A subset of Member States and areas monitor severe disease related to influenza virus infection by surveillance of 1) hospitalized laboratory-confirmed influenza cases in ICUs (11 Member States and areas) or other wards (7 Member States and areas), or 2) severe acute respiratory infection (SARI; 17 Member States and areas, mostly located in the eastern part of the Region).
1.1) Hospitalized laboratory-confirmed influenza cases – ICUs
There was 1 report of hospitalized laboratory-confirmed influenza in an ICU during week 20/2020. It was a type B virus.
Since week 40/2019, more influenza type A (n=3 592, 90%) than type B (n=395, 10%) viruses were detected. Of 1 250 subtyped influenza A viruses, 58% were A(H1N1)pdm09 and 42% A(H3N2). No influenza B viruses were ascribed to a lineage. The majority of cases were reported from three countries: the United Kingdom, France and Spain. Of 2 182 cases with known age, 49% were 15-64 years old and 37% were 65 years and older.
1.2) Hospitalized laboratory-confirmed influenza cases – other wards
There were no reports of laboratory-confirmed influenza in wards other than ICUs for week 20/2020.
Since week 40/2019, more influenza type A (n=6 083, 84%) than type B (n=1 151, 16%) viruses were detected. Of 1 709 subtyped influenza A viruses, 59% were A(H1N1)pdm09 and 41% A(H3N2). No influenza B viruses were ascribed to a lineage. The majority of cases were reported by Ireland and Spain. Of 7 232 cases with known age, 42% were 65 years and older and 31% were 15-64 years old.
2. SARI surveillance
For week 20/2020, 621 SARI cases were reported by 7 Member States or areas. Of 24 specimens tested for influenza viruses, 1 was positive for influenza type B virus.
Of the SARI cases tested for influenza viruses since week 40/2019, those testing positive (n=2 917) were mostly infected by type A viruses (56%). Of the 1 376 influenza type A virus infected cases for which subtyping was performed, 61% were A(H1N1)pdm09 and 39% were A(H3N2) viruses. Of the 682 influenza type B viruses ascribed to a lineage, 99% were B/Victoria.
Of 38 591 SARI cases reported since week 40/2019, 38 235 had a recorded age and, of these, 49% were 0–4 years old and 30% were 15–64 years old.
For week 20/2020, pooled estimates of all-cause mortality from 24 participating countries or regions in the EuroMOMO network show declining levels of excess mortality, after a high excess observed overall for the European countries, which has coincided with the COVID-19 pandemic. This excess mortality has been driven by a very substantial mortality excess in some countries, while other countries have seen no excess. The mortality excess has mainly been seen in the age group of ≥65 years, but also in the age group of 15-64 years.
Mortality now appears to be approaching normal expected levels in several of the affected countries. However, the data reported for the most recent weeks must be read with caution, despite the applied correction for delay in registration.