'Smallpox' Vials Found in Pennsylvania Facility's Freezer Did Not Contain Virus: CDC

Frozen vials labeled as "Smallpox" that were found in a Pennsylvania vaccine research facility's freezer did not contain the virus that causes smallpox infection, the Centers for Disease Control and Prevention said Thursday. The federal health agency found that the vials contain "vaccinia, the virus used in smallpox vaccine," rather than the variola virus that can cause people to contract the historically deadly and infectious illness, the Associated Press reported.

The U.S. government was informed about the vials on Monday after they "were incidentally discovered by a laboratory worker" who was cleaning out a freezer at a research facility run by the pharmaceutical company Merck, the CDC said. The worker was wearing gloves and a face mask at the time, and nobody was exposed to the contents of the vials, according to the agency.

"The freezer facility was immediately secured and staff followed standard protocols for notifying CDC of such a potential discovery. The vials were sent securely to CDC for testing on November 18 to determine what they contained," the CDC said in a statement.

Upon investigation, health officials were able to determine that the vials "contain no trace of virus known to cause smallpox." The vaccinia virus that was detected inside the vials is used to produce smallpox vaccine and is the origin of the word "vaccine," CNN reported.

The CDC said that it "is in close contact with state and local health officials, law enforcement, and the World Health Organization about these findings."

For more reporting from the Associated Press, see below:

Vials Do Not Contain Smallpox
Frozen vials labeled as “Smallpox” that were found in a Pennsylvania vaccine research facility’s freezer did not contain the virus that causes smallpox infection, the Centers for Disease Control and Prevention said Thursday. The headquarters for Centers for Disease Control and Prevention is shown on Friday, March 6, 2020 in Atlanta, Georgia. Ron Harris/AP Photo

Mark O'Neill, a spokesperson for the Pennsylvania Department of Health, told the New York Times that the vials were found at a Merck facility in Montgomery County.

It was not clear why the vials were in the freezer.

Smallpox is a deadly, infectious disease that plagued the world for centuries and killed nearly a third of the people it infected. Victims suffered scorching fever and body aches, and then spots and blisters that would leave survivors with pitted scars.

The United States ended routine childhood vaccination against the disease by the early 1970s and said the last natural outbreak in the country occurred in 1949. In 1980, the World Health Assembly declared smallpox eradicated.

There are two sites designated by the WHO where stocks of variola virus are stored and used for research: the CDC facility in Atlanta and a center in Russia.

Smallpox research in the United States focuses on the development of vaccines, drugs and diagnostic tests to protect people against smallpox in the event that it is used as an agent of bioterrorism, according to the CDC.

Smallpox History
Smallpox plagued people around the world for centuries, killing nearly a third of all those it infected. The World Health Organization declared the deadly, infectious illness eradicated in 1980. Dr. Walter X. Lehmann, left, and Dr. Kurt L. Brunsfeld, right, vaccinate two unidentified women for smallpox April 14,1947, as others await their turn in New York City Health Department building. Tony Camerano/AP Photo