PENNSYLVANIA, USA — Note: The video is from Nov. 16.
A worker at a Pennsylvania laboratory that conducts vaccine research discovered frozen vials labeled "Smallpox," a spokesperson for the U.S. Centers for Disease Control and Prevention said Wednesday.
"The CDC, its Administration partners, and law enforcement are investigating the matter, and the vials’ contents appear intact," the spokesperson said in a statement. "The laboratory worker who discovered the vials was wearing gloves and a face mask.
"There is no indication that anyone has been exposed to the small number of frozen vials."
The spokesperson did not say where the Pennsylvania laboratory was located.
According to CDC, there are only two WHO-designated sites that are authorized to store and use smallpox virus for research: The CDC's facility in Atlanta, and the Russian State Centre for Research on Virology and Biotechnology, Koltsovo, Novosibirsk Region, Russian Federation.
The CDC spokesperson said more details will be provided as they become available.
Before smallpox was eradicated, it was a serious infectious disease caused by the variola virus. It was contagious—meaning, it spread from one person to another. People who had smallpox had a fever and a distinctive, progressive skin rash.
Most people with smallpox recovered, but about three out of every 10 people with the disease died. Many smallpox survivors have permanent scars over large areas of their body, especially their faces. Some are left blind.
According to the CDC, smallpox was eradicated, and no cases of naturally occurring smallpox have happened since 1977. The last natural outbreak of smallpox in the United States occurred in 1949.