ECDC publish seasonal influenza annual epidemiological report for 2019-2020

On 6 August 2020, the European Centre for Disease Prevention and Control (ECDC) published its seasonal influenza annual epidemiological report for 2019-2020. Influenza activity started in week 45 of 2019, and returned to baseline levels in week 13 of 2020, earlier than previous seasons.

In key findings from the report: 

• Similar proportions of influenza A(H1)pdm09, A(H3) and B/Victoria were detected throughout the season. B/Victoria lineage viruses have greatly outnumbered those of the B/Yamagata lineage. 
• Different patterns of dominant type and A subtypes were observed among the countries. Early on, circulation of A(H3) was higher and later in the season increased proportions of A(H1)pdmp9 and B/Victoria viruses were observed. 
• The majority of severe cases reported this season were due to influenza virus type A infection and these mostly occurred in persons older than 40 years of age. 
• The majority of deceased hospitalised influenza patients were at least 65 years old and had influenza A virus infection. 
• During the period of high influenza virus circulation in early January and February, a slight excess mortality from all causes was observed, possibly related to influenza, while later in the season the excess mortality was driven by COVID-19. 
• The vast majority of influenza viruses tested were susceptible to neuraminidase inhibitors. 
• A moderately good vaccine effectiveness was observed, which was higher for type B and A(H1)pdm09 viruses.

Source: ECDC, 6 August 2020