In a quest for bivalent mRNA vaccine for respiratory viruses: An effective strategy to overcome antigenic competition

In a world grappling with the evolving variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), another emerging respiratory virus, respiratory syncytial virus (RSV), continues to cause significant illness in millions of vulnerable people, including infants, elderly individuals, and immunocompromised people globally. 1 Cong B. Koç U. Bandeira T. Bassat Q. Bont L. Chakhunashvili G. Cohen C. Desnoyers C. Hammitt L.L. Heikkinen T. et al. Changes in the global hospitalisation burden of respiratory syncytial virus in young children during the COVID-19 pandemic: a systematic analysis. Lancet Infect. Dis. 2023; https://doi.org/10.1016/S1473-3099(23)00630-8 Abstract Full Text Full Text PDF PubMed Scopus (0) Google Scholar The situation is further complicated by the occurrence of co-infections with these viruses, which significantly worsens clinical outcomes and increases mortality rates in children. 2 Swets M.C. Russell C.D. Harrison E.M. Docherty A.B. Lone N. Girvan M. Hardwick H.E. Visser L.G. Openshaw P.J.M. et al. ISARIC4C InvestigatorsSARS-CoV-2 co-infection with influenza viruses, respiratory syncytial virus, or adenoviruses. Lancet. 2022; 399: 1463-1464https://doi.org/10.1016/S0140-6736(22)00383-X Abstract Full Text Full Text PDF PubMed Scopus (142) Google Scholar In a recent article published in Molecular Therapy, Wu et al. 3 Wu N. Zhang J. Shen Y. Zhang X. Zhou J. Wu Y. Li E. Meng X. Chuai X. Chiu S. Wang Y. A potential bivalent mRNA vaccine candidate protects against both RSV and SARS-CoV-2 infections. Mol. Ther. 2024; 32: 1-15https://doi.org/10.1016/j.ymthe.2024.02.011 Abstract Full Text Full Text PDF Scopus (0) Google Scholar describe the development of a bivalent mRNA vaccine encoding two prefusion stabilized forms of antigen (SARS-CoV-2 Omicron spike [S] and the RSV fusion [F] proteins) delivered with lipid nanoparticles (SF-LNPs). The examination of antigen expression and immune responses in monovalent versus bivalent vaccines, administered at equivalent doses, revealed that SF-LNPs provided robust protection against both RSV and SARS-CoV-2 Omicron infections in mouse and hamster models following immunization. Notably, the study uncovered a novel approach for addressing antigenic competition in bivalent vaccines culminating in the development of a vaccine capable of simultaneously safeguarding against two distinct infectious diseases. 3 Wu N. Zhang J. Shen Y. Zhang X. Zhou J. Wu Y. Li E. Meng X. Chuai X. Chiu S. Wang Y. A potential bivalent mRNA vaccine candidate protects against both RSV and SARS-CoV-2 infections. Mol. Ther. 2024; 32: 1-15https://doi.org/10.1016/j.ymthe.2024.02.011 Abstract Full Text Full Text PDF Scopus (0) Google Scholar