Flight Surgeon Maj. Timothy Ballard prepares to administer the final anthrax shot to Secretary Cohen. U.S. Air Force Flight Surgeon Maj. Timothy Ballard (right) prepares to administer the final shot in the six-dose series of anthrax inoculations to Secretary of Defense William S. Cohen (left) in Cohen's Pentagon office on Sept. 24, 1999. Following this shot, a once-a-year booster is all that will be required to maintain resistance to anthrax. Ballard is attached to the 11th Medical Group. SHARE: Download: Full Size (0.04 MB) Credit: VIRIN: 963894-G-BIJ53-714.jpg Photo Gallery