Biodefense refers to measures to restore biosecurity to a group of organisms who are, or may be, subject to biological threats or infectious diseases. Biodefense is frequently discussed in the context of biowar or bioterrorism, and is generally considered a military or emergency response term.
Biodefense applies to two distinct target populations: civilian non-combatant and military combatant (troops in the field). Protection of water supplies and food supplies are often a critical part of biodefense.
Military biodefense in the United States began with the United States Army Medical Unit (USAMU) at Fort Detrick, Maryland, in 1956. (In contrast to the U.S. Army Biological Warfare Laboratories [1943–1969], also at Fort Detrick, the USAMU's mission was purely to develop defensive measures against bio-agents, as opposed to weapons development.) The USAMU was disestablished in 1969 and succeeded by today's United States Army Medical Research Institute of Infectious Diseases (USAMRIID).
The United States Department of Defense (or "DoD") has focused since at least 1998 on the development and application of vaccine-based biodefenses. In a July 2001 report commissioned by the DoD, the "DoD-critical products" were stated as vaccines against anthrax (AVA and Next Generation), smallpox, plague, tularemia, botulinum, ricin, and . Note that two of these targets are toxins (botulinum and ricin) while the remainder are infectious agents.