Large Medicare Study Supports RSV Vaccine Effectiveness in Seniors
A large U.S. study has found that vaccines against respiratory syncytial virus, or RSV, substantially reduced hospitalizations and deaths among adults aged 65 and older. Published September 18 in JAMA Network Open, the analysis covered 14.8 million Medicare beneficiaries and found that vaccination lowered the risk of an RSV-related hospitalization or death by about 80 percent.
The findings address earlier uncertainty about whether results from clinical trials would hold up under real-world conditions. Later trial phases occurred during the COVID-19 pandemic, when RSV circulated at unusually low levels. This led some researchers to question whether the vaccines would perform as strongly once RSV activity returned to more typical patterns.
The two vaccines evaluated, made by GlaxoSmithKline and Pfizer, produced similar results. Dr. Edward Walsh, a University of Rochester professor who was not involved in the study, said the findings closely matched earlier efficacy trials and smaller effectiveness studies. He noted that the Medicare population provided a considerably broader evidence base than previous research.
Researchers also examined whether differences in health care access influenced the results. Vaccinated participants were more likely to live in affluent areas and to have received flu and COVID-19 vaccines. After statistical analyses designed to account for those factors, the estimated protection from RSV vaccination remained essentially unchanged.
Questions remain about booster doses. Researchers are studying whether another injection two or three years after the first would restore immunity. Available evidence suggests a second dose may not produce as strong an antibody response, but the clinical significance is not yet clear. No routine booster recommendation has been established based on these findings. Meanwhile, scientists continue developing vaccines against other respiratory viruses and exploring broader approaches that could protect against multiple infections by stimulating shared or nonspecific immune defenses.