Abrysvo vs. mRESVIA: which RSV vaccine is right for you?
Adults 60 and older now have two FDA-approved RSV vaccines to choose from: Abrysvo (Pfizer) and mRESVIA (Moderna). Both protect against severe lower respiratory disease caused by RSV. They work differently, have different side effect profiles, and may be more or less available depending on where you get vaccinated. Here's what you need to know to have an informed conversation with your doctor.
The basics: what kind of vaccine is each?
Abrysvo is a protein subunit vaccine. It contains a stabilized form of the RSV fusion protein — the spike-like structure RSV uses to enter cells — which your immune system learns to recognize and fight. This is a traditional vaccine technology, similar in concept to hepatitis B and pertussis vaccines.
mRESVIA is an mRNA vaccine, the same platform technology used in the COVID-19 vaccines from Moderna and Pfizer. It delivers genetic instructions for your cells to produce the RSV fusion protein, triggering an immune response. mRESVIA is the first mRNA vaccine approved for a disease other than COVID-19.
How do the efficacy numbers compare?
Both vaccines were studied in large randomized trials in adults 60+ and showed meaningful protection against RSV lower respiratory tract disease (LRTD) — which includes bronchitis and pneumonia from RSV, the outcomes that cause hospitalizations.
From their respective clinical trials:
- Abrysvo: approximately 67–85% efficacy against RSV LRTD with two or more symptoms in adults 60+
- mRESVIA: approximately 83% efficacy against RSV LRTD in adults 60+
A note on comparing trial numbers: These trials were conducted at different times, in different seasons, and against different circulating RSV strains. Direct head-to-head comparison of the efficacy percentages isn't meaningful — a 67% result in one trial and an 83% in another don't tell you which vaccine is "better," only that both showed significant protection. Neither vaccine has been tested head-to-head.
Side effects: how do they differ?
Both vaccines can cause injection site reactions (soreness, redness) and systemic symptoms (fatigue, headache, muscle aches). The key difference is in degree:
- mRESVIA tends to produce more pronounced reactogenicity — the arm soreness, fatigue, and flu-like symptoms that reflect an active immune response. This is consistent with what's been seen with other mRNA vaccines. Symptoms typically resolve in 1–2 days.
- Abrysvo generally produces milder side effects in most people, though individual variation is significant.
Neither vaccine has been associated with serious safety signals in the trial populations of adults 60+. Guillain-Barré syndrome (GBS) was a signal of concern that appeared in early Abrysvo data — subsequent analysis has not established a causal link, but it remains an area of ongoing surveillance. Discuss this with your doctor if you have a history of GBS.
Who each vaccine may be a better fit for
There is no universal right answer, but some considerations that may favor one over the other:
You might lean toward Abrysvo if:
- You're sensitive to injection reactions or have had difficult experiences with mRNA COVID vaccines
- You have a history of GBS (discuss with your doctor — this may or may not apply)
- You want a vaccine technology with a longer track record in this age group
You might lean toward mRESVIA if:
- You've had no issues with mRNA COVID vaccines and want a similar platform
- Abrysvo is not available at your pharmacy or doctor's office
- Your doctor recommends it based on your specific health profile
Do you need to get one every year?
As of 2026, both RSV vaccines for adults 60+ are approved as a single dose. There is no established recommendation to revaccinate annually, unlike flu. The durability of protection is still being studied in ongoing follow-up data from the original trials. The CDC will update guidance as longer-term data becomes available.
Can you get the RSV vaccine and flu shot at the same time?
Yes. The RSV vaccine can be given at the same visit as the flu vaccine (and the COVID vaccine). Getting them together is convenient and does not appear to meaningfully reduce the immune response to either. If you're concerned about managing potential side effects from multiple vaccines at once, it's reasonable to space them out by a week — ask your pharmacist or doctor.
What if you already got one RSV vaccine — do you need the other?
No. Current guidance is one RSV vaccine for adults 60+, not a series from two different manufacturers. If you already received Abrysvo, you don't need mRESVIA (and vice versa). If you're not sure whether you've received an RSV vaccine, check your immunization records — it should be documented there.
Not medical advice. Vaccine recommendations evolve as new data emerges. Always confirm current guidance with your doctor or pharmacist before making vaccination decisions.