Rift Valley Fever Virus Vaccine *

Abstract

Summary The procedure for the production of Rift Valley fever vaccine (RVF) has been described. Infectious vacuolating virus, SV 40, was present in 3 of 6 lots of inactivated RVF vaccine prepared from rhesus kidney cell cultures but was not detected in any of 5 sequential lots prepared in Cercopithecus cell cultures. Moreover, formalin-killed RVF virus vaccines derived from the African green monkey kidney cells are as immunogenic as those produced in rhesus cell cultures. The addition of 2% human serum albumin increases the heat stability of lyophilized RVF vaccine. The lyophilized vaccine is as antigenic as the fluid vaccine for the immunization of man when used either for the primary series or as a booster dose. The formalin-killed RVF vaccine prepared in monkey kidney cell cultures with the pantropic virus has protected exposed laboratory workers, thereby indicating the efficacy of the vaccine.