The Application dimension of the Viral Vector Vaccine for Humans market is divided into four primary categories: Infectious diseases, Oncology, Rare diseases, and Emerging pathogens. Infectious diseases dominate the market, accounting for roughly 55 % of total revenue, driven by large‑scale immunization programs against influenza, COVID‑19, and dengue. Oncology follows with an estimated 30 % share, reflecting the growing use of viral vectors to deliver tumor‑associated antigens and stimulate anti‑cancer immunity. Rare diseases contribute about 10 % of the market, where vector platforms enable targeted therapies for conditions such as hemophilia and spinal muscular atrophy, often supported by orphan‑drug incentives. Finally, Emerging pathogens represent a nascent but strategic segment (≈5 %), encompassing rapid‑response vaccine development for novel viruses like Zika or Marburg, where speed-to‑market is critical. Together, these application segments define the overall market size and shape investment priorities, illustrating the breadth of the Viral Vector Vaccine for Humans segmentation landscape.