FDA-Approved RSV Vaccines and Monoclonal Antibodies: Labeled Indications
Respiratory syncytial virus prophylaxis now spans two regulatory categories — active-immunization vaccines and passive-immunization monoclonal antibodies — licensed under separate BLAs with distinct age, risk, and maternal-use boundaries. For regulatory and clinical teams, the labeled indication statements determine which populations a product may be promoted for, how comparative claims against competing RSV products can be framed, and where label expansions have already established precedent for age-group extensions.
The analysis below compiles the FDA-licensed RSV vaccines and monoclonal antibodies, identifying each product's proper name, sponsor, BLA number, and initial U.S. approval date, then sets out the currently indicated populations as stated in approved labeling. Pediatric and older-adult indications are treated separately, with attention to how each product's indication has evolved since first licensure.
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FDA-approved RSV vaccines and monoclonal antibodies: pediatric and older-adult indications
The FDA has licensed two distinct classes of products for respiratory syncytial virus (RSV): active-immunization vaccines aimed primarily at older adults and pregnant individuals (to protect infants), and passive-immunization monoclonal antibodies aimed at infants and young children. As of the current labeling, six products are approved: three vaccines (Arexvy, Abrysvo, mRESVIA) and three monoclonal antibodies (Synagis, Beyfortus, Enflonsia). All six are indicated for the prevention of RSV-associated lower respiratory tract disease (LRTD); none is indicated for treatment of established RSV infection.
RSV vaccines (active immunization)
All three vaccines were first licensed for adults 60 years of age and older, and the labeling for each has since evolved. Two of the three (Arexvy, mRESVIA) now extend to adults 18 through 59 years at increased risk, and one (Abrysvo) additionally carries a maternal indication that is the only route by which any of these products protects infants.
| Product (proper name) | Sponsor / BLA | Initial U.S. approval | Current indicated populations |
|---|---|---|---|
| Arexvy (RSV vaccine, adjuvanted; recombinant prefusion F subunit) | GlaxoSmithKline; BLA 125775 | 2023 (May 3, 2023 review completion) 3336 | Individuals 60 years and older; individuals 18 through 59 years at increased risk for RSV LRTD 7578 |
| Abrysvo (RSV vaccine; bivalent stabilized prefusion F subunit) | Pfizer; BLA 125769/125768 | Aug 21, 2023 14 | Pregnant individuals at 32 through 36 weeks gestational age (to protect infants birth–6 months); individuals 60 years and older; individuals 18 through 59 years at increased risk 667068 |
| mRESVIA (RSV vaccine, mRNA) | ModernaTX; BLA 125796 | June 25, 2024 9 | Individuals 60 years and older; individuals 18 through 59 years at increased risk for RSV LRTD 5859 |
Arexvy (GSK)
Arexvy was licensed on the basis of a recombinant, adjuvanted RSV prefusion F antigen for the prevention of LRTD caused by RSV-A and RSV-B subtypes in adults 60 years of age and older 3336. The current prescribing information (label effective April 2026) states the indication as active immunization for the prevention of LRTD caused by RSV in individuals 60 years of age and older and in individuals 18 through 59 years of age who are at increased risk for LRTD caused by RSV 7578. The label carries a limitation of use that Arexvy is not for use in pregnant individuals 78.
The expansion below age 60 rests on additional clinical studies: Study 4 enrolled individuals 50 through 59 years of age with chronic medical conditions (chronic pulmonary disease, chronic cardiovascular disease, diabetes, chronic kidney or liver disease) associated with increased RSV risk, benchmarked against adults 60 and older, and Study 7 enrolled individuals 18 through 49 years of age with similar qualifying conditions (extended to include neurologic or neuromuscular disease) 7679. Immunogenicity in these younger at-risk cohorts was compared against the 60-and-older population using a non-inferiority framework rather than a new efficacy endpoint 79.
Abrysvo (Pfizer)
Abrysvo is the only RSV product with two mechanistically different indicated uses. Its maternal indication is active immunization of pregnant individuals at 32 through 36 weeks gestational age for the prevention of LRTD and severe LRTD caused by RSV in infants from birth through 6 months of age 166. This was the indication reviewed at the May 18, 2023 VRBPAC meeting, where the committee weighed the demonstrated vaccine efficacy against safety signals, particularly the imbalance in preterm birth 23. The label notes that Abrysvo has not been studied in pregnant individuals below 24 weeks gestational age or those at increased risk for preterm birth 72.
Separately, Abrysvo is indicated for active immunization for the prevention of LRTD caused by RSV in individuals 60 years of age and older, and in individuals 18 through 59 years of age at increased risk for LRTD caused by RSV 7068. The current label (effective December 2025) and the packaging both carry all three populations: pregnant individuals at 32–36 weeks, adults 60 and older, and adults 18–59 at increased risk 667071.
mRESVIA (Moderna)
mRESVIA is an mRNA-based RSV vaccine encoding the stabilized prefusion F glycoprotein, formulated as an RNA-lipid complex 9. It was approved June 25, 2024 for active immunization for the prevention of LRTD caused by RSV in individuals 60 years of age and older; the current label (effective June 2025) extends the indication to individuals 18 through 59 years of age at increased risk for LRTD caused by RSV 5859. In the pivotal older-adult study, vaccine efficacy against a first episode of RSV-LRTD (with two or more signs/symptoms) was 62.5% overall in participants 60 and older, with subgroup point estimates of 58.8% (60–69 years) and 78.0% (70–79 years); the 80-and-older subgroup was small (11 total cases) and not informative 60. The younger at-risk expansion was supported by immunogenicity non-inferiority (neutralizing antibody GMTs in adults 18–59 at increased risk versus adults 60 and older), not a separate efficacy trial 64.
