Influenza inflicts substantial burden of disease, but current vaccines have limited breadth of protection against strains and subtypes not in the vaccine. BPL-1357, a whole-virus, inactivated vaccine containing four wild-type, low-pathogenicity avian influenza viruses has demonstrated remarkable protection in animal models against a wide range of influenza viruses. In this phase I trial, forty-five healthy participants were randomized to receive BPL-1357 intramuscularly (IM), intranasally (IN), or placebo, in a prime and boost strategy, 28-days apart. The primary endpoints consisted of adverse events (AEs) and serious adverse events (SAEs) from enrollment through 28 days after the boost. The secondary endpoints were AEs and SAEs through 182 days after the boost and measurement of serum IgG and nasal IgA titers against hemagglutinin and neuraminidase vaccine antigens. Adverse effects were mostly mild and, other than mild injection-site pain more frequently observed in the IM group, occurred in a minority of patients. IM BPL-1357 induced higher serum IgG titers against H3, H5, and H7 relative to placebo, with 71.4%, 71.4%, and 85.7% of participants demonstrating a response. IM BPL-1357 vaccinated participants also experienced serum neutralizing and NA-specific responses, but no mucosal IgA responses against HA or NA. Subtle mucosal and serum responses were observed after IN vaccination, similar to preclinical experiments. These results suggest that BPL-1357 is well tolerated and immunogenic, particularly when given IM, but more work is needed to assess other dose levels, further characterize induced immunity, and evaluate efficacy against influenza infection and disease (NCT05027932).