Washington University School of Medicine reported an intranasal adenoviral‑vectored H5N1 vaccine that protected hamsters and mice from highly pathogenic avian influenza strains and remained effective in animals with prior seasonal influenza exposure. Researchers led by Michael S. Diamond published the preclinical results in Cell Reports Medicine and emphasized mucosal delivery to block infection at the respiratory gateway. The team tested antigen‑experienced and naive models and demonstrated prevention of viral replication in the nose and lungs, suggesting potential to reduce both disease and transmission. While the data are preclinical, the delivery platform and proof‑of‑concept against contemporary H5N1 variants position the candidate for accelerated translational work if safety and manufacturability benchmarks are met.