Moderna's mRESVIA revaccination data show durable immune response in adults 60+
Interim results from Moderna's Phase 3 booster study suggest a second mRESVIA dose restores RSV antibody levels comparable to the primary shot, with full data due later in 2026.
Executive Summary
- A Phase 3 study testing whether a second dose of Moderna's RSV vaccine restores antibody protection in older adults has finished enrollment and follow-up, with interim results already pointing to a tolerable, effective booster.
- The result speaks to whether RSV vaccination becomes a recurring seasonal product rather than a one-time shot, a distinction that shapes the durability of Moderna's RSV franchise.
- The fuller dataset behind the interim readout is expected later in 2026, and it will need to confirm the antibody response held up across the full study population, not just the early look.
- No other sponsor has publicly tested this specific revaccination schedule question yet, leaving Moderna positioned to set the frame of reference other RSV vaccine programs will be measured against.
The trial
The study, registered as NCT07117487, enrolled adults 60 and older who had already received a single dose of a licensed protein-subunit RSV vaccine, either GSK's Arexvy or Pfizer's Abrysvo, at least 12 months earlier. Participants then received mRNA-1345, Moderna's mRESVIA, to test whether a second RSV vaccine dose, from a different vaccine platform than the first, restores neutralizing antibody levels. The trial enrolled 507 participants against a 507 target, moved from Recruiting to Active, not recruiting on January 30, 2026, and reached Completed status on May 4, 2026, with a primary completion date of March 27, 2026. NCT07117487A Study of mRNA-1345 Following a Primary Dose of a Licensed Protein Subunit Respiratory Syncytial Virus (RSV) Vaccine in Adult Participants ≥60 Years of AgeNCT07117487
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
The endpoint bar
The registered primary endpoints measure geometric mean titer of RSV-A and RSV-B neutralizing antibodies at Day 29, alongside safety measures covering medically attended adverse events, serious adverse events, and adverse events of special interest. These are immunogenicity measures, not a clinical efficacy endpoint like confirmed RSV infection or hospitalization, so the trial is built to establish an immune-response bridge rather than a direct disease-prevention result. NCT07117487A Study of mRNA-1345 Following a Primary Dose of a Licensed Protein Subunit Respiratory Syncytial Virus (RSV) Vaccine in Adult Participants ≥60 Years of AgeNCT07117487
What's already disclosed
Moderna presented interim results at the European Congress of Clinical Microbiology and Infectious Diseases (ESCMID) on April 18, 2026, describing the revaccination dose as well tolerated with no new safety concerns, and reporting that immunogenicity data suggest revaccination may restore protection comparable to primary-dose levels. That characterization sits with immature data still maturing toward the full analysis. Moderna's January 12, 2026 pipeline update at the J.P. Morgan Healthcare Conference had already flagged this study as one of several 2026 pivotal readouts across its infectious disease, oncology, and rare disease portfolios. ModernaModerna Provides Business and Pipeline Updates at 44th Annual J.P. Morgan Healthcare ConferenceJan 12, 2026
Operational read
The enrollment count moved from 500 to 507 between the registered target and the actual figure, a change the operational model classifies within its routine band since increases below 20% are not flagged. The trial finished with no completion-date slippage against its own registered date and no post-completion endpoint changes, which points to a clean execution record heading into the fuller data disclosure. NCT07117487A Study of mRNA-1345 Following a Primary Dose of a Licensed Protein Subunit Respiratory Syncytial Virus (RSV) Vaccine in Adult Participants ≥60 Years of AgeNCT07117487
The competitive frame
No trial identified shares this precise revaccination-timing design, and Moderna's own competitive search returned no head-to-head comparator arms for mRESVIA in RSV. The nearest readthrough sits with Pfizer's ongoing Phase 3 study of bivalent RSV revaccination in subsequent pregnancies and a Phase 3 study of RSVpreF in India, both of which test durability and repeat-dosing questions for a different RSV vaccine platform. The RSV vaccine field otherwise splits between protein-subunit shots from GSK and Pfizer, already approved, and a small set of RNA-based candidates in earlier-phase testing from GSK, Abogen Biosciences, and Shenzhen Shenxin Biotechnology, none of which has read out a revaccination result yet. Against that landscape, a full dataset confirming durable antibody restoration across all 507 participants would be the evidence that establishes RSV revaccination as a viable annual or biennial strategy rather than an open question the field is still testing.
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.