Respiratory syncytial virus vaccine effectiveness among US veterans, September, 2023 to March, 2024: a target trial emulation study.
Summary
In a large target trial emulation of 293,704 veterans (146,852 vaccinated), the RSV vaccine showed 78.1% effectiveness against RSV infection, and ~79–80% effectiveness against RSV-related ED/urgent encounters and hospitalizations over a median 124 days. Findings strongly support vaccination of adults ≥60 years.
Key Findings
- Vaccine effectiveness against RSV infection was 78.1% (95% CI 72.6–83.5).
- Effectiveness against RSV-related ED/urgent encounters was 78.7% and against hospitalization was 80.3%.
- Median follow-up was 124 days; large matched cohort (146,852 vaccinated vs weighted controls) supports robust real-world inference.
Clinical Implications
Support routine RSV vaccination in adults ≥60 years, highlighting prevention of infection and reductions in urgent care and hospitalization; strengthens health system planning for seasonal RSV.
Why It Matters
Timely, high-quality real-world effectiveness data for newly approved RSV vaccines in older adults quantifies protection across clinically meaningful outcomes. Directly informs policy, uptake, and risk–benefit communication.
Limitations
- Observational design may be subject to residual confounding despite matching
- Veteran population (predominantly older males) may limit generalizability to other groups
Future Directions
Assess durability across subsequent seasons, variant dynamics, and subgroup effectiveness (e.g., frailty, comorbidities), and optimize vaccination timing and coadministration strategies.
Study Information
- Study Type
- Cohort
- Research Domain
- Prevention
- Evidence Level
- II - Well-designed observational cohort with target trial emulation
- Study Design
- OTHER