- A single-dose of a new intranasal spray COVID-19 vaccine (live-attenuated virus vector-based) is protective against symptomatic SARS-CoV-2 Omicron infections as a primary immunization for individuals without prior exposure. https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(23)00551-5/fulltext 5 comments science