OBJECTIVES: To estimate the economic burden caused by seasonal influenza in subjects aged 50-64 in the USA, from a societal perspective.

METHODS: We analyzed 10 influenza seasons, 2012-13 through 2022-23, excluding 2020-21 because of the disruption caused by the SARS-CoV-2 pandemic. We used 2024 demographic data, CDC’s official and publicly available reports on influenza epidemiology, state-of-the-art published data on healthcare resource utilization and unitary costs. Influenza-related health states under analysis were: Symptomatic illnesses, Medical visits, Hospitalizations, Deaths. We quantified total Direct and Indirect Costs (in 2024 US$), based on published data on healthcare resource utilization and unitary costs.

RESULTS: We estimated the current seasonal influenza burden for subjects aged 50-64, in the USA, at 3.2 million outpatient visits / yr. [2.3, 5.2], 78 thousand hospitalizations / yr. [61, 126], and 4.4 thousand fatal cases / yr. [3.0, 8.2]. Direct medical costs for subjects aged 50-64 were estimated at US$ 3.5 billion / yr. [0.2, 25.3]. The largest contributor was found to be hospitalizations: US$ 2.4 billion / yr. [0.16, 16.7]. Indirect costs due to work absenteeism, for subjects aged 50-64, were estimated at US$ 2.9 billion / yr. [2.2, 4.8], associated with influenza-related symptomatic illness cases, medical visits and hospitalizations. Influenza-related annual fatal cases, in the 50-64 population, were found to represent 69 thousand [48, 129] Years of Life Lost [YLLs], by considering a life expectancy of 79.9 yr. and a discount rate of 3%. The societal impact of seasonal influenza-related mortality in the 50-64 population was estimated at US$ 5.9 billion / yr. [4.1, 11.1], by considering the aforementioned discounted YLLs and a GDP/capita at US$ 85 thousand / yr.

CONCLUSIONS: In the USA, substantial economic and humanistic burden are caused annually by seasonal influenza in adults aged 50-64. Wider and stronger prevention measures are required.