The RSV vaccine is not a yearly vaccine. It is given as a single dose, and the CDC currently recommends against getting another dose if you’ve already been vaccinated. This sets it apart from the flu shot and updated COVID vaccines, which require new doses each year.
How Long One Dose Lasts
A single RSV vaccine provides protection for at least two years in adults 50 and older. Clinical trial data from Pfizer’s vaccine showed efficacy of about 89% against severe RSV lung disease in the first season, dropping only modestly to about 78% in the second full season. Across both seasons combined, efficacy held at roughly 82%. Protection against milder illness declined a bit more, from about 65% after season one to 56% after season two, but still remained meaningful.
All three approved RSV vaccines for adults (two protein-based vaccines and one mRNA-based vaccine) are administered as a single intramuscular injection. None of them have an approved booster dose at this time.
Who Should Get It
The CDC recommends RSV vaccination for adults 50 and older who haven’t already received a dose. The 2024 updated guidance specifically noted that the recommendation applies to people who did not get an RSV vaccine in the previous season. If you were vaccinated last year, you don’t need another shot this year.
Whether a booster will eventually be recommended remains an open question. At least one manufacturer is running clinical trials testing a booster dose given one year after the initial shot, looking at both safety and immune response. But until those results lead to new guidelines, one dose is all that’s recommended.
RSV Protection During Pregnancy
Pregnant individuals can receive a single dose of the RSV vaccine to help protect their newborn. The timing matters: it’s given during pregnancy so that protective antibodies transfer to the baby before birth. If you received an RSV vaccine during a previous pregnancy, the CDC does not currently recommend getting another dose in a later pregnancy.
How Infant Protection Works Differently
Babies and young toddlers don’t receive an RSV vaccine. Instead, they get a preventive antibody injection that provides passive protection for one RSV season. This is typically given in October or November, just before RSV season begins, or within the first week of life for babies born during the October through March season.
Most infants only need this once. However, certain higher-risk children between 8 and 19 months old, including those with chronic lung disease, severe immune deficiency, cystic fibrosis with significant lung involvement, or American Indian and Alaska Native children, are recommended to receive a second dose before their second RSV season. This protection is not recommended for anyone 20 months or older.
How This Compares to Other Vaccines
The RSV vaccine’s one-and-done schedule can feel unusual if you’re used to annual flu shots. The difference comes down to how the virus behaves. Influenza mutates rapidly, requiring a reformulated vaccine each year. RSV is more genetically stable, so a single dose can maintain useful protection across multiple seasons. That said, immunity does wane over time, and future guidelines could eventually include a booster. For now, if you’ve had your RSV shot, you’re covered.