Naturally occurring smallpox is a serious infectious disease that is usually spread from person to person through close contact. It is caused by the variola virus. Across studies, naturally occurring smallpox (variola major) has a fatality rate of approximately 30%. Smallpox can also cause permanent disabilities, such as terrible scarring and blindness. There is no FDA-approved treatment for smallpox disease. The only approved preventive intervention is vaccination. The last case of smallpox in the United States (U.S.) occurred in 1949, and routine vaccination in the U.S. was stopped in 1971. The last naturally occurring case in the world occurred in Somalia in 1977, and the World Health Organization determined in 1980 that the global vaccination campaign against smallpox had been successful in eliminating naturally occurring disease from the world. As a result, routine vaccination against smallpox on a worldwide basis was stopped because it was no longer necessary for prevention. More recently, the U.S. government has become concerned that smallpox could be used as a weapon of bioterrorism, and is developing new vaccination strategies for both military personnel and civilians. Smallpox (variola major) is a particularly dangerous biological weapon threat because of the severity of the illness it causes and the fact that it can be spread from person to person. | 
