New RSV Vaccines Prove Effective in Older Veterans, VA Reports

An evaluation by the US Department of Veterans Affairs (VA) shows strong real-world effectiveness of newly approved respiratory syncytial virus (RSV) vaccines in preventing RSV-related illness among older adults. The study, conducted within the Veterans Health Administration (VHA), demonstrated that the vaccines offer significant protection against documented infections, hospitalizations, and emergency care due to RSV in individuals aged 60 and above.

Each year, RSV contributes to tens of thousands of hospitalizations and deaths among seniors, similar in scale to seasonal influenza. Amid this increasing RSV-related morbidity in older populations, the US Food and Drug Administration (FDA) recently approved RSV vaccines RSVPreF3 and RSVpreF for use in adults over 60. The VHA, leveraging its robust electronic health record (EHR) infrastructure and past success in vaccine effectiveness research, emulated a target trial to measure how these vaccines perform outside of clinical trials.

The study analyzed data from September 1 to December 31, 2023, matching 146 852 vaccinated veterans with 582 936 unvaccinated peers. Outcomes were tracked through March 31, 2024. Participants were well-matched demographically, with a median age of 75.9 years. Notably, 94% were male, reflecting the veteran population.

During a median follow-up of 124 days, the incidence of RSV infection among vaccinated individuals was substantially lower than among the unvaccinated. Specifically, the infection rate was 1.7 events per 1000 person-years for vaccinated veterans compared to 7.3 per 1000 person-years for their unvaccinated counterparts. This translates to a vaccine effectiveness (VE) of 78.1% (95% CI, 72.6% to 83.5%).

Moreover, the vaccine’s protective benefits extended to more severe outcomes. VE against RSV-associated emergency department or urgent care visits reached 78.7% (CI, 72.2% to 84.8%), while protection against hospitalization stood at 80.3% (CI, 65.8% to 90.1%).

This data is an important validation of current Centers for Disease Control and Prevention recommendations, which advise that adults aged 60 years and older discuss RSV vaccination with their health care providers. The high effectiveness observed may also inform future strategies to expand vaccine access and encourage uptake in high-risk groups.

With respiratory virus season on the horizon, these results underscore the critical role of vaccination in mitigating the burden of RSV.

Reference

Bajema KL, Yan L, Li Y, et al. Respiratory syncytial virus vaccine effectiveness among US veterans, September, 2023 to March, 2024: a target trial emulation study. Lancet Infect Dis. 2025;25(6):625-633. doi:10.1016/S1473-3099(24)00796-5