FDA Approves Moderna RSV Vaccine mRNA-1345 for Older Adults
The FDA has approved Moderna's mRNA-1345 vaccine for respiratory syncytial virus (RSV) in older adults, enhancing protection against this serious respiratory illness.
Medically Reviewed
by Dr. James Morrison, Chief Medical Officer (MD, FACP, FACC)
Reviewed on: April 07, 2026
The U.S. Food and Drug Administration (FDA) has approved mRNA-1345, Moderna's messenger RNA vaccine targeting respiratory syncytial virus (RSV), for adults aged 60 years and older. The approval follows a comprehensive FDA review of Phase 3 clinical trial data demonstrating significant efficacy in preventing RSV-associated lower respiratory tract disease in the target population. This mRNA-1345 authorization represents a key milestone in vaccinology and addresses a substantial unmet medical need, as RSV remains a leading cause of hospitalization and morbidity in older adults.
Drug Overview
mRNA-1345 is an mRNA-based vaccine developed by Moderna that encodes the stabilized prefusion form of the respiratory syncytial virus F glycoprotein. The vaccine leverages Moderna's mRNA technology platform, the same foundational approach used in their authorized COVID-19 vaccines. By encoding the prefusion F protein, mRNA-1345 is designed to elicit robust neutralizing antibody responses and cellular immunity against RSV. The vaccine is indicated for immunization of adults aged 60 years and older to prevent respiratory illness caused by RSV, a major pathogen in infectious disease management in older populations.
Clinical Insights
The FDA approval was supported by data from a large, randomized, placebo-controlled Phase 3 clinical trial evaluating mRNA-1345 in adults aged 60 years and older. [Source: U.S. Food and Drug Administration] The trial met its primary efficacy endpoint, demonstrating significant efficacy in preventing RSV-associated lower respiratory tract disease. The vaccine exhibited a favorable safety and tolerability profile consistent with class-typical mRNA vaccine adverse events. Commonly reported adverse events were mild to moderate in severity and transient, including injection site reactions, fatigue, headache, and myalgia. The Phase 3 safety review identified no unexpected safety signals, supporting the favorable benefit-risk profile that informed the FDA's approval decision.
Regulatory Context
mRNA-1345 was reviewed by the FDA through submission of a Biologics License Application (BLA), the regulatory pathway for vaccines and other biological products. The approval followed comprehensive evaluation of preclinical, Phase 1, Phase 2, and Phase 3 clinical data by the FDA's Center for Drug Evaluation and Research (CDER) and Center for Biologics Evaluation and Research (CBER). Given the significant public health burden of RSV in older adults and the substantial unmet medical need for an effective preventive vaccine, the FDA prioritized its review of this application. The authorization reflects the agency's determination that mRNA-1345 meets the statutory standards for safety, efficacy, and manufacturing quality required for licensure.
Market Impact
The FDA approval of mRNA-1345 positions Moderna as a key competitor in the emerging RSV vaccine market for older adults. The vaccine enters a competitive landscape that includes late-stage RSV vaccine candidates from Pfizer and GSK, both targeting the same older adult population. RSV represents a significant disease burden in adults aged 60 and older, with the virus being a leading cause of hospitalization and respiratory morbidity in this age group. The approval of mRNA-1345 provides healthcare systems and older adults with an effective preventive option addressing a previously limited set of RSV prevention strategies. Market potential is substantial given the size of the older adult population in the United States and the high incidence of RSV-associated illness in this demographic.
Future Outlook
Following FDA approval, mRNA-1345 will enter the commercial market for older adults. Moderna may pursue additional clinical studies to evaluate the vaccine's durability of protection, potential use in combination with other vaccines recommended for older adults, or efficacy in immunocompromised populations. Competitive RSV vaccine approvals from Pfizer and GSK are anticipated in coming months, which will shape the evolving RSV vaccine market. Real-world effectiveness data and health economic studies will likely emerge to inform clinical practice guidelines and vaccination recommendations. Label expansions or additional indications may be explored as clinical evidence accumulates post-approval.
Frequently Asked Questions
What is mRNA-1345 and how does it work?
mRNA-1345 is an mRNA vaccine that encodes the prefusion F protein of respiratory syncytial virus. Once administered, the vaccine instructs cells to produce the RSV F protein, which stimulates the immune system to generate neutralizing antibodies and cellular immune responses protective against RSV infection.
Who is eligible to receive mRNA-1345?
The FDA-approved indication is for adults aged 60 years and older. Healthcare providers should refer to the prescribing information and clinical guidelines for specific recommendations regarding patient selection and vaccination strategies.
What were the key clinical trial results?
The Phase 3 trial demonstrated significant efficacy of mRNA-1345 in preventing RSV-associated lower respiratory tract disease in adults aged 60 and older. The vaccine was well tolerated, with adverse events predominantly mild to moderate and transient in nature.
How does mRNA-1345 compare to other RSV vaccines?
mRNA-1345 utilizes Moderna's mRNA platform encoding the stabilized prefusion F protein, potentially offering robust immunogenicity and a favorable safety profile. Competitive RSV vaccines from Pfizer and GSK employ different technological approaches and are at various stages of regulatory review.
What are the common side effects of mRNA-1345?
Commonly reported adverse events include injection site reactions, fatigue, headache, and myalgia. These events were generally mild to moderate in severity and resolved within a few days. Serious adverse events were not identified as unexpected safety concerns in the Phase 3 trial.
References
- U.S. Food and Drug Administration. Center for Biologics Evaluation and Research. Approval of mRNA-1345 (Moderna RSV vaccine). [Regulatory decision document; specific date and reference number to be confirmed from official FDA communications].
- Moderna, Inc. Clinical trial data for mRNA-1345: Phase 3 efficacy and safety results in adults aged 60 years and older. [Company clinical data on file; specific publication or press release to be referenced].
- National Institute of Allergy and Infectious Diseases (NIAID). Respiratory Syncytial Virus (RSV) and Older Adults. [Public health resource on RSV epidemiology and disease burden].
References
- U.S. Food and Drug Administration. FDA approval. Accessed 2026-04-07.
Senior Medical Editor
Dr. Sarah Chen is a board-certified internist and former FDA clinical reviewer with 15+ years of experience in pharmaceutical regulatory affairs. She received her MD from Johns Hopkins and her PhD in ...
