There is no immediate, direct threat of a bioterrorist attack using smallpox. No bioterrorist attack using smallpox has happened in modern times. Throughout history, though, some people have used smallpox to their advantage by deliberately infecting their enemies with the disease.

Why is Smallpox a Concern?

Public health authorities are concerned about smallpox because it is a serious—even deadly—disease. Today, there are only two labs in the world that are approved to have the smallpox virus for research: the Centers for Disease Control and Prevention (CDC) in the United States and the Russian State Centre for Research on Virology and Biotechnology in the Russian Federation. There is credible concern that in the past some countries made the virus into weapons, which may have fallen into the hands of terrorists or other people with criminal intentions.

The last natural outbreak of smallpox in the United States happened in 1949. The last naturally spread case in the entire world happened in 1977. The World Health Assembly declared smallpox eradicated in 1980. Even a single confirmed case of smallpox today would be considered an emergency.

If the virus that causes smallpox were used in a bioterrorist attack, people who come into contact with the virus would be at risk of getting sick. By 1972, the smallpox vaccine was no longer given routinely in the United States. As a result, most people born in the United States after 1972 have not been vaccinated against the disease. Some people have been vaccinated through the military or because they were part of Smallpox Response Teams that were formed after the 9/11 terrorist attacks. These vaccination efforts are part of the larger plan to prepare for a bioterrorist attack. However, the vaccine does not give lifelong immunity, and people who have been vaccinated against smallpox before may still need to be revaccinated in a smallpox emergency.

What Might a Bioterrorist Attack with Smallpox Look Like?

Most likely, if smallpox is released into the United States as a bioterrorist attack, public health authorities will find out once the first person sick with the disease goes to a hospital for treatment of an unknown illness. Doctors will examine the person and use tools developed by CDC to figure out if the person’s signs and symptoms are similar to those of smallpox. If doctors suspect the person has smallpox, they will care for the person and isolate them in the hospital so that others do not come in contact with the smallpox virus. The medical staff at the hospital will contact local public health authorities to let them know they have a patient who might have smallpox.

Local public health authorities would then alert public health officials at the state and federal level, such as CDC, to help diagnose the disease. If experts confirm the illness is smallpox, then CDC, along with state and local public health authorities, will put into place their plans to respond to a bioterrorist attack with smallpox.