The threat of bioterrorism returns the fear of smallpox.

In t roduct ion Recent revelations about the biological weapons programs of Iraq and the former Soviet Union and attempts by cults and other groups to develop biological weapons have elevated the threat of a deadly bioterrorist attack. A major diplomatic effort aimed at strengthening the Biological Weapons Convention is underway to help reduce this threat and public health authorities are scrambling to develop contingency plans should such an attack occur. Much of the effort is focused on developing a response capability to anthrax or plague, which are among the most likely diseases that would be spread by a biological weapons release. But there is also heightened fear that bioterrorists could have acquired the smallpox virus. This possibility raises numerous policy issues, including what to do about the remaining known stocks of smallpox virus in the United States and Russia, and whether to reintroduce vaccination against a disease that has been eliminated and no longer a natural threat to humankind.