Anti-vector immunity following vaccination with Venezuelan equine encephalitis replicon filovirus vaccine

Abstract The Venezuelan equine encephalitis replicon (VRP) is the lead candidate for development as the DoD filovirus vaccine platform. One concern regarding this vaccine candidate focuses on the need to vaccinate individuals that have been pre-exposed to the VRP through previous vaccinations. To address this concern, cohorts of nonhuman primates (NHPs) were vaccinated with VRP expressing alphavirus proteins and VRP expressing Ebola virus Zaire (EBOV) glycoprotein either concurrently or sequentially. These NHPs were challenged with either 1000pfu of EBOV or 10^8 pfu of Venezuelan equine encephalitis virus (VEEV). Animals that were vaccinated with both vaccinations independent of sequence or co-administration were protected from each challenge. This data indicates that anti-vector immunity is not a concern with the VRP vaccine candidate as the product transitions into phase 1 clinical trials.