• Only infectious disease that has been eardicated

  • Major reasons:


  • Airborne (not droplet as per slide below w)

  • Clinical symptoms



A ProMED-mail post

[The current report follows:]

Frozen vials labeled "smallpox" that were discovered in a freezer at a vaccine research facility in Pennsylvania "contain no trace of virus known to cause smallpox," federal health officials said.

The Centers for Disease Control and Prevention said on Thursday [18 Nov 2021] that testing showed the vials contain "vaccinia, the virus used in smallpox vaccine" and not the variola virus, which causes smallpox. CDC had said on Monday [15 Nov 2021] that the vials "were incidentally discovered by a laboratory worker" who was wearing gloves and a face mask while cleaning out the freezer. CDC said no one was exposed to the contents.

Smallpox is a deadly, infectious disease that plagued the world for centuries and killed nearly 1/3 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 2 sites designated by the World Health Organization where stocks of variola virus are stored and used for research: the CDC facility in Atlanta and a center in Russia [State Research Centre of Virology and Biotechnology in Novosibirsk, Siberia, 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 CDC.

[Given that smallpox has been eradicated from the world, it is a relief to learn that the vials did not contain variola (smallpox) virus. This situation illustrates the need to keep an accurate inventory of freezer contents to avoid surprises. This false alarm recalled a situation in July 2014 when employees found 6 forgotten vials containing variola virus when they were preparing to move a lab from the Food and Drug Administration's Bethesda, Maryland campus to a different location. The laboratory had been used by the NIH but was transferred to the FDA in 1972.

When the scientists found the vials, they immediately put them in acontainment lab, and on 1 Jul 2014 notified the branch of the government that deals with toxic substances, called the Division of Select Agents and Toxins. CDC said previously there is no evidence that any of the vials was breached, nor were any of the lab workers exposed to the virus.

On Monday [7 Jul 2014], law enforcement agencies transferred the vials to CDC's high-containment facility in Atlanta. CDC is one of only 2 official WHO designated repositories for smallpox. The then CDC director Tom Frieden said his scientists worked through the night on the samples as soon as they got them. Testing confirmed that there was variola DNA in the vials. Additional test results showed "evidence of growth" in samples from 2 of the vials, suggesting that the smallpox virus was alive (see Smallpox - USA (02): forgotten stock discovered

The general presumption is that there are no remaining stocks of variola virus anywhere in the world, except for those in the USA and Russia. One hopes that this is true, since the world population has again become susceptible to this transmissible virus.