Is it possible that smallpox disease will ever come back?

Bioterrorism: It could only happen if the virus was reintroduced into the world through bioterrorism.

Not naturally.: The WHO announced worldwide eradication of smallpox on May 8, 1980. Smallpox has no animal reservoirs. So Smallpox would not return naturally. The American public has not received routine smallpox vaccinations since 1972. All natural sources of smallpox have been eradicated. According to the CDC, “The U.S. government has enough vaccine to vaccinate every person in the United States.”