<qa>  What is the percentage of subjects at each dose level who develop a major cutaneous reaction?2. Determine the immunogenicity of three dose levels of ACAM1000 and a standard dose of Dryvax in healthy adults 18-29 years of age by comparing: athe proportion of subjects at each dose level who develop a major cutaneous reaction; bthe proportion of subjects in each treatment group who develop neutralizing antibodies, including the fold-increase in antibody titer between Baseline and Day 30 sera; and the geometric mean vaccinia neutralizing antibody titer on Day 30. 