The RSV vaccine is a one-time shot, not an annual one. Unlike the flu vaccine, which you need every year, the current CDC recommendation is a single dose with no booster or repeat dose at this time. If you’ve already received one dose, you’re considered fully vaccinated.
Who Needs the Vaccine
The CDC recommends a single dose of RSV vaccine for all adults 75 and older, and for adults 50 to 74 who have an increased risk of severe RSV illness. Risk factors in that younger group include chronic lung or heart disease, a weakened immune system, living in a nursing home, and other conditions that make RSV complications more likely.
This is a shift from the original 2023 guidance, which set the age threshold at 60. The current recommendations narrowed the eligible group while also making the vaccine a stronger, more universal recommendation for those who do qualify.
Why It’s Not Annual Like the Flu Shot
RSV doesn’t mutate as rapidly as influenza, so the vaccine doesn’t need to be reformulated each year to match new strains. Clinical trials tracked participants for roughly 17 to 23 months on average, and the protection held up well enough that regulators saw no need for yearly revaccination. The CDC and its advisory committee are continuing to monitor whether a second dose might be beneficial down the road, but for now the official position is clear: one dose is enough, and you should not get a second one.
Protection for Infants
Babies and young children don’t get the same vaccine adults do. Instead, most infants are protected with nirsevimab, an antibody injection given before or during RSV season (typically October through March). This isn’t technically a vaccine. It delivers ready-made antibodies rather than training the immune system to produce its own. Most healthy infants need just one dose in their first RSV season.
A smaller group of higher-risk children may receive a second dose before their second RSV season. This includes children with chronic lung disease of prematurity who still needed medical support in the six months before the season, children with severe immune deficiencies, children with cystic fibrosis and significant lung involvement or low weight, and American Indian or Alaska Native children. For everyone else, one dose during infancy covers the period of greatest vulnerability.
RSV Vaccination During Pregnancy
Pregnant women can receive an RSV vaccine during weeks 32 through 36 of pregnancy to pass protective antibodies to the baby before birth. This is an alternative to the infant receiving nirsevimab after delivery. The baby gets one or the other, not both.
If you received the maternal RSV vaccine during a previous pregnancy, you do not currently need another dose in a later pregnancy. The CDC is still evaluating whether revaccination in subsequent pregnancies would offer enough additional benefit to justify it, but for now the recommendation is one dose across all pregnancies. If a mother was not vaccinated during her current pregnancy, the infant can receive nirsevimab instead.
What Could Change
The one-dose recommendation isn’t necessarily permanent. The CDC’s Advisory Committee on Immunization Practices has stated it will reevaluate whether additional doses are needed as more long-term data comes in. One of the clinical trials even included a subgroup that received a second dose 12 months after the first, though that data hasn’t yet changed the official guidance. If protection turns out to fade meaningfully after a few years, a booster recommendation could follow. For now, though, one shot and you’re done.