Respiratory Syncytial Virus (RSV) Vaccines 2025
The World Health Organization (WHO) continues to prioritize the development of safe and effective vaccines against the respiratory syncytial virus. Since the 1960s, researchers have studied RSV vaccine candidates. Over many years, various strategies have been pursued to develop an effective and safe RSV vaccine, including inactivated virus preparations, live attenuated or ated/genetically engineered viruses, purified RSV protein subunit vaccine preparations, vector-based vaccine candidates, and DNA-based vaccines.
As of August 2025, the U.S. Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), Canada, Japan, the UK's Medicines and Healthcare products Regulatory Agency (MHRA), Germany, and the European Commission (EC) recommend certain adults and pregnant women receive a single dose of an approved RSV vaccine based on specific conditions. On June 25, 2025, the CDC's Advisory Committee on Immunization Practices met and reviewed Maternal/Pediatric RSV immunization options.
On December 12, 2024, the FDA's Vaccines and Related Biological Products Advisory Committee reviewed various presentations on the effectiveness of RSV in pediatrics. On June 26, 2024, the CDC's Advisory Committee on Immunization Practices (ACIP) recommended that most adults aged 60 and older receive an RSV vaccination. For the 2024-2025 respiratory virus season, the CDC recommends that everyone ages 75 and older receive the RSV vaccine an,d people ages 60–74 who are at increased risk of severe RSV, meaning they have certain chronic medical conditions, such as lung or heart disease, or they live in nursing homes, receive the RSV vaccine. As of September 2024, approximately 34% of seniors (aged 75 and above) had received an RSV vaccination.
RSV Vaccines Approved in the U.S.
AREXVY™ RSV vaccine is approved for adults. AREXVY became available in U.S. pharmacies on August 17, 2023.
ABRYSVO™ RSVpreF, an RSV bivalent vaccine from Pfizer Inc., received approval from the US FDA and European Commission for older adults and pregnant women in 2023.
mRESVIA® mRNA-1345 is a vaccine against RSV developed by ModernaTX, Inc. It is approved for use in the United States and is recommended in Europe.
RSV Vaccination Risk of Guillain-Barré Syndrome
On January 7, 2025, the FDA required and approved safety labeling changes to the Prescribing Information for Abrysvo and Arexvy. Each manufacturer must now include a new warning about the risk of Guillain-Barré syndrome (GBS), a rare neurological disorder in which the immune system mistakenly attacks part of the peripheral nervous system. The FDA noted that the benefits of vaccination with Abrysvo and Arexvy still outweigh the risk. A U.S. CDC MMWR confirmed on May 30, 2024, that GBS was identified as a potential safety concern (Abrysvo 4.4 per million) in clinical trials. On February 29, 2024, the ACIP meeting reviewed the efficacy of the RSV vaccine and discussed GBS Risk Analysis, benefits and risks, as well as ACIP Work Group interpretations and debate.
RSV Vaccination Rate USA
According to the US CDC's RSVVaxView, the overall RSV vaccination rate among pregnant women was about 17.8% as of 2024. As of May 22, 2024, 24.4% of adults 60 years and older were estimated to have received an RSV vaccine. Across the U.S., receipt of an RSV vaccine was lowest in Mississippi, 14.2%, and highest in Colorado, 32.2%.
RSV Vaccine Effectiveness
The JAMA Network published a Research Letter on September 4, 2024, concluding VE against RSV-associated hospitalization was 75% (95% confidence interval: 67% to 87%).
RSV Vaccine Candidates 2025
In early 2025, the RSV immunization development landscape remained active. Thirty candidates were in clinical development using protein-based, live-attenuated, chimeric vectors and mRNA approaches. Various pharmaceutical companies are conducting phase 3 clinical trials on RSV vaccine candidates.
Clover Biopharmaceuticals, Ltd. announced on March 24, 2025, IND clearance by the U.S. FDA and that enrollment of the first participants has been completed in a Phase I revaccination clinical trial evaluating SCB-1019, a non-adjuvanted bivalent RSV prefusion-stabilized F (PreF)-Trimer subunit vaccine candidate based on Clover's Trimer-Tag vaccine technology platform.
