The RSV vaccine for seniors is a one-dose shot that protects against respiratory syncytial virus, a common infection that causes thousands of hospitalizations and several thousand deaths among older adults each year. Three vaccines are currently FDA-licensed for adults 50 and older: GSK’s Arexvy, Pfizer’s Abrysvo, and Moderna’s mResvia. There is no preference for which one you receive.
Why RSV Is Dangerous for Older Adults
Most people think of RSV as a childhood illness, and it does hit infants hard. But RSV is also a serious threat to adults over 60, especially those with weakened immune systems or chronic health conditions affecting the heart or lungs. In older adults, what starts as cold-like symptoms can progress to pneumonia or bronchiolitis, sometimes requiring hospitalization. The risk climbs steeply after age 75.
Unlike the flu, RSV didn’t have a vaccine option for adults until mid-2023. That gap meant millions of older adults faced RSV seasons with no specific protection beyond hand-washing and avoiding sick contacts.
Who Should Get the Vaccine
All three RSV vaccines are recommended for adults 50 and older. If you’re 75 or older, the case for vaccination is strongest because your risk of severe RSV disease is highest. Adults between 60 and 74 who have chronic lung disease, heart disease, or compromised immune function also fall squarely into the group that benefits most.
Two of the vaccines, Abrysvo and mResvia, are also FDA-approved for adults ages 18 to 49 who are at increased risk for RSV-related lower respiratory tract infection. This broader approval reflects the understanding that age alone isn’t the only risk factor.
How the Vaccines Work
RSV gets into your cells using a protein on its surface called the fusion (F) protein. All three vaccines target this protein, training your immune system to recognize and neutralize the virus before it can cause serious illness. Arexvy and Abrysvo are protein subunit vaccines, meaning they contain a lab-made version of the F protein itself. Your immune system sees the protein, mounts a response, and builds antibodies against it.
Moderna’s mResvia takes a different approach. It uses mRNA technology, the same platform behind the Moderna COVID-19 vaccine. Instead of delivering the protein directly, it gives your cells instructions to produce the F protein temporarily, triggering the same antibody response. The end result is similar across all three: your body learns to block the virus at the point of entry.
How Well the Vaccines Work
Clinical trial data pooled from the Arexvy and Abrysvo trials shows strong protection. Among adults 75 and older, vaccination reduced the rate of RSV-related lower respiratory tract disease by about 69% compared to placebo. For adults aged 60 to 74 with underlying health conditions that put them at higher risk, efficacy was even better, at roughly 73%. Both of these findings were rated as high-certainty evidence by the CDC’s advisory committee.
These numbers represent protection against the kind of RSV illness that settles deep in the lungs, not just sniffles or a sore throat. That’s the outcome that matters most, since lower respiratory tract disease is what sends older adults to the hospital.
What to Expect After the Shot
The RSV vaccine is given as a single dose. Common side effects are typical of most vaccines: soreness at the injection site, fatigue, headache, and muscle aches. These generally resolve within a day or two.
There is one rare but serious safety signal worth knowing about. The FDA identified a small increased risk of Guillain-Barré syndrome (GBS) within the 42 days following vaccination with either Arexvy or Abrysvo. GBS is a rare disorder where the immune system damages nerve cells, causing muscle weakness and sometimes temporary paralysis. The estimated excess risk is about 7 to 9 additional GBS cases per million doses in people 65 and older. To put that in perspective, that’s fewer than 1 in 100,000 vaccinated people. The FDA has added a GBS warning to the prescribing information for both vaccines. During clinical trials, individual GBS cases appeared within 7 to 9 days of vaccination.
How Long Protection Lasts
This is still an open question. Arexvy and Abrysvo were first licensed in May 2023, and mResvia followed in June 2024, so long-term follow-up data is limited. The CDC has stated openly that it is still learning how long RSV vaccines provide protection. For now, the vaccine is given as a single dose rather than annually, but guidance on whether a booster will eventually be needed is expected to evolve as more data comes in.
Because RSV typically peaks during fall and winter in most of the United States, getting vaccinated before RSV season starts, ideally in late summer or early fall, makes the most practical sense. Your pharmacist or doctor can help you time it alongside other seasonal vaccines.
Choosing Between the Three Vaccines
The CDC does not recommend one RSV vaccine over another. All three target the same viral protein, all are given as a single injection, and all are approved for adults 50 and older. The choice often comes down to what your pharmacy or clinic has in stock. If you have a strong preference for or against mRNA technology, that narrows the options: mResvia uses mRNA, while Arexvy and Abrysvo use traditional protein subunit technology. But in terms of the protection they offer, all three are considered comparable options.