The NIH has initiated a Phase 1 trial for a novel nasal COVID-19 vaccine aimed at enhancing protection against emerging SARS-CoV-2 variants. This trial involves 60 adults who have received at least three doses of an mRNA vaccine. Participants will be observed over a year to assess the vaccine's safety and immune response, emphasizing mucosal immunity, potentially more effective against respiratory viruses. The MPV/S-2P vaccine uses a murine pneumonia virus vector for delivering the SARS-CoV-2 spike protein directly to respiratory tract cells, offering a targeted approach to infection and transmission prevention.