Nasal-spray vaccine may protect against viruses, bacteria and allergens in mice

An experimental nasal-spray vaccine given to mice activated both innate and adaptive lung immunity and protected against several coronaviruses, two bacterial species and a house-dust-mite allergen for at least three months; the results are from animal tests and human trials are still required.

A new experimental nasal-spray vaccine stimulated broad lung immunity in mice and reduced illness from diverse respiratory challenges. The study, published Feb. 19 in Science, tested a formulation designed to mimic immune signals seen after BCG vaccination. Unlike typical vaccines that mainly target a single antigen, this approach primes innate immune cells while also recruiting adaptive responses. The vaccine, called GLA-3M-052-LS+OVA in the study, was given in three doses over three weeks and was evaluated in laboratory mice. Key findings: - Mice that received three doses showed protection for at least three months against SARS-CoV-2 and other coronaviruses, the bacteria Staphylococcus aureus and Acinetobacter baumannii, and an allergen derived from house dust mites. - The vaccine combines an adjuvant mix that mimics lung immune signals with a harmless egg-protein antigen to draw adaptive immune responses to the lungs. - Vaccinated animals experienced lower lung inflammation, less weight loss and lower risk of death after bacterial or viral exposure, and milder allergic reactions with reduced mucus after allergen exposure compared with unvaccinated mice. - Study authors emphasized that the results are from animal experiments and that further work is needed to evaluate safety and effectiveness in people. Summary: The research shows that a nasal-spray formulation can prime broad innate and adaptive immunity in the lungs of mice and reduce disease and allergic responses across multiple challenges. Human testing is required before conclusions about effects in people can be reached; timelines are undetermined at this time.