Study Design
Test-negative case-control study
Population
Adults aged 60 years and older enrolled in US integrated health systems with at least 12 months of continuous enrollment prior to the study period. Excludes immunocompromised individuals and those with prior RSV vaccination.
Intervention
Single-dose RSVPreF (Abrysvo, Pfizer) bivalent prefusion F protein vaccine administered during the 2025 pre-season vaccination campaign (August-October 2025).
Comparator
Age- and comorbidity-matched unvaccinated adults from the same health systems during the same respiratory season.
Outcomes
Primary: Vaccine effectiveness against medically-attended RSV-associated LRTD confirmed by RT-PCR. Secondary: VE against RSV-related hospitalization, ICU admission, and all-cause respiratory hospitalization. Safety: Serious adverse events within 42 days post-vaccination.
Want to edit this protocol?
Sign up for free to unlock all features.
Efficacy and Safety of RSVPreF Vaccine in Older Adults: Phase 3 RENOIR Trial Results
Walsh EE, Perez Marc G, Zareba AM, et al. — New England Journal of Medicine (2023)
Real-World Effectiveness of RSV Vaccination Among Medicare Beneficiaries, 2023-2024
Surie D, Bonnell L, Adams K, et al. — MMWR Morbidity and Mortality Weekly Report (2024)
ACIP Recommendations for RSV Vaccination in Adults Aged 60 Years and Older
Melgar M, Britton A, Roper LE, et al. — CDC Advisory Committee on Immunization Practices (2024)
Burden of RSV-Associated Hospitalizations Among US Adults, 2019-2023
Havers FP, Whitaker M, Melgar M, et al. — Clinical Infectious Diseases (2024)
Study team discussion: Data source selection and feasibility notes
Study team — Internal (2025)