RSV Prefusion F Vaccine for Prevention of Hospitalization in Older Adults

BACKGROUND: Respiratory syncytial virus (RSV) can cause serious illness in older adults. The bivalent RSV prefusion F protein-based vaccine (RSVpreF) has been shown to prevent RSV-associated respiratory illness, but data from randomized trials with regard to its effect on outcomes involving hospitalization are limited.

METHODS: In this pragmatic, open-label trial with individual randomization, participants who were 60 years of age or older were assigned in a 1:1 ratio to receive the RSVpreF vaccine (the RSVpreF group) or no vaccine (the control group) during the 2024-2025 winter season. Baseline and outcome data were collected with the use of national registries. The primary end point was hospitalization for RSV-related respiratory tract disease. Secondary end points included hospitalization for RSV-related lower respiratory tract disease and hospitalization for respiratory tract disease from any cause. The prespecified criterion for success for the primary end point and RSV-related secondary end points was a minimum vaccine effectiveness of greater than 20%.

RESULTS: Of 131,379 participants who underwent randomization, 131,276 were included in the intention-to-treat population. During follow-up, hospitalization for RSV-related respiratory tract disease occurred in 3 of 65,642 participants in the RSVpreF group and in 18 of 65,634 participants in the control group (0.11 events vs. 0.66 events per 1000 participant-years; vaccine effectiveness, 83.3%; 95% confidence interval [CI], 42.9 to 96.9; P = 0.007 for minimum effectiveness of >20%). The RSVpreF group also had fewer hospitalizations for RSV-related lower respiratory tract disease than the control group (1 vs. 12; vaccine effectiveness, 91.7%; 95% CI, 43.7 to 99.8; P = 0.009 for minimum effectiveness of >20%), as well as fewer hospitalizations for respiratory tract disease from any cause (284 vs. 335; vaccine effectiveness, 15.2%; 95% CI, 0.5 to 27.9; P = 0.04 for vaccine effectiveness of >0%). The incidence of serious adverse events was similar in the two groups.

CONCLUSIONS: Among adults 60 years of age or older, the RSVpreF vaccine reduced the incidence of hospitalization for RSV-related respiratory tract disease as compared with no vaccine. (Funded by Pfizer; European Union Clinical Trials number, 2024-516600-42-00; DAN-RSV ClinicalTrials.gov number, NCT06684743.).