The best defence against bioweapons has already been invented by evolution.

Bioweapons are considered from the viewpoint of the mutual evolution of microbe/victim ecological systems. Cases considered include accidental, experimental, and real exploitation of bioweapons as well as other cases in the history of epidemics, and also experimental investigations. It is proposed here that speculations about bioweapon's very high mass annihilating ability are based on over-extrapolation from limited data selected from the ancient history of epidemics and on a false supposition that all people are susceptible to any bioweapon's infectious agent. The history of epidemics, clinical and genetic observations, data from experimental investigations, and results of accidental, experimental, and real exploitation of bioweapons do not confirm the mass annihilating capability of bioweapons. Many people possess constitutional (genetic) immunity presumably formed by natural selection over many human generations. This genetic protection exists in an individual prior to infection. The power of constitutional immunity played an important role during all human evolution. Its protective capability continues to defend humanity from mass annihilation by both epidemics and bioweapons. In this context of constitutional immunity for the majority of individuals, the main goal of modern medicine is to identify and defend the defenseless ones.