The protection of ferrets against influenza by immunization with a split influenza vaccine.

Ferrets were vaccinated with either A/England/42/72 zonal purified influenza queous vaccine containing whole virus particles, or a subunit vaccine containing the purified hemagglutinin and neura-minidase proteins of A/England/42/72 adsorbed onto aluminium hydroxide. The immune status of the ferrets was assessed by reaction to challenge with virulent live virus of the homologous strain. In the preliminary experiment reported, the subunit vaccine conferred greater protection than the zonal purified vaccine.