Xiamen University Presents Novel mRNA RSV Vaccine Candidate with Potential to Fill Pediatric Market Gap

U.S. Food and Drug Administration (The FDA has approved RSV vaccines developed by GSK, Pfizer, and Moderna to protect high-risk populations from respiratory syncytial virus (RSV). These vaccines all utilize the prefusion F (pre-F) protein as the immunogen and are approved for use in elderly populations.

Besides,Pfizer's RSV vaccine has also been approved for use in pregnant women, an additional indication that has enabled Pfizer to outperform GSK in the product’s market performance: The burden of RSV disease is particularly heavy among infants and young children, especially preterm infants, leading countries such as England to preferentially procure Pfizer's RSV vaccine for maternal immunization.

At the same time, the new RSV monoclonal antibody (Nirsevimab) for newborns, jointly developed by Sanofi and AstraZeneca, has become a strong driving force for the growth of Sanofi's new product business in the past year.

Despite these roundabout solutions, the pediatric market for RSV vaccines remains空白. Recently, aClinical trials of Moderna's mRNA vaccine for infants show an imbalance in severe RSV-related lower respiratory tract infections between the vaccinated group and the placebo group among infants not previously exposed to RSV, leading to a study pause and raising concerns about VERD (vaccine-enhanced respiratory disease) risk.)质疑和担忧。

On February 5, Nature Communications published a study by Professor Ning-Shao Xia's team from Xiamen University.Self-developedPreclinical Research Results of mRNA RSV Vaccine: Vaccine Testing Aims to Provide Targeted Protection for High-Risk Populations Such as Children and the Elderly.

The vaccine is based onRSV Pre-F proteinDevelopment, is a useLC2DM-Lipid Nanoparticles (LC2DM-LNP) ModificationThemRNA Vaccine. UniqueThe special feature is thatPre-F ProteinByTruncateAnd anchorOn the cell membrane, aiming to eliminate non-neutralizing epitopes and enhance immunogenicity.The vaccine is delivered via lipid nanoparticles (LNP) delivers mRNA, ensuring prolonged antigen expression at the immunization site. The results show:

Immune Response:In Youth and Old AgeIn BALB/c mice, the LC2DM-LNP vaccine elicited high titers of neutralizing antibodies (nAb) and induced a Th1-biased T-cell immune response. In the mouse model, the LC2DM-LNP vaccine provided complete protection against RSV without signs of VERD.

Antibody Quality:The antibody quality induced by LC2DM-LNP vaccine is higher, with a higher ratio of neutralizing antibodies to binding antibodies, indicating its potential to avoid the possible VERD effect. By removing the stem region of the pre-F protein, the immune competition of non-neutralizing epitopes is reduced, further improving the antibody quality.

Maternal Immunity:In the maternal immune model, vaccinationLC2DM-LNP dams transfer high levels of pre-F-specific antibodies to their offspring, maintaining high nAb titers for up to 4 weeks post-birth. Offspring exhibit significant protection during RSV challenge, with markedly reduced lung viral loads and pathology scores.

Safety:LC2DM-LNP Vaccine Did Not Trigger VERD in Multiple Animal Models, Demonstrating Good Safety. Even in Cases of Breakthrough Infection, Animals Vaccinated with LC2DM-LNP Did Not Exhibit Enhanced Pulmonary Inflammation.

Despite some limitations of the study, such as the lack ofFI-RSV Control Group, Limiting the Ability to Assess VERD Risk. Maternal immunization studies in cotton rats pregnant without RSV exposure may not fully reflect the exposure history of human populations.

But all in all, the evidence from the study of this candidate vaccine has demonstrated its potential for application among high-risk populations such as the elderly, pregnant women, and young children. In addition, Xiamen University may also be simultaneously developing improved RSV monoclonal antibodies.

Last yearIn November, Nature Communications also published the preclinical research results of another preventive product, RSV monoclonal antibody, developed by Professor Ning-Shao Xia's team. The study showed that, compared with the use of palivizumab (Palivizumab,(Approved in the U.S. in 1998)Compared with the mouse precursor, the neutralizing efficacy of the candidate monoclonal antibody product has increased by approximately20 times, and the neutralizing efficacy is approximately 3 times higher compared to nirsevimab (Nirsevimab, approved in China in 2023).

In 2013, Professor Xia Ningxiao's team participated in the RSV-specific antibody research project at the Vaccine Research Center of the National Institute of Allergy and Infectious Diseases under the U.S. National Institutes of Health (the collaborative research findings were published in Science).ResearchNot only promoted abroadThe R&D progress of RSV vaccines and monoclonal antibodies may also simultaneously provide Xiamen University with opportunities for independent research and development andImproved RSV Vaccine AntigenAnd the opportunity of monoclonal antibodies.

Lin M, Yin Y, Zhao X, et al. A truncated pre-F protein mRNA vaccine elicits an enhanced immune response and protection against respiratory syncytial virus. Nat Commun. 2025 Feb 5;16(1):1386. doi: 10.1038/s41467-025-56302-1. 

McLellan JS, Chen M, Leung S, et al. Structure of RSV fusion glycoprotein trimer bound to a prefusion-specific neutralizing antibody. Science. 2013 May 31;340(6136):1113-7. doi: 10.1126/science.1234914. 

Sun Y, Liu L, Qiang H, et al. A potent broad-spectrum neutralizing antibody targeting a conserved region of the prefusion RSV F protein. Nat Commun. 2024 Nov 21;15(1):10085. doi: 10.1038/s41467-024-54384-x. 

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