Detectable Vesicular Stomatitis Virus (VSV)–Specific Humoral and Cellular Immune Responses Following VSV–Ebola Virus Vaccination in Humans

This study investigates preexisting and vaccine-induced vector immunity in 30 participants of a Phase-1 VSV-EBOV Ebola vaccine trial. No preexisting immunity was detected, however humoral and cell-mediated immunity against internal VSV proteins was observed in up to 36% of vaccines. Abstract In response to the Ebola virus (EBOV) crisis of 2013–2016, a recombinant vesicular stomatitis virus (VSV)–based EBOV vaccine was clinically tested (NCT02283099). A single-dose regimen of VSV-EBOV revealed a safe and immunogenic profile and demonstrated clinical efficacy. While EBOV-specific immune responses to this candidate vaccine have previously been investigated, limited human data on immunity to the VSV vector are available. Within the scope of a phase 1 study, we performed a comprehensive longitudinal analysis of adaptive immune responses to internal VSV proteins following VSV-EBOV immunization. While no preexisting immunity to the vector was observed, more than one-third of subjects developed VSV-specific cytotoxic T-lymphocyte responses and antibodies.