Research Analysis · Immune aging
RSV vaccines reduce respiratory disease. Separate trials cannot rank them
Arexvy, Abrysvo and mResvia each reduced a trial-defined RSV respiratory endpoint. Their studies used different definitions and follow-up, while current CDC guidance is age- and risk-based, product-neutral and not an annual schedule.
Discovery, counterevidence, claim mapping, identifiers, funding, correction state and prose were reviewed before release.
Evidence at a glance
Three product-specific trial programs
- Study type
- Three separate randomized placebo-controlled phase 2–3 or phase 3 trials, plus public-health review and postauthorization safety surveillance
- Studied in
- Humans
- Participants / sample
- 24,966 for Arexvy; 34,284 for Abrysvo; 35,541 for mResvia
- Publication status
- Peer reviewed; registries reverified; no featured correction or retraction identified as of verification
- Outcome type
- Product- and protocol-defined RSV lower-respiratory disease or illness; acute respiratory disease; safety
- Development stage
- Three licensed vaccines under current one-dose age- and risk-based guidance
- Conflicts / funding
- GSK, Pfizer and Moderna funded their respective pivotal trials
- Our assessment
- Randomized product-specific efficacy evidence; no head-to-head ranking or established longevity effect
- Reporting confidence
- High confidence in scoped trial translation; durability and repeat-dose evidence continue to mature
Read this first
Four takeaways
- Each licensed vaccine reduced its own trial-defined RSV lower-respiratory endpoint relative to placebo.
- The percentages are not a league table: case definitions, populations, surveillance and analysis times differed.
- CDC's February 24, 2026 guidance recommends one dose for everyone 75+ and adults 50–74 at increased risk, with no product preference.
- RSV vaccination is not currently annual, repeat dosing is not currently recommended, and none of the trials established slower aging or longer life.
Product and outcome boundaries
What can—and cannot—be compared
Can compare
Within each trial, vaccine and placebo groups were randomized under one protocol and case definition.
Cannot rank
Percentages from separate trials do not establish comparative superiority among products.
Current guidance
Age 75+ is universal; age 50–74 is risk-based. CDC states no product preference.
Still uncertain
Optimal revaccination timing, some oldest-old and frail subgroup effects, rare-event precision and longevity outcomes.
Descriptive product map
Keep each result inside its trial
The table explains the pivotal analyses. It does not score, recommend or rank products.
| Product / trial | Platform and population | Primary respiratory result | Important limit |
|---|---|---|---|
| Arexvy / AReSVi-006 | Adjuvanted RSVPreF3 OA; 24,966 adults 60+ | 7 versus 40 LRTD cases; 82.6% efficacy over median 6.7 months | Severe-outcome estimate used few events; protection wanes over time |
| Abrysvo / RENOIR | Bivalent RSVpreF; 34,284 adults 60+ | 66.7% efficacy for ≥2 symptoms; 85.7% for ≥3 symptoms | The ≥3-symptom estimate was based on 2 versus 14 cases |
| mResvia / ConquerRSV | mRNA-1345; 35,541 adults 60+ | 83.7% efficacy for ≥2 symptoms; 82.4% for ≥3 symptoms | Median 112-day primary follow-up; longer-term protection waned |
LRTD means lower-respiratory-tract disease. Similar labels can still hide different symptom and adjudication rules. Cross-trial percentages are descriptive only.
The bottom line
All three products have randomized evidence that they reduce protocol-defined RSV respiratory disease relative to placebo. The evidence supports product-specific benefits, not a universal ranking. Current U.S. guidance treats vaccination as one dose for defined age and risk groups, not an annual routine.
Why this matters
RSV can cause serious illness in older adults, especially with frailty or chronic disease. The arrival of three vaccine platforms created useful options and a predictable temptation to compare headline percentages as though the trials were one contest. They were not.
What researchers did
AReSVi-006 randomized adults 60 or older to adjuvanted RSVPreF3 OA or placebo. RENOIR tested bivalent RSVpreF against placebo. ConquerRSV tested mRNA-1345 against placebo. Each program defined lower-respiratory disease, symptom thresholds, surveillance and analysis timing in its own protocol.
