Combating respiratory diseases with mucosal vaccines.

Mucosal vaccines hold many advantages over parenteral vaccines in the prevention of respiratory infections, which remain a major global health burden. Unlike parenteral vaccines, which primarily induce systemic immunity, mucosal vaccines stimulate robust local immune responses, including secretory IgA, tissue-resident memory T and B cells, and mucosal IgG. These responses collectively block viral entry, limit replication, and reduce transmission. Critically, they provide protection at the site of infection, offering rapid and durable immunity. This review highlights recent advances in mucosal vaccine platforms and delivery strategies for respiratory viruses, including emerging vaccine platforms, adjuvants, and heterologous prime-boost approaches, with a focus on findings from both animal models and human studies that define the key immune components and mechanisms of action in mucosal immunity. We further discuss evidence across major respiratory viruses and the translational and clinical implications for next-generation vaccine design. These insights underscore the role of mucosal vaccines in strengthening future pandemic preparedness.