The application dimension of Vaccine Nasal Spray segmentation differentiates products by the disease target, directly influencing revenue streams and R&D allocation. Influenza remains the dominant application, accounting for roughly 45 % of global sales, driven by seasonal demand cycles, established immunization programs, and a mature regulatory pathway. COVID‑19 nasal vaccines, representing about 30 % of the market, have surged due to pandemic‑related funding, accelerated approvals, and heightened public awareness of mucosal immunity. Respiratory syncytial virus (RSV) occupies an emerging niche with an estimated 15 % share, as pediatric and elderly cohorts drive adoption of needle‑free delivery for a virus lacking a widely used vaccine. The residual 10 % labeled Other aggregates niche indications such as adenovirus, parainfluenza, and experimental platforms, reflecting exploratory pipelines and regional health priorities. Collectively, these application segments shape the overall market size by dictating manufacturing scale, pricing dynamics, and geographic penetration, making precise delineation essential for strategic forecasting.