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Notice to Readers: 25th Anniversary of the Last Case of Naturally Acquired Smallpox

On October 26, 1977, the last case of naturally acquired smallpox occurred in the Merca District of Somalia. In May 1980, the World Health Assembly certified the world free of naturally occurring smallpox. The eradication of a disease was an unprecedented accomplishment. Eradication efforts for both paralytic poliomyelitis and dracunculiasis (i.e., guinea worm disease) are ongoing. Beyond the benefit to the world population's health and economy, smallpox eradication demonstrated the benefits of international commitment and cooperation toward a common cause in public health. Improvements made in international vaccination programs, global disease surveillance, and public health logistics systems that were results of the smallpox eradication program continue today (1).

Although smallpox was eradicated in 1977, the risk for importation of disease into the United States had greatly decreased before that time. As a result, the United States discontinued routine smallpox vaccinations for the general population in 1971, and the Advisory Committee on Immunization Practices recommended against routine vaccination of health-care workers in 1976. The last case of smallpox in the United States occurred in 1949. An MMWR report in 1997 commemorating the 20th anniversary of the eradication of smallpox noted that smallpox vaccine and its eradication of smallpox disease were on the list of things that need be done only once in the history of the world (1).

The U.S. public health system is preparing for the potential use of smallpox (variola) virus as a bioterrorism agent. Although preparedness efforts have been ongoing since at least 1999 and a strategic plan for preparedness and response against biologic and chemical terrorism was published in April 2000 (2), the terrorist attacks against the United States on September 11, 2001, prompted extensive review of policies and procedures about potential acts of bioterrorism, especially the intentional release of smallpox virus. To enhance preparedness, the U.S. Department of Health and Human Services has contracted for production of enough smallpox vaccine for the entire U.S. population if vaccination becomes necessary, developed a plan for responding to a smallpox attack (, and is reviewing whether increased vaccination before an attack is warranted and how such a vaccination program would be implemented. A final U.S. policy on smallpox vaccination is pending. Additional information on smallpox is available at


  1. CDC. Smallpox surveillance---worldwide. MMWR 1997;46:990--4.
  2. CDC. Biological and chemical terrorism: strategic plan for preparedness and response. MMWR 2000;49(No. RR-4).

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