The filoviruses, Marburg virus (MARV) and Ebola virus, causes severe hemorrhagic
fever with high mortality in humans and nonhuman primates. A promising filovirus
vaccine under development is based on a recombinant
vesicular stomatitis virus (rVSV) that expresses individual filovirus
glycoproteins (GPs) in place of the VSV
glycoprotein (G). These
vaccines have shown 100% efficacy against
filovirus infection in nonhuman primates when challenge occurs 28-35 days after a single injection immunization. Here, we examined the ability of a rVSV MARV-GP
vaccine to provide protection when challenge occurs more than a year after vaccination. Cynomolgus macaques were immunized with rVSV-MARV-GP and challenged with MARV approximately 14 months after vaccination. Immunization resulted in the
vaccine cohort of six animals having anti-MARV GP
IgG throughout the pre-challenge period. Following MARV challenge none of the vaccinated animals showed any signs of clinical disease or
viremia and all were completely protected from MARV
infection. Two unvaccinated control animals exhibited signs consistent with MARV
infection and both succumbed. Importantly, these data are the first to show 100% protective efficacy against any high dose filovirus challenge beyond 8 weeks after final vaccination. These findings demonstrate the durability of VSV-based filovirus
vaccines.