Duration of Protection for Arexvy (RSV Vaccine)
A single dose of Arexvy provides protection for at least two consecutive RSV seasons, and no additional doses are currently recommended. 1
Current Evidence on Duration of Protection
Single-dose protection extends through at least two RSV seasons based on current clinical trial and observational data. 1 The ACIP has explicitly stated that adults who have already received RSV vaccination should not receive another dose at this time. 1
Key Clinical Trial Findings
- Arexvy demonstrated approximately 83% protection in adults during initial clinical evaluation. 2
- The vaccine maintains effectiveness for up to two RSV seasons based on available follow-up data. 2
- Median per-participant follow-up time in clinical trials extended to 18.8 months, providing robust data on durability of protection. 1
- Real-world vaccine effectiveness against RSV-associated hospitalization during the first season ranged from 75% to 82% among adults ≥60 years. 1
Future Revaccination Considerations
The need for additional RSV vaccine doses will be evaluated by ACIP in the future as more data become available. 1 Before making recommendations on revaccination, ACIP has identified several critical data gaps that need to be addressed:
- Additional data on duration of protection beyond two seasons 1
- Evidence on immune response after revaccination 1
- Updated safety analyses incorporating the full 2023-2024 RSV season 1
- Immunogenicity data in adults with immunocompromise 1
Important Clinical Caveats
Vaccine effectiveness may wane over time, which is expected for a virus characterized by short-term natural immunity. 3 However, modeling studies demonstrate that even with waning, the efficacy remains clinically meaningful over placebo through at least two seasons. 3
The benefit-risk analysis shows that estimated preventable RSV-associated hospitalizations, ICU admissions, and deaths over two consecutive RSV seasons per 1 million vaccine doses substantially exceed potential vaccine-attributable adverse events. 1
Optimal Timing for the Single Dose
Vaccination should ideally occur in late summer or early fall (August-October), just before RSV season begins, to maximize protection. 1 However, eligible adults who have not been vaccinated may receive the vaccine at any time of year. 1
Do not delay vaccination while waiting for the "perfect" timing—protection begins after the single dose and extends through multiple seasons. 1