This is single site, randomized, blinded comparison of the immunogenicity, of Imovax (RVi) and Rabavert (RVa) rabies vaccines when subjects are administered rabies immune globulin (RIG) or SYN023. Subjects will be randomized into one of four dose groups: RVi + SYN023, RVi+RIG, RVa+SYN023 and RVa+RIG. The initial dose of RVi and RVa will be co-administered with either RIG or SYN023). Rabies virus neutralizing activity (RVNA) and blood levels of SYN023 will be measured for the remainder of the trial while the rest of the five RVi and RVa doses are given. The study will last 112 days. SYN023 concentrations and anti-SYN023 antibodies will also be measured.