The results of studies by researchers at Yale University have demonstrated how intranasal vaccination can provide broad-based protection against heterologous respiratory viruses in mice, while systemic immunization, which used an injection to elicit body-wide protection, does not. The studies, focused on protecting against influenza infection, demonstrated that intranasal, but not systemic immunization induced IgA secretion from antibody secreting cells (ASCs) in the lung mucosa, which protected against a secondary challenge with either the same, or a different strain of the flu virus.
