Smallpox

       Sometimes smallpox is described as the most devastating disease in human history, and the eradication of the disease — there has not been a naturally acquired case since 1977 — ranks as, arguably, the greatest modern public health achievement. "If it's destroyed, the statement is made that after this date, any scientists, any lab, any country that has that smallpox virus is guilty of crimes against humanity," said Dr. DA Henderson, former director of the campaign to eradicate the disease and author of the book "Smallpox: Death of a Disease" (Prometheus Books, 2009).

       Destruction of the remaining virus also would eliminate the possibility of accidental release. Others, however, warn that labeling possession of the virus a crime against humanity will in no way deter terrorists, and that without the live smallpox virus, called variola, we won't be able to prepare for the worst. It is possible for humans to catch other closely related pox viruses, and it's also possible that a smallpox-like virus could re-emerge from the remaining pox viruses, Hruby said. Variola, which causes smallpox, belongs to a family of pox viruses that include camelpox, monkeypox, cowpox, buffalopox and others. The variola virus is faithful to its human host; other animals do not carry or spread it.

[How Smallpox Changed the World]

       The version used to eradicate smallpox worldwide was based on a different, but closely related, pox virus called vaccinia, according to Jonathan Tucker, a biosecurity expert and author of "Scourge: The Once and Future Threat of Smallpox" (Atlantic Monthly Press, 2001). A decade-long WHO global vaccination campaign to eradicate smallpox was successful; the last natural case occurred in October 1977, in Somalia. Destroying the virus is the natural end to the eradication campaign, according to Hammond.

       In the years after eradication, countries destroyed or transferred their stocks of the virus until only two designated repositories remained: at the Centers for Disease Control and Prevention in Atlanta and the State Research Institute for Viral Preparations in Moscow. Since then the United States has been hesitant to destroy the virus in case there are undeclared stocks in countries like North Korea and Iran, according to Tucker. Those nations have denied possessing the virus.

       The World Health Assembly decided in 1999 to keep the virus around temporarily for research to improve defenses against it, including a safer version of the vaccine, antiviral medication to treat those already infected, and a way to simulate human smallpox in an animal for research. Hruby is working on an antiviral treatment for those who have been infected too long for the vaccine to be effective. If approved by the Food and Drug Administration, this could become one of the first treatments against smallpox.

       Meanwhile, destroying the virus and labeling its destruction a crime against humanity will not deter terrorists, he said. In 2002, scientists built the first synthetic virus – relying on instructions found on the Internet, no less. At that time, the WHO called on all nations to destroy their collections of smallpox virus or transfer them to the WHO-sanctioned collections at one of two labs in Russia or the United States. Once it was eradicated, we stopped routine civilian vaccination for smallpox. In fact, people under the age of 30 have little or no immunity to smallpox. Should an outbreak occur, we do have effective vaccines that could be deployed to protect most Americans. Globally, work is under way to develop and test these vaccines. Destruction of the last securely stored viruses is an irrevocable action that should occur only when the global community has eliminated the threat of smallpox once and for all.