Rift Valley fever vaccine--antibody and immune response in cattle to a live and an inactivated vaccine.

In a study of the response in cattle to a live and an inactivated Rift Valley fever (RVF) vaccine prepared from cell cultures infected with RVF virus, the effects of varying doses and combinations of these vaccines were compared. The antibody response to a primary injection of either vaccines was poor when measured by the serum virus neutralization test (SVN) and the haemagglutination-inhibition test (HI) but a booster dose of inactivated vaccine evoked a good anamnestic response in cattle previously injected with either of these vaccines. Cattle vaccinated with the live vaccine but negative to the SVN or the HI for RVF were immune when challenged with a virulent RVF virus isolated from a cow during 1974.