Isn't it eradicated?

Although the World Health Organization (WHO) declared smallpox eradicated in 1980, this contagious and deadly disease caused by the Variola virus remains high on the list of possible bio-terror threats.

The danger of recurrence is clear and present. 

It would be very simple to use the virus as a weapon. Natural sources of smallpox virus include UN repositories, archived laboratory specimens, mutation of a related poxvirus and resurrection of the virus outside labs. Intentional release might result from unauthorized acquisition from UN repositories, offensive state programs or laboratory genetic synthesis. 

These potential sources demonstrate that the dangers of a re-emergent smallpox virus are real and an urgent response is required. 

It would be very simple to use the virus as a weapon