(CNN) – Several flasks marked “smallpoxat a Vaccine Research Facility in Pennsylvania, the US Centers for Disease Control and Prevention (CDC) said Tuesday.
“There is no indication that anyone has been exposed to a small number of frozen vials,” the CDC said in an emailed statement to CNN.
“The frozen vials called ‘smallpox’ were accidentally discovered by a lab worker while cleaning the freezer at a facility conducting vaccine research in Pennsylvania. The CDC, its management partners, and law enforcement are investigating the matter and the contents of the vials appear to be intact,” the CDC added. on diseases.
“The lab worker who discovered the flasks was wearing gloves and a mask. We will provide more details as they become available.”
The World Health Organization declared smallpox eradicated in 1980 after a concerted global vaccination effort.
Before that, the virus, which is easily transmitted from person to person, infected 15 million people annually and killed about 30% of them. The last known outbreak in the United States was in 1947.
In 2014, National Institutes of Health (NIH) staff They found six vials of smallpox In an unused warehouse as they pack things to go from a lab on the National Institutes of Health campus in Bethesda, Maryland, to the move. Two of the vials contained viable virus. Center for Disease Control They said at that time There is no evidence that anyone has been exposed to the contents of any of the vials.
Governments have debated whether to preserve samples of the virus or destroy all known copies. Most routine vaccination stopped in 1972, but vaccination of military personnel and some researchers continues. The CDC recommends that people who need long-term protection receive smallpox boosters every 3-5 years, although at least one study suggests that vaccinated people may have at least some immunity. forever.