Title: Recombinant Plague Vaccine rF1V in Healthy Volunteers

This Phase 2(a) clinical trial is designed as a dose-blinded, block-randomized, multi-center study to select a dosage and schedule of rF1V vaccine for further studies based on the immune response up to Day 210. Additional immunogenicity and safety/reactogenicity data will be collected through Day 540. Selection of dosage and schedule will be based on GMCs and seroconversion rates for anti-F1, anti-V and anti-rF1V antibody titers. Approximately 400 healthy adult volunteers will be enrolled (100 per group) in this study.