 This study, as a post-marketing commitment to the Food and Drug Administration, is designed to detect the effect of raxibacumab on anthrax vaccine adsorbed AVA immunogenicity in a healthy volunteer population. This is a randomized, open-label, parallel group, two arm study to compare the immunogenicity of AVA at 4 weeks after the first AVA dose, when AVA is administered alone or concomitantly with raxibacumab. The study is planned to enroll approximately 30 to 534 subjects in up to 3 cohorts. The total duration of the study will be approximately 26 weeks. The dates reflect cohort 1. 