Smallpox was officially declared eradicated from the world in 1980. Earlier, in 1972, over 50 nations signed the Biological Weapons Convention renouncing this entire category of weapons. Despite this international agreement, both the United States and the Soviet Union continue to vaccinate their military troops against smallpox, thus implying that each fears the other might still use it in biological warfare. Vaccination is not a harmless procedure, and vaccinia infections continue to be reported in troops and their contacts. Negotiating an end to the vaccination of troops would be a final step in ending the fear of smallpox.