Field trials of ephemeral fever vaccines.

Various bovine ephemeral fever (BEF) vaccines were tested between 1982 and 1984 in 24 Queensland herds; neutralising antibody responses were monitored and six of the herds were closely observed following natural challenge with ephemeral fever. A vaccine regime of two consecutive vaccinations with attenuated virus combined with the adjuvant Quil A provided excellent protection against BEF for at least 12 months, whereas one vaccination with the Quil A vaccine or two vaccinations with vaccine containing the adjuvant aluminium hydroxide gel did not provide significant protection. Antibody responses were highest for the vaccine incorporating Quil A when it was given as two consecutive injections. There was an apparent relationship between neutralising antibody response and the level of protection.