Evaluating the efficacy, safety, and immunogenicity of FDA-approved RSV vaccines: a systematic review of Arexvy, Abrysvo, and mResvia.

BACKGROUND

Respiratory Syncytial Virus (RSV) poses a major health threat to older adults, pregnant women, and high-risk populations. We systematically evaluated the efficacy, immunogenicity, and safety of three FDA-approved RSV vaccines: Arexvy, Abrysvo, and mResvia.

METHODS

Following PRISMA 2020 guidelines, we searched PubMed, ClinicalTrials.gov, FDA, and Vaccine Adverse Event Reporting System (VAERS) up to March 2025. Of 1,250 identified records, 24 studies (14 RCTs, 7 observational, 3 post-marketing) met inclusion criteria. Risk of bias was assessed using the Cochrane RoB tool and Newcastle-Ottawa Scale. PROSPERO registration: CRD420250651132.

RESULTS

Included studies enrolled over 50,000 participants across North America, Europe, Asia, and Latin America. Arexvy reduced RSV-related hospitalizations in older adults by 60-65% (95% CI: 56-66%); Abrysvo showed 58-63% efficacy in older adults and 68-72% protection against infant RSV hospitalization via maternal immunization. mResvia demonstrated 55-58% efficacy against RSV illness. All vaccines induced 5-7-fold increases in neutralizing antibody titers, with responses sustained for up to 12 months. Safety profiles were favorable: local injection site pain occurred in ~23-29%, systemic symptoms in 7-11%, and serious adverse events in <1%. No new safety concerns were identified in post-marketing surveillance.

CONCLUSION

FDA-approved RSV vaccines provide robust protection against RSV in high-risk populations, with sustained immunogenicity and acceptable safety. While findings are promising, generalizability to underserved regions remains limited, and long-term effectiveness data are still emerging. Continued real-world monitoring and head-to-head comparisons are needed to inform global immunization strategies.

CLINICAL TRIAL REGISTRATION

https://www.crd.york.ac.uk/PROSPERO/view/, identifier CRD420250651132.