A single dose of RSV vaccine may protect older adults across 3 virus seasons, although its effectiveness wanes over time, according to findings from an international trial involving Australian participants.
The study found the vaccine was 82.6% effective in the first RSV season, and that this efficacy dropped to 56% and 48% in seasons 2 and 3, respectively.
Despite the decline in effectiveness, infection rates remained lower among those who received the vaccine compared with the placebo group.
Researchers also examined whether a booster dose could extend protection.
They found that having a booster about a year after the first vaccine made little difference to the efficacy of the vaccine.
The authors say further research is needed to establish the optimal booster strategy.
To read the study, visit: thelancet.com/journals/lanres/article/PIIS2213-2600(25)00048-7/abstract
