Immunogenicity of a Recombinant MVA Vector Vaccine Expressing the Prefusion RSV F Protein in Balb/c Mice.

Background: Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections and poses a substantial disease burden to infants, older adults, and immunocompromised populations. Methods: In this study, a recombinant vaccinia virus (rMVA-RSV preF) was constructed based on the modified vaccinia virus Ankara (MVA) platform by inserting a stabilized prefusion F protein gene of RSV into the MVA genome. The immunogenicity of rMVA-RSV preF and preF protein was evaluated in Balb/c mice under different vaccination regimens. Results: A heterologous prime-boost regimen, priming with rMVA-RSV preF and boosting with AS01E-adjuvanted preF protein, elicited robust cellular and humoral immune responses with a Th1 bias. This regimen significantly enhanced immunogenicity compared to homologous vaccination. Conclusions: There is a lack of data from further challenge studies to support the efficacy of the rMVA-RSV preF vaccine in terms of protection, but our findings demonstrate a favorable immunogenicity profile of the rMVA-RSV preF vaccine, supporting its further development as a promising RSV vaccine candidate.