What they found
Arexvy's first-season analysis found 7 versus 40 lower-respiratory-disease cases. Abrysvo reported 66.7% efficacy under a two-symptom definition and 85.7% under a three-symptom definition. mResvia reported 83.7% and 82.4% under its corresponding definitions. Confidence intervals widened when event counts were small.
How strong is the evidence?
These are large randomized human trials, strong evidence for their exact product, comparator, case definition, population and follow-up. They are weaker for oldest-old or frail subgroups with few participants, rare harms, direct product comparison, hospitalization or mortality when those endpoints were sparse or the trials were not powered for them.
What this evidence does not show
It does not show that one product is universally best, that efficacy percentages can be compared without protocol context, that vaccination should be repeated annually, or that preventing RSV disease restores an aging immune system, increases healthspan or lengthens life.
Safety, regulation, and funding
Short-term local and systemic reactions were more common with vaccination in the pivotal studies, while serious-event proportions were generally similar. FDA later required Guillain–Barré syndrome warnings for Arexvy and Abrysvo after observational estimates of about 7 and 9 excess cases per million doses, respectively; FDA said the evidence suggested increased risk but was insufficient to establish causality. That signal should not be transferred to mResvia. Each pivotal trial was manufacturer-funded.
What happens next
Longer follow-up and postauthorization surveillance will refine durability, severe-disease and rare-safety estimates. CDC continues to evaluate whether and when another dose may be useful. Direct comparative studies would be needed before a defensible product ranking.
Educational boundary
This article explains population evidence and a dated guidance snapshot. It is not personalized medical advice and does not select a product or timing for an individual. Current risk factors, history, contraindications, availability and recommendations belong in a clinician or pharmacist discussion.
Primary sources
Sources, roles and limits
- Arexvy / RSVPreF3 OA pivotal trial
- Identifier
- PMID:36791160 · DOI:10.1056/NEJMoa2209604 · NCT04886596
- Role
- Primary product-specific randomized support
- Limitation
- First-season definitions and follow-up; not a head-to-head comparison.
- Abrysvo / RSVpreF pivotal trial
- Identifier
- PMID:37018468 · DOI:10.1056/NEJMoa2213836 · NCT05035212
- Role
- Primary product-specific randomized support
- Limitation
- Small case count for the three-symptom definition.
- mResvia / mRNA-1345 pivotal trial
- Identifier
- PMID:38091530 · DOI:10.1056/NEJMoa2307079 · NCT05127434
- Role
- Primary product-specific randomized support
- Limitation
- Short primary-analysis follow-up and no powered mortality result.
- CDC adult RSV clinical guidance
- Verified snapshot
- February 24, 2026
- Role
- Current age/risk, product-neutral and repeat-dose context
- Limitation
- Guidance can change and is not individualized advice.
- FDA Guillain–Barré syndrome warning
- Role
- Postauthorization safety and labeling context
- Limitation
- Observational signal with causal uncertainty; product-specific.
Connected topics
Continue through the knowledge system
Continue with real coverage
Keep reading
These are learning paths, not rankings, recommendations, or evidence that the stories support one another.
Another older-adult vaccine result with formulation boundaries
High-dose flu vaccine reduced influenza—not immune aging
The randomized result was 1.4% versus 1.9% influenza across two seasons, not proof of immune rejuvenation or longer life.
Evidence scopeHuman infection outcome · large randomized trial
How evidence changes with age, baseline risk and prevention setting
Statin evidence changes with age, risk and prevention setting
Evidence is clearer after vascular disease than for starting primary prevention after age 75, and it does not establish longer life.
Evidence scopeHuman clinical outcomes · trials and pooled evidence
A different older-adult intervention with bounded function evidence
Creatine added to resistance training may improve some strength measures—not longevity
Pooled short trials found modest lean-mass and strength gains, while a related one-year analysis found no additional benefit.
Evidence scopeHuman function · trials and pooled evidence
Disclosures and history
- August 2, 2026 — source discovery and independent verification completed before prose drafting.
- August 2, 2026 — product, endpoint, guidance, safety, funding and longevity boundaries reviewed.
- Corrections: no featured correction or retraction identified for the three pivotal papers as of publication.