Researchers at Washington University in St. Louis reported an intranasal adenoviral‑vectored H5N1 vaccine that produced robust mucosal and systemic immunity and prevented H5N1 infection in mice and hamsters, according to a Cell Reports Medicine publication. The team tested the candidate in animals with and without prior seasonal influenza exposure and found protection irrespective of antigenic history. Lead author Michael S. Diamond and colleagues emphasize delivery to the upper airway to block infection and transmission. Intranasal vaccination targets mucosal immunity — antibodies and cells at the infection site — which can be critical for respiratory pathogens and for curbing onward spread.