This is a phase 2, randomized, active-controlled, double-blinded, multi-site study to assess the safety and immunogenicity of BioThrax (Anthrax Vaccine Adsorbed) and AV7909 (Anthrax Vaccine Adsorbed plus CPG 7909 adjuvant) using a post-exposure prophylaxis dosing regimen in adults ≥ 66 years of age in stable health. The safety and immunogenicity profile of BioThrax and AV7909 in adults ≥ 66 years of age will also be compared to the safety and immunogenicity profile of subjects 18-50 years of age in stable health. The main study goal is to determine optimal dosing for AV7909 in the elderly population. Subjects will receive either 3 doses of BioThrax, 3 doses of AV7909, or 2 doses of AV7909 and 1 dose of placebo. Doses will be administered approximately 14 days apart. Subjects will be followed for safety assessment for 12 months following the last dose. The expected study duration is approximately 14 months per subject.
This study is designed to assess the safety and ability of BioThrax and AV7909 anthrax vaccines to generate an immune response in adults ≥ 66 years of age in stable health in comparison to adults 18-50 years of age in stable health.