"One of the most significant and serious current examples of the harm that can be set into motion by eliminating a disease-bearing pathogen from the human environment is associated with the present status of smallpox. The 23 year-long, global eradication of smallpox that has been achieved is a public health and medical triumph of the late twentieth century. However, the freedom attained from this infectious and contagious disease, and the suspension of smallpox vaccination that it has made possible, have rendered the world population highly vulnerable to the intentional or unintentional release of the variola virus that causes smallpox. This has heightened the anxiety that now exists about the threat of biological warfare and terrorism, and the possibility that the smallpox variola might be used as a weapon. In the United States, the government has responded with a plan to reintroduce smallpox vaccination, beginning with the vaccination of members of the military, hospital workers and health professionals, and firefighters and police who, in the instance of a biological warfare attack, would be most likely to have “front-line” contact with the persons who have diagnosed or undiagnosed smallpox. This plan has ignited debate about how many and which persons to vaccinate, about the risk of the adverse effects that will result from vaccination (ranging in gravity from diffuse skin eruptions to brain damage and death), and about how to monitor and minimize them."