Smallpox is a highly contagious and sometimes fatal disease that has been eradicated after a worldwide vaccination program. The last US case was in 1949; the last global case was in 1977 in Somalia.
The vials were labeled "variola," another name for smallpox, and they appear to date from the 1950s, the US Centers for Disease Control and Prevention said in a statement.
They were found in an unused portion of a storeroom in an FDA laboratory, located on the National Institutes of Health campus in Bethesda, Maryland.
There is no evidence that the vials had been opened, "and onsite biosafety personnel have not identified any infectious exposure risk to lab workers or the public," the CDC said.
The vials have been moved to a high-security lab at the CDC headquarters in Atlanta, Georgia.
Initial tests came back positive for smallpox, and further testing will be done to determine if it is viable, or able to grow in tissue culture.
"This testing could take up to two weeks. After completion of this testing, the samples will be destroyed," the CDC said.
"If viable smallpox is present, the World Health Organization will be invited to witness the destruction of these smallpox materials, as has been the precedent for other cases where smallpox samples have been found outside of the two official repositories."
According to international agreements, only two places in the world are authorized to keep samples of smallpox: the CDC in Atlanta and the State Research Centre of Virology and Biotechnology (VECTOR) in Novosibirsk, Russia.
The CDC said it was notified by the NIH of the discovery on July 1 when workers were preparing to move the FDA lab from the NIH to the FDA's main campus.
The CDC Division of Select Agents and Toxins (DSAT) and the FBI are investigating how the vials got there.
Comment: According to the WHO, smallpox has been eradicated. Why then is it still necessary to preserve samples in two labs in the US and Russia? The truth is, it hasn't been eradicated, and still infects people today. There is a growing suspicion that smallpox has been labeled "eradicated" to be able to terminate the smallpox vaccination programs, because it became clear that vaccinating against smallpox was not only ineffective, but increased fatality rates compared to the un-vaccinated. Notwithstanding the fact that smallpox is still in the wild - under different names like monkeypox, but indistinguishable from smallpox - WHO declared smallpox eradicated, possibly to escape litigation, while preserving the vaccine paradigm.
The only effect of vaccines that has consistently been shown is immunosuppression.
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Smallpox was declared eradicated, yet still infects humans today.