The Impact of Influenza on US Working-Age Adults: Exploring the Benefits of the Recombinant Influenza Vaccine

Background Despite universal influenza vaccine recommendation in the US, vaccination coverage rates (VCR) in working-age adults (18–64 years) remain suboptimal. Studies have suggested that recombinant influenza vaccines (RIV) offer better protection than standard-dose inactivated influenza vaccines (SD-IIV) in those ages. We explored the potential added benefit of recommending RIV for the US working-age population. Methods We gathered data on influenza burden, vaccine effectiveness, and VCR from the US-CDC (2012–2023, excluding 2020–2021). We conducted a retrospective analysis of the past 10 years to illustrate the influenza burden among adults 18–64 years. We performed an age-stratified analysis using prevalence of chronic conditions to assess their impact on influenza hospitalizations and deaths, and estimated reductions in hospitalizations if RIV had been used instead of SD-IIV during the study period, using an age and risk-group decision-tree model. Results Over the last decade, influenza caused a median of 151,021 hospitalizations (95% CI 139,750–164,130) per season among US working-age adults. Adults aged 50–64 years had 3- to 5-fold higher rates of hospitalization and death than those aged 18–49 years. The 14% of 18–49-year-olds with chronic conditions accounted for more than 28% of hospitalizations and deaths in this group. If RIV had been used instead of SD-IIV, an additional 10,000 hospitalizations could have been prevented each season in these populations. Conclusions Influenza significantly impacts US working-age adults, particularly 50-64-year-olds. Increases in longevity and chronic conditions prevalence are expected, making tailored public health vaccine recommendations important to support healthy aging.