The protection offered by the respiratory syncytial virus (RSV) vaccine wanes over time for older adults, even with a booster dose 1 year after initial vaccination, according to a study published in Lancet Respiratory Medicine. This clinical trial of nearly 25,000 participants in 17 countries is one of the first studies measuring the efficacy of the relatively new RSV vaccine over subsequent seasons for those aged 60 years or older. Research data shows that efficacy was 82.6% in season 1; 56.1% in season 2; and 48.0% in season 3. The efficacy found for the group who received a single booster dose 1 year after the initial dose was 68.4% in season 3. The RSV vaccines first hit the market in 2023, and dosing schedule recommendations may change as more post-market data becomes available.
Helpful overall: Despite a decrease in efficacy over time, a single vaccine dose was efficacious against RSV-related lower respiratory tract disease over 3 RSV seasons, according to the authors. Across the seasons, the single-dose regimen demonstrated a cumulative efficacy of 62.9% (97·5% confidence interval 46.7–74.8) against RSV-related lower respiratory tract disease.