 This single-center, double-blind, randomized placebo-controlled phase 1 dose-finding study will have two randomization schemes. Volunteers who could later be exposed to Ebolavirus while working in epidemic areas deployable subjects will be randomized to receive one of two vaccine doses. Non-deployable volunteers, with no identified risk of Ebola exposure in the near term, will be allocated to one of three groups and receive the lower or higher vaccine dose, or a placebo. A single immunization will be performed. All subjects will be observed in the clinical trials unit CTU for 1.5 hours after vaccineplacebo injection. Subjects will complete post-injection diaries for 7 days after injection, as well as post-injection follow-up visits see below. On-site visits at the CTU will occur on days -90 to -1, 0, 1, 3, 7, 14, 28, 84, 168. Some subjects with a positive serologic response at 24 weeks may be requested to return for immune durability testing at 12 months. 