Vials labeled as smallpox were discovered in a Pennsylvania lab, the Centers for Disease Control and Prevention said Wednesday.
The frozen vials “were accidentally discovered by a lab worker while cleaning a freezer at a facility that conducts vaccine research in Pennsylvania,” a CDC spokesman said in a statement to NBC News.
The contents of the vial appeared to be intact and the CDC is cooperating with police to investigate, the agency said.
“The worker who discovered the vials wore gloves and a face mask. There is no indication that anyone was exposed to the small number of frozen vials. We will provide additional details when they become available, “the spokesman added.
Smallpox was wiped out in the 1970s, but vaccines still exist in the event of an outbreak, according to the CDC. But once a person develops a smallpox rash, the vaccine cannot protect them. About 3 out of 10 people with smallpox die.
NBC Philadelphia reported that the vials were found at a Merck facility in Montgomery County, about 30 miles northwest of Philadelphia. Only two facilities in the world are thought to have doses of the virus: CDC’s headquarters in Atlanta and a Russian laboratory.
Merck did not respond to a request for comment Wednesday. The Department of Health and Human Services also did not respond to a request for comment.