Freeze-Dried MVA-BN® Lot Consistency Smallpox Trial

This is a Phase 3 multicenter trial to evaluate safety and immune response of three consecutive production lots of freeze-dried (FD) MVA-BN smallpox vaccine. The vaccine will be given to healthy subjects who do not have a smallpox scar. Approximately 1110 subjects will be randomly enrolled into one of three groups: Group 1 will include 370 subjects, who will receive two separate injections (shot) with a short needle, given below the skin of the upper arm with 0.5 mL FD MVA-BN (Lot 1). Group 2 will include 370 subjects, who will receive two separate injections (shot) with a short needle, given below the skin of the upper arm with 0.5 mL FD MVA-BN (Lot 2). Group 3 will include 370 subjects, who will receive two separate injections (shot) with a short needle, given below the skin of the upper arm with 0.5 mL FD MVA-BN (Lot 3). The primary objective of the trial is to show that the immune response elicited (produced) by three consecutively produced MVA-BN lots are statistically (numerically) comparable.