Vaxxas utilizes a next-generation vaccine antigen (DS2) developed by NIH scientists to elicit a more robust and durable immune response against RSV compared to the antigen used in globally approved vaccines (DS-Cav1). Vaxxas' proprietary HD-MAP offers the potential for needle-free vaccination.
CSPC Pharmaceutical Group Limited's mRNA RSV vaccine candidate, SYS6016, is currently conducting clinical trials in China.
Icosavax/AstraZeneca's IVX-121, a vaccine candidate for RSV and hMPV, incorporates a stabilized prefusion F antigen licensed from the NIAID/NIH (DS-CAV1). VLP technology further enhances the response's magnitude, quality, and durability against the prefusion RSV F. Currently, there are no treatments or preventive therapies for hMPV, and no combination vaccines are available for RSV. In a Phase 1 trial, IVX-A12 induced robust immune responses against RSV and hMPV at Day 28 in older adults across various dosage levels, both with and without adjuvant. The ongoing Phase 2 clinical trial of IVX-A12 results include IVX-A12-induced geometric mean titers (GMTs) in RSV-A neutralizing antibody titers (nAbs) of approximately 12,200 IU/mL, compared to approximately 2,000 IU/mL for the placebo at Day 28. IVX-A12 induced GMTs in RSV-B nAbs of approximately 5,500 IU/mL compared to approximately 1,300 IU/mL for placebo at Day 28; IVX-A12 induced GMTs in hMPV-A nAbs of approximately 1,600 assay units/mL compared to approximately 400 assay units/mL for placebo at Day 28. IVX-A12 induced GMTs in hMPV-B nAbs of approximately 15,300 assay units/mL compared to approximately 6,700 assay units/mL for placebo at Day 28. No standardized international units exist in the field for hMPV.
Clover Biopharmaceuticals, Ltd. SCB-1019 is a bivalent RSV-A/RSV-B vaccine candidate based on the prefusion-stabilized F (PreF) protein. It leverages the validated Trimer-Tag platform and proprietary stabilizing PreF mutations. On June 18, 2024, Clover announced positive preliminary immunogenicity and safety data from its Phase 1 clinical trial evaluating SCB-1019 in the older adult and elderly cohort.
Codagenix Inc.'s CodaVax™-RSV is an intranasal, live-attenuated vaccine candidate for preventing RSV infection, which has received the US FDA Fast Track designation and has launched two Phase 1 studies. A pediatric Phase 1 study evaluating CodaVax has an age-de-escalation, dose-escalation design designed to assess safety and immunogenicity in the 6-month-to-5-year-old population.
Meissa Vaccines MV-012-968 is an investigational, live-attenuated vaccine that protects against RSV. Meissa's intranasal live attenuated MV-012-968 vaccine candidate elicits a systemic and solid mucosal IgA antibody response in RSV-naïve children. As of August 8, 2023, 100% of RSV-naïve infants and toddlers responded to two doses of 107 PFU of MV-012-968. Safety data indicate that MV-012-968 is well-tolerated and highly attenuated, with no serious adverse events related to the vaccine reported, no Grade 2 or 3 fever, and low levels of transient vaccine virus shedding detected at the highest doses.
ResVax is a vaccine candidate from Novavax composed of recombinant RSV F nanoparticles adsorbed to aluminum phosphate. The F protein is essential to RSV infectivity and is the target of palivizumab.
DS-Cav1 was developed by VRC, NIAID, and is composed of the RSV fusion glycoprotein ectodomain assembled as a trimer stabilized in its prefusion native conformation with a foldon trimerization domain at the C-terminus and four internal mutations designated DS-Cav1 (4.1DHFR_RSVAF).
Ad26.RSV preF vaccine is a protein-based RSV vaccine candidate tested in adults produced by Pfizer, Inc.
EDP-938, Enanta's lead N-protein inhibitor, is being developed to treat RSV infection and was granted Fast Track Designation by the US FDA.
Icosavax Inc. IVX-A12 is a bivalent (RSV/hMPV) formulation, incorporating single and multiple hMPV dosage levels in older adults 60 and above. The FDA granted Fast Track designation for IVX-A12 on February 21, 2023.
