Scientists have pioneered an influenza virus vector-based nasal spray vaccine platform and developed a nasal spray H5N1 avian influenza vaccine. During the early COVID-19 pandemic, this platform enabled the rapid development of a nasal spray vaccine in collaboration with mainland China’s Wantai BioPharm. After completing Phase 1-3 clinical trials, it was approved in 2022 as the world’s first nasal spray COVID-19 vaccine.