nation, described in Chapter 2) that followed (IOM, 1999; Radetsky, 1999). The combined extraordinary efforts of health care and public health workers from across the world led to the eradication of smallpox, officially acknowledged by the WHO in 1980 (Barquet, 1997).

The last endemic case of smallpox in the world occurred in 1977 in Somalia. Since that time, the virus has ceased to exist in the wild, with official repositories for live variola virus remaining only at two secure locations in Atlanta, Georgia, in the United States, and in Novosibirsk, Russia. Subsequently, the WHO Committee on Orthopoxvirus Infections planned a coordinated destruction of all existing stocks of smallpox virus, all stored clinical material containing virus, and all intact virus DNA in June 1999. However, by the late 1990s, the scientific and public health communities had found both scientific and civil defense reasons for retaining the stocks of live virus. In 1998, an Institute of Medicine committee was convened “to assess the scientific and medical information that might be lost were live variola virus no longer available for research purposes” (IOM, 1999). The Assessment of Future Scientific Needs for Variola Virus found that “much scientific information, particularly concerning the human immune system, could be learned through experimentation with live variola virus,” but “the most compelling need for long-term retention of live variola virus is for the development of antiviral agents or novel vaccines to protect against a reemergence of smallpox due to accidental or intentional release of variola virus” (IOM, 1999). After international dialogue on the fate of the known smallpox virus stocks, the WHO did not proceed with the planned destruction of the virus but resolved to temporarily retain variola stocks for future use in specific scientific endeavors and in research activities related to the preventing and responding to bioterrorism. Variola research accomplishments and outcomes would be reviewed periodically (WHO, 2002, 2003).

The last endemic case of smallpox in the United States was in 1949, and vaccination of the general public in this country ended in 1972 (DHHS, 2003). The reintroduction of civilian smallpox vaccination in 2003 called on the public health and health care communities to recall and prepare to fight a mostly forgotten microbe.

Variola virus is a specifically human pathogen, and there are no known animal reservoirs for the disease (Fenner et al., 1988). There are two types of the disease: variola major and variola minor. The latter has been found to cause a much milder form of the disease, with a fatality rate of 1 percent, compared to the 30 percent rate of variola major (Henderson et al., 1999). Five clinical types of variola major have been identified: the ordinary type,