BACKGROUND: Influenza is a relatively serious infection that causes considerable morbidity and mortality. Epidemics of influenza are reported almost every year. METHODS: Based on the Czech national all-cause mortality and acute respiratory infection/influenza-like illness surveillance data for the 1999/2000 to 2019/2020 influenza seasons, excess deaths attributable to influenza were estimated using the threshold derived as 90th percentile of death counts during nonepidemic periods. Daily death counts broken by the 5-year age intervals were modelled via Poisson generalised additive model. RESULTS: The estimated total number of excess deaths from influenza during study period was 22,306. Thus, the mean total of excess deaths related to influenza per season was 1062 for the age group 40-94 years. The total number of excess deaths increased steadily with age from the 40-44 age group to the 85-89 age group, which accounted for the highest percentage of excess deaths (17%), followed closely by the 80-84 age group (16%). The age groups 40-44 years and 45-49 years contributed the least (3% each). More than three quarters of excess deaths occurred at age 65 and over (17,027 cases; 76%). Relative numbers of excess deaths per 100,000 population peaked in the oldest age groups of 85-89 and 90-94 years. CONCLUSIONS: We estimate that at least 0.98% of all-cause mortality throughout the study period was attributable to influenza in the Czech Republic. This excess is not negligible, and public health actions in the field of influenza prevention are vitally needed.

Department of Biostatistics National Institute of Public Health Prague Czech Republic

Department of Epidemiology and Biostatistics 3rd Faculty of Medicine Charles University Prague Czech Republic

Department of Infectious Diseases Epidemiology National Institute of Public Health Prague Czech Republic

Faculty of Environmental Sciences Czech University of Life Sciences Prague Czech Republic

Institute of Atmospheric Physics Czech Academy of Sciences Prague Czech Republic

Institute of Computer Science Czech Academy of Sciences Prague Czech Republic

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