Yes, Arexvy is currently a one-time dose. The CDC recommends a single dose for eligible adults, and people who have already received one dose have completed their vaccination. No booster or annual shot is recommended at this time.
Who Is Eligible for the Single Dose
The CDC recommends Arexvy for all adults 75 and older and for adults 50 to 74 who are at increased risk of severe RSV illness. The FDA approval is broader: it covers adults 60 and older, as well as adults 18 through 59 who are at increased risk for RSV-related lower respiratory tract disease. Your eligibility depends on both your age and any underlying conditions that make RSV more dangerous for you.
Pfizer’s competing RSV vaccine, Abrysvo, follows the same single-dose recommendation. The CDC evaluated both protein-based RSV vaccines together and concluded that one dose of either product is the appropriate course for eligible adults.
How Long One Dose Protects You
Clinical trial data show that a single dose of Arexvy reduced the risk of RSV-related lower respiratory tract disease by about 74.6% during the first RSV season. Protection held up reasonably well into a second season: efficacy over two full seasons was estimated at 67% to 75%, depending on how the data were adjusted. That gradual decline is expected with most vaccines, and it’s one reason the CDC continues to monitor whether a booster will eventually be needed.
For now, one dose is considered sufficient. The CDC has stated that “surveillance and evaluation activities are ongoing to determine whether adults might benefit from receiving additional RSV vaccine doses in the future.” If guidelines change, they’ll be updated, but there is no timeline for a booster recommendation.
Why It Isn’t an Annual Vaccine
Unlike the flu shot, Arexvy is not designed to be given every year. RSV doesn’t mutate as rapidly as influenza, so the vaccine doesn’t need to be reformulated each season. The single dose generates an immune response that lasts well beyond one winter. The CDC has been explicit on this point: “The RSV vaccine is not currently an annual vaccine.” If you’ve already received your shot, you should not get another dose unless future guidance says otherwise.
Common Side Effects After the Shot
Most side effects from Arexvy are mild and resolve within a few days. In the phase 3 trial, about 61% of recipients reported injection-site pain, compared to 9% in the placebo group. Other common reactions included fatigue (34%), muscle aches (29%), headache (27%), and joint pain (18%). Fever was uncommon, occurring in only 2% of vaccinated participants. Severe reactions (grade 3) were rare across all categories, each affecting roughly 1% to 2% of recipients.
These numbers are in line with what you’d expect from other adult vaccines. Side effects typically appear within a day or two of the injection and clear up on their own.