According to an NIH release on February 3rd an investigational vaccine developed by Emergent Biosolutions has completed Phase-1 trials.  The vaccine termed Ad4-H5-VTN is an adenovirus- vectored recombinant vaccine stimulating antibodies to viral hemagglutinin.  The vaccine can be administered either intranasally or via a tonsillar swab.  Participants receiving vaccine by either of the two routes showed elevated H5-specific neutralizing antibody compared to a negligible response in a third group receiving the vaccine by the oral route. 

A positive H5-specific CD4+ and CD8+T-cell response was measured in vaccinates.  Serum-neutralizing antibodies were present 26 weeks after vaccination and persisted for three to five years after a single intranasal dose of vaccine.  The intranasal vaccine induced a mucosal antibody response in the nose, mouth and rectum.  Vaccinates shed viral DNA for two to four weeks, but virus could be cultured for only one day following vaccination.

The technology is obviously of direct application in humans based on the Phase-1 trial, but offers opportunities for mass immunization of poultry given a suitable vector virus.

Matzuda, K. et al A Replication Competent Adenovirus-Vectored Influenza Vaccine Induces Durable, Systemic, and Mucosal Immunity. Journal of Clinical Investigation. DOI:.org/10.1172/jci140794 (2020)