Mortality associated with different influenza subtypes in France between 2015-2019

BackgroundHigh levels of excess mortality during periods of active influenza circulation in France were observed in the years preceding the COVID-19 pandemic. Some of the factors that affect the rates of influenza associated mortality are influenza vaccination coverage levels in different population groups and practices for testing for influenza and related use of antiviral medications for various illness episodes (including pneumonia hospitalizations) during periods of active influenza circulation in the community. MethodsData on sentinel ILI surveillance and sentinel virological surveillance in France were combined in a framework of a previously developed regression model to estimate the number of deaths associated with the circulation of the major influenza subtypes (A/H3N2, A/H1N1, B/Yamagata and B/Victoria) in France between 2015-2019. ResultsBetween week 3, 2015 and week 2, 2020, there were on average 15403 (95% CI (12591,18229)) annual influenza-associated deaths, of which 60.3% (49.9%,71.9%) were associated with influenza A/H3N2, and 29.5% (13.3%,45.5%) were associated with influenza B/Yamagata. During weeks when levels of ILI consultation in mainland France were above 50 per 100,000 persons, 7.9% (6.5%,9.4%) of all deaths in France were influenza-associated. ConclusionsHigh rates of influenza-associated mortality in France prior to the COVID-19 pandemic suggest that boosting influenza vaccination coverage in different population groups and testing for influenza in respiratory illness episodes (including pneumonia hospitalizations) during periods of active influenza (particularly influenza A/H3N2) circulation in combination with the use of antiviral medications is needed to mitigate the impact of influenza epidemics.