Novel vaccine platforms for respiratory viruses: a review of licensed vaccines and candidates in late-stage development

INTRODUCTION: Respiratory infections with influenza, respiratory syncytial virus (RSV), and SARS-CoV-2 are a major cause of global mortality. Vaccination is a cornerstone of disease prevention, though traditional platforms face challenges. Recently, several vaccines utilizing mRNA and adenovirus platforms were brought to the market, with additional vaccines undergoing Phase 3 clinical testing. AREAS COVERED: This review assesses vaccine literature primarily from 2020 to the present, using National Library of Medicine databases. The rapidity of mRNA technology was tested and implemented successfully during the COVID-19 pandemic. Since then, the mRNA RSV vaccine has been licensed as well. mRNA platforms also offer the ability of combining antigens for multivalent vaccines against multiple pathogens. Several combination products have been used in phase III clinical trials. Adenovirus-vectored vaccines for respiratory viruses have the added advantage of mucosal-based delivery and inducing a potentially stronger local immune response. However, both of these platforms have immunogenicity and safety shortcomings. EXPERT OPINION: Novel respiratory virus vaccine platforms have demonstrated their importance with both endemic and pandemic pathogens, because of decades of concerted efforts and investment in research. Expediting future vaccine development requires a continuation of these efforts with a focus on pre-clinical models and a better understanding of correlates of protection.