RSV monoclonal antibodies (passive immunization)
The three monoclonal antibodies are all RSV F protein-directed agents given to infants and young children; none is a vaccine and each provides passive, single-season protection. They span nearly three decades of labeling, from the 1998 approval of palivizumab (restricted to defined high-risk pediatric groups) to the 2023 and 2025 approvals of nirsevimab and clesrovimab (broad infant populations).
| Product (generic) | Sponsor / BLA | Initial U.S. approval | Indicated pediatric population |
|---|---|---|---|
| Synagis (palivizumab) | Sobi / Swedish Orphan Biovitrum; BLA 103770 | 1998 45 | High-risk pediatric patients: premature birth (≤35 weeks GA) and ≤6 months at start of season; BPD requiring treatment within prior 6 months and ≤24 months; hemodynamically significant CHD and ≤24 months 4582 |
| Beyfortus (nirsevimab-alip) | Sanofi / AstraZeneca; BLA 761328 | 2023 48 | Neonates and infants born during or entering their first RSV season; children up to 24 months who remain vulnerable to severe RSV disease through their second season 4849 |
| Enflonsia (clesrovimab-cfor) | Merck Sharp & Dohme; BLA 761432 | 2025 23 | Neonates and infants born during or entering their first RSV season 23 |
Synagis (palivizumab)
Palivizumab, first approved in 1998, is a humanized IgG1κ monoclonal antibody directed at antigenic site A of the RSV F protein 44. It is indicated for the prevention of serious LRTD caused by RSV in three narrowly defined high-risk pediatric groups: patients with a history of premature birth (≤35 weeks gestational age) who are 6 months of age or younger at the beginning of RSV season; patients with bronchopulmonary dysplasia (BPD) that required medical treatment within the previous 6 months and who are 24 months of age or younger at the beginning of RSV season; and patients with hemodynamically significant congenital heart disease (CHD) who are 24 months of age or younger at the beginning of RSV season 4582. Unlike the two newer antibodies, Synagis is not indicated for the general infant population and is dosed monthly across the RSV season rather than as a single dose.
Beyfortus (nirsevimab)
Nirsevimab is an RSV F protein-directed fusion inhibitor with extended half-life, approved in 2023 48. It is indicated for the prevention of RSV LRTD in two populations: neonates and infants born during or entering their first RSV season, and children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season 4849. For the first season, dosing begins from birth for infants born during the season, or once before the season for those born outside it, reflecting roughly 5 months of protection from a single dose 49. The second-season (up-to-24-months) population maps to children with conditions such as chronic lung disease of prematurity or hemodynamically significant CHD, studied in trials that used palivizumab as an active comparator 52. The label states it is not known whether Beyfortus is safe and effective in children older than 24 months 50.
Enflonsia (clesrovimab)
Clesrovimab, approved in 2025, is the most recent RSV monoclonal antibody and also an RSV F protein-directed fusion inhibitor 23. Its indication is narrower than nirsevimab's: prevention of RSV LRTD in neonates and infants who are born during or entering their first RSV season 23. The label notes it is not known whether Enflonsia is safe and effective in children older than 12 months of age, and there is no second-season (up-to-24-months) population in the indication 26. Its clinical program included a pivotal trial in neonates and infants ≥29 weeks GA entering their first season (Trial 004) and a trial in infants born ≥35 weeks GA and infants with chronic lung disease of prematurity or hemodynamically significant CHD, with palivizumab as comparator in the latter 2324.
How the pieces fit together
Two structural points are worth holding in view. First, infant protection is delivered by two different regulatory routes: directly, through the monoclonal antibodies given to the child (Synagis, Beyfortus, Enflonsia), and indirectly, through Abrysvo given to the pregnant individual at 32–36 weeks to protect the infant from birth through 6 months 66. The vaccines Arexvy and mRESVIA have no infant indication at all and, in Arexvy's case, an explicit limitation against use in pregnancy 78.
Second, the older-adult vaccine indications have converged on a common structure: a core indication for adults 60 and older, plus an expansion to adults 18–59 at increased risk that was supported by immunogenicity bridging rather than fresh efficacy trials 7964. On the antibody side, the labeling has broadened over time, from palivizumab's three defined high-risk groups (1998) to nirsevimab's general first-season plus vulnerable second-season populations (2023), while clesrovimab (2025) is licensed only for the first season 454823. A reader comparing products for a specific population, dosing schedule, or efficacy endpoint would find those details in the individual clinical-studies sections, and can ask Rhizome to pull the head-to-head trial data or the VRBPAC deliberations directly.