Washington University researchers reported an intranasal adenoviral‑vectored H5N1 vaccine that prevented infection in mice and hamsters in preclinical tests. Published in Cell Reports Medicine, the team led by Michael S. Diamond showed the vaccine generated strong mucosal and lung immunity and worked even in animals with prior seasonal‑flu exposure. The study names the platform as an approach to block upper‑airway infection and transmission. The paper details challenge studies where vaccinated rodents were protected from highly pathogenic H5N1 variants; authors highlight the vaccine’s efficacy despite potential interference from pre‑existing influenza immunity. This nasal delivery strategy targets mucosal immunity — local antibody and T‑cell responses in the airway — rather than systemic responses alone. The work positions intranasal vectored vaccines as a candidate for pandemic‑preparedness efforts and further translational testing.