Smallpox and Bioterrorism: A Growing Threat

By S. Van McCrary, Health Law & Policy Institute

A rapidly growing body of research suggests that the danger of intentional release of smallpox virus by various terrorist, or even governmental, organizations is increasing. A recent literature search revealed over 200 publications on related issues during the past two years. This topic was brought into sharper focus in a July article by Richard Preston (The New Yorker, July 12, 1999, pp. 44-61), the author who "popularized" the ebola virus in his book The Hot Zone.

Smallpox, caused by the virus variola, has killed more persons throughout history than any other infectious disease, including bubonic plague (an estimated 500 million persons died from smallpox in the 20th century alone). Symptoms include a high fever and a rash of pustules over the body. The disease is highly contagious, is transmitted through the air, and has a mortality rate of up to 33%. A global vaccination program from 1966 through 1977 brought the disease under control. The last naturally occurring case of variola major, the most severe form, was in October 1975 in Bangladesh, and the last case of variola minor followed in 1977. Since that time naturally occurring smallpox has ceased to be a threat and in 1980 the World Health Organization (WHO) declared smallpox eradicated. However, the virus continues to exist in an undetermined number of research laboratories around the world. In 1972, the U.S. stopped routine vaccinations for smallpox and most of the population is now believed to be vulnerable to it (this is true even for persons who were immunized earlier because the immunity conferred by vaccination does not persist permanently). Experts currently believe that a single case of smallpox anywhere on earth would be a global medical emergency.

The U.S. government has created a list of organizations that it suspects either have secret supplies of smallpox virus or are trying to obtain them. According to Preston's article, the list is said to include China, Cuba, India, Iran, Iraq, Israel, North Korea