Respiratory Syncytial Virus (RSV) Vaccines 2024
The World Health Organization (WHO) continues to prioritize the development of safe and effective respiratory syncytial virus (RSV) vaccines. 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/genetically engineered viruses, purified RSV protein subunit vaccine preparations, vector-based vaccine candidates, and DNA-based vaccines.
As of December 2024, 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 December 12, 2024, the FDA's Vaccines and Related Biological Products Advisory Committee reviewed various RSV effectiveness presentations on pediatrics. On June 26, 2024, the CDC's ACIP committee recommended that most older people receive an RSV vaccination. For the 2024-2025 respiratory virus season, the CDC recommends that everyone ages 75 and older receive the RSV vaccine and 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, about 34% of seniors (75+) 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 U.S. 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 U.S. and recommended in Europe.
RSV Vaccination Rate USA
According to the U.S. 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 (50% to 87%).
RSV Vaccine Candidates 2024
In late 2024, the RSV immunization landscape remained active. Thirty candidates were in clinical development using protein-based, live-attenuated, chimeric vector, and mRNA approaches. Various pharmaceutical companies are conducting phase 3 clinical trials on RSV vaccine candidates.
Vaxxas uses a next-generation vaccine antigen (DS2) from NIH's scientists to prompt a more robust and durable immune response against RSV than the antigen used in globally approved vaccines (DS-Cav1). Vaxxas' proprietary HD-MAP offers the potential for needle-free vaccination.
CSPC Pharmaceutical Group Limited mRNA RSV vaccine candidate SYS6016 is conducting clinical trials in China.
Icosavax / AstraZeneca's IVX-121, an RSV and hMPV vaccine candidate, incorporates a stabilized prefusion F antigen licensed from NIAID/NIH (DS-CAV1). VLP technology further enhances the response's magnitude, quality, and durability to the prefusion RSV F. There are currently no treatments or preventative therapies for hMPV and no combination vaccines for RSV. In a Phase 1 trial, IVX-A12 induced robust immune responses against RSV and hMPV at Day 28 in older adults across dosage levels and 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 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 in the older adult and elderly cohort from its Phase clinical trial evaluating SCB-1019.
Codagenix Inc. CodaVax™-RSV is an intranasal, live-attenuated vaccine candidate for preventing RSV infection that received U.S. 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 specifically assessing safety and immunogenicity in the 6-month-to-5-year-old population.
Meissa Vaccines MV-012-968 is an investigational, live attenuated vaccine protecting against RSV. Meissa's intranasal live attenuated MV-012-968 vaccine candidate induces systemic 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 show that MV-012-968 is well-tolerated and highly attenuated, with no related serious adverse events, no Grade 2 or 3 fever reported, 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 on 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 U.S. 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, in a Phase I clinical trial with an efficacy readout. Preclinical studies are designed to assess the toxicity and tolerability of the lead candidate vaccine. The preclinical study will begin in November 2023, and the Phase 1 clinical study will start in H1 2024.
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 in 6-- 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 of the Phase 1 study are expected to launch in mid-2025.
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 U.S. FDA granted Sisunatovir Fast Track Designation in 2020. In addition, it is being considered in a global phase 2 clinical study in children. On November 14, 2022, Nuance Pharma announced China's Center for Drug Evaluation approved its application supporting its pivotal phase IIMVA-BN RSV vaccine clinical trial.
RSV Vaccine Coadministration With Influenza Vaccine
According to the U.S. CDC, the available data on the immunogenicity of the coadministration of RSV and other vaccines is currently limited. The U.S. 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 Administration Errors
As of January 17, 2024. a Clinician Outreach and Communication Activity (COCA Now) email confirmed that the number of RSV vaccination error reports received by the U.S. HHS's VAERS in young children under two years of age was 25 and 128 by pregnant women.
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 US 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 about $836 million by 2028, exhibiting a CAGR of 5.76%. Additional RSV vaccine and treatment price information are 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 Season 2024
The U.S. CDC, ECDC, and WHO report seasonal trends in RSV cases.
RSV Monoclonal Antibody
As of 2024, the U.S. 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 Guillain-Barré Syndrome (GBS) Analysis
On February 29. 2024, the U.S. CDC Advisory Committee on Immunization Practices (ACIP) meeting reviewed RSV vaccine efficacy and identified Guillain-Barré Syndrome (GBS) Risk Analysis, benefits and risks discussion, and ACIP Work Group interpretations and debate.
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.
