Limited benefit of post-exposure prophylaxis with VSV-EBOV in Ebola virus-infected rhesus macaques.

VSV-EBOV has been successfully used in ring vaccination approaches during Ebola virus (EBOV) disease outbreaks demonstrating its general benefit in short-term prophylactic vaccination, but actual proof of its benefit in true post-exposure prophylaxis (PEP) for humans is missing. Animal studies have indicated PEP efficacy when VSV-EBOV was used within hours of lethal EBOV challenge. Here, we used a lower EBOV challenge dose and a combined intravenous and intramuscular VSV-EBOV administration to improve PEP efficacy in the rhesus macaque model. VSV-EBOV treatment 1 hour post EBOV challenge resulted in delayed disease progression but little benefit in outcome. Thus, we could not confirm previous results indicating questionable benefit of VSV-EBOV for EBOV PEP even in a nonhuman primate model.