Artificial Cell Technologies, Inc. developed a fully synthetic microparticle RSV vaccine candidate.
Calder Biosciences will evaluate DT-preF, its lead RSV vaccine candidate.
RSV/6120/ΔNS2/1030s is a live-attenuated intranasal RSV vaccine candidate containing a deletion of the interferon antagonist NS2 gene and a genetically stabilized temperature-sensitivity mutation in the polymerase gene. It was infectious and induced primary neutralizing serum antibody responses and potent memory antibody responses, n6-- to 24-month-old RSV-seronegative children, but it may be associated with rhinorrhea.
Immorna Biotherapeutics Inc. JCXH-108 is a monovalent RSV vaccine developed using the company's proprietary mRNA and RTU-LNP technologies.
Vicebio Ltd. initiated a Phase I clinical trial with VXB-241, its bivalent vaccine targeting RSV and hMPV. Initial clinical readouts from the Phase 1 study are expected to be released in mid-2025.
AIM Vaccine Co., Ltd. developed an mRNA RSV vaccine.
RSV Vaccines in China
RSV therapeutic candidates are in mainland China, Hong Kong, Macau, and Singapore. Sisunatovir is being evaluated for potentially treating RSV infection in pediatric and adult patients. Pfizer Inc. and LianBio announced on December 19, 2022, that Pfizer opted to develop and commercialize sisunatovir (RV521). The US FDA granted Sisunatovir Fast Track Designation. Additionally, it is being evaluated in a Phase 2 clinical study in children. On November 14, 2022, Nuance Pharma announced that China's Center for Drug Evaluation had approved its application, supporting the pivotal Phase III MVA-BN RSV vaccine clinical trial.
RSV Vaccine Coadministration With Influenza Vaccine
According to the US CDC, the available data on the immunogenicity of coadministering RSV and other vaccines is currently limited. The US CDC presented the following coadministration information on September 19, 2023: There is currently limited data on the immunogenicity of coadministration of RSV and other vaccines. In general, the coadministration of RSV and seasonal influenza vaccines met noninferiority criteria for immunogenicity. However, RSV and influenza antibody titers were generally somewhat lower with coadministration; the clinical significance of this is unknown. Additional studies on the immunogenicity of coadministration of RSV with other adult vaccines are being conducted. A draft, revised vaccine schedule addendum was presented on September 22, 2023.
RSV Vaccination Timing
The CDC confirmed in January 2024 that most of the continental United States could administer the maternal RSV vaccine from September through January 31. However, in jurisdictions where seasonality differs from that of most of the continental United States, such as Alaska, southern Florida, Guam, Hawaii, Puerto Rico, the US-affiliated Pacific Islands, and the U.S. Virgin Islands, healthcare providers should follow state, local, or territorial guidance on the timing of administering the RSV vaccine (Pfizer Abrysvo) for pregnant women.
RSV Vaccine Price
The global RSV Therapeutics Market Size is estimated to reach approximately $836 million by 2028, exhibiting a compound annual growth rate (CAGR) of 5.76%. Additional RSV vaccine and treatment price information is posted at InstantRx™.
RSV Vaccine Market Size USA
Data provider Airfinity indicates the U.S. market for RSV vaccines in elderly adults in 2023 totaled about $2.4 billion. Affinity expects 2024 revenues to decline slightly to $2.2 billion and forecasts RSV vaccine sales to be about $1.7 million annually by 2030.
RSV Monoclonal Antibody
As of January 2025, the US FDA approved RSV monoclonal antibody therapies for children. The WHO SAGE recommends that all countries introduce passive immunization to prevent severe RSV disease in young infants.
RSV Vaccination Pre-Term Births
WHO's SAGE reported in September 2024 that there were no serious adverse events in the vaccinated women. However, an excess in pre-term births was observed in the vaccine group. This non-statistically significant imbalance was observed in trial sites in two upper-middle-income countries but not in other settings. To mitigate the potential risk of pre-term births, SAGE considered narrowing the gestational age for maternal RSV vaccination. For countries deciding to use the maternal vaccine to prevent severe RSV disease in infants, SAGE recommends a single dose of vaccine in the third trimester of pregnancy.
