The VSV-based vaccine completely protects NHPs and additionally has proven successful in post-exposure treatment (reviewed in [255] ). A single immunization with recombinant VSV expressing MARV Musoke GP resulted in 100% protection of cynomolgus macaques challenged by intramuscular injection or aerosol exposure and protected against RAVV Ravn and MARV Angola [13, 256, 257] . Although MARV-specific IgG were produced, only low levels of neutralizing antibodies were detected [13, 257] . Surprisingly, T cell-mediated responses were not observed in NHPs vaccinated with recombinant VSV expressing MARV GP [13, 256] . Safety is a concern for this vaccine, especially for immunocompromised individuals, as it is a replication-competent VSV vector. However, in all VSV-based filovirus vaccine studies VSV viremia was observed only shortly after immunization. Additionally, the VSV-based filovirus GP vaccine was well tolerated and protective in immunocompromised mice and NHPs and lacked neurovirulence in NHPs [258] [259] [260] (reviewed in [255] ).