SOUTH JERSEY (KYW Newsradio) — A worker at a Merck & Co. vaccine research facility in Pennsylvania found four vials labeled "smallpox" while cleaning out a freezer, according to the CDC. The agency says there is no indication that anyone was exposed to the deadly disease.
Officials say the lab worker was wearing gloves and a mask, and there is no sign of infection. The CDC says the contents of those vials appear to be intact.
Yahoo News reported that the lab was located somewhere outside of Philadelphia.
Smallpox, also known as variola, was declared eradicated in 1980 by the World Health Organization after a concerted global vaccination effort. Health officials, of course, would like to keep it that way.
Before then, the virus, which passes easily from person to person, infected 15 million people a year, and it killed about 30% of them.
Most routine vaccination for smallpox ended in the 1970s, though some people in the military and in research fields are still vaccinated. The last known outbreak in the US was in 1947.
Governments and health experts have argued about whether to keep samples of the virus or to destroy all known copies of smallpox. It is still unknown why this lab had these vials in the first place.
Smallpox is supposed to exist officially only in two places: at the CDC in Atlanta, and at its Russian counterpart. However, this isn't the first time something like this has happened. In 2014, employees of the National Institutes of Health found six vials of smallpox in an unused storage room in Bethesda, Maryland. Two of the vials contained viable virus. The CDC said at the time there was no evidence anyone had been exposed to the contents of any of the vials.
The CDC says it is investigating this most recent discovery.