Administered immunoglobulins directed against vaccine antigens have the potential to inhibit the immune response to a vaccine. Both vaccination and immune globulin are used together in the post exposure prophylaxis of rabies virus infection. SYN023 (a mixture of two monoclonal antibodies CTB011 and CTB012) may be used instead of human rabies immune globulin. Since there is a risk of antagonism of vaccine induced immunity by SYN023, as there is with rabies immune globulin, it is necessary to study possible interactions of these two agents that might be used concurrently. This is single site, randomized, blinded comparison of the immunogenicity, of Imovax (RVi) and Rabavert (RVa) rabies vaccines when administered concurrently with 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). The remaining 4 doses of RVi and RVa will be administered intramuscularly as specified in the product labeling. Serum rabies virus neutralizing activity (RVNA) and serum concentrations of the components of of SYN023 will be measured for the remainder of the trial while the rest of the five RVi and RVa doses are given. Adverse events will be collected for the duration of the trial. The study will last 112 days. Anti-SYN023 antibodies will also be measured.