagata and 1 was B/Victoria. Of 9 964 cases with known age, 47% were at least 65 years old, 32% were 15-64 years old, and 15% were under 5 years old.

2. SARI surveillance

For week 20/2019, 313 SARI cases were reported by 11 Member States or areas. Of these cases, 54 specimens were tested for influenza viruses and 1 (1.9%) tested positive for A(H3N2) virus.

Of 42 602 SARI cases reported since week 40/2018, 42 494 had a recorded age and, of these, 58% were 0-4 years old and 23% were 15-64 years old. For SARI cases testing positive for influenza virus since week 40/2018 (n=2 843), type A viruses have been predominating (99%). Of the 2 540 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 20/2019, the EuroMOMO project received data from 23 countries or areas that were included in pooled analyses. The pooled estimates indicated that all-cause mortality was within expected ranges.