New RSV Vaccine Shows Strong Protection in Veterans

TOPLINE:

A single dose of the recombinant respiratory syncytial virus (RSV) vaccine demonstrates effectiveness against infections and associated hospitalizations in veterans aged 60 years or older during the 2023-2024 respiratory illness season. This protection extends across age groups and immunocompromised individuals.

METHODOLOGY:

• Researchers conducted a target trial emulation study to evaluate the real-world effectiveness of a single dose of recombinant RSV vaccine (RSVPreF3 or RSVpreF) among veterans enrolled in the Veterans Health Administration in the United States between September 1 and December 31, 2023.
• They analyzed 146,852 vaccinated veterans (69.2%, RSVPreF; 29.9%, RSVPreF3) propensity matched with 582,936 unvaccinated ones (median age, ~76 years; ~94% men; immunocompromised individuals, 11.2%) who were followed up for a median of 124 days.
• The primary outcome was any positive RSV test result obtained from day 14 after vaccination.
• The secondary outcomes were RSV-associated emergency department or urgent care visits, hospitalizations, intensive care unit (ICU) admissions, and death.

TAKEAWAY:

• Vaccine effectiveness against documented RSV infections was 78.1% (95% CI, 72.6-83.5), with incidence rates of infections lower in the vaccinated group than in the unvaccinated group (1.7 vs 7.3 per 1000 person-years).
• Likewise, vaccine effectiveness against RSV-associated emergency department or urgent care visits was 78.7% (95% CI, 72.2-84.8), with rates of infections lower in the vaccinated group than in the unvaccinated group (1.3 vs 5.7 per 1000 person-years).
• Immunocompromised veterans demonstrated a lower vaccine effectiveness of 71.6% (95% CI, 55.4-85.2); however, infection rates remained lower in the vaccinated group than in the unvaccinated group (5.8 vs 19.9 per 1000 person-years).
• Hospitalizations, ICU admission rates, and mortality rates were also lower in the vaccinated group than in the unvaccinated group.

IN PRACTICE:

“These results give confidence that an RSV vaccine for older adults is likely to provide protection against RSV infection and RSV disease, at least in the first season following vaccination,” wrote the author of an accompanying comment.

SOURCE:

The study was led by Kristina L. Bajema, MD, Veterans Affairs Portland Health Care System, Portland, Oregon. It was published online on January 20, 2025, in The Lancet Infectious Diseases.

LIMITATIONS:

This study did not account for veterans who sought care outside of the Veterans Health Administration. While the study employed rigorous matching to ensure the similarity of demographic, geographic, and clinical characteristics, there could still have been residual confounding. Also, the study was not designed to estimate the protective effect of the vaccine against mild RSV illness.

DISCLOSURES:

This study was supported by the US Department of Veterans Affairs Cooperative Studies Program and funded in part by the US Department of Health and Human Services Biomedical Advanced Research and Development Authority and US Food and Drug Administration. One of the authors reported receiving consulting support from Van-Breemen & Hynes and having a subcontract at Oregon State University for a Patient-Centered Outcomes Research Institute grant. Others reported no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.