• Posted September 3, 2025

One Dose of RSV Vaccine May Shield Older People for Two Seasons

A single dose of RSV vaccine might protect seniors for two cold and flu seasons in a row, a new study says.

Vaccination reduced seniors’ risk of hospitalization by 58% during two RSV seasons, researchers reported Aug. 30 in the Journal of the American Medical Association.

“These results clearly demonstrate that the RSV vaccines prevent hospitalizations and critical illness due to RSV infection among older Americans,” said principal investigator Dr. Wesley Self, senior vice president for clinical research at Vanderbilt University Medical Center in Nashville, Tennessee. “It is exciting to see the public health benefits of this new vaccination program.”

However, the vaccine’s effectiveness waned between the first and second years, raising questions regarding how often seniors should get the jab.

RSV causes substantial illness among seniors 60 and older in the fall and winter, with as many as 150,000 hospitalizations and 8,000 deaths each year, researchers said in background notes.

For the study, researchers tracked the health of nearly 7,000 people 60 and older who were hospitalized for a severe respiratory illness at 26 hospitals in 20 states in either the 2023-2024 or 2024-2025 RSV seasons.

Results revealed 69% protection against RSV-related hospitalization in the first year and 48% in the second year following vaccination, researchers said.

“Our data show that the beneficial effects of RSV vaccines appear to wane over time,” Self said in a news release.

The U.S. Centers for Disease Control and Prevention (CDC) recommends a single dose of RSV vaccine for all adults 75 and older, as well as those between 50 and 74 who are at increased risk for severe RSV infection.

It’s not an annual vaccine, the CDC says.

“People who have already received one dose (including last year) have completed their vaccination and should not receive another dose at this time,” the CDC’s website says.

These results indicate that those guidelines might need review, Self said.

“Redosing the vaccine at some interval after the initial dose could be a strategy to maintain protection over longer periods of time,” Self said. “It will be important to continue to closely monitor vaccine effectiveness over time to understand how long the benefit lasts after a single dose and if repeat dosing should be considered.”

More information

The U.S. Centers for Disease Control and Prevention has more on the RSV vaccine.

SOURCE: Vanderbilt University Medical Center, news release, Aug. 29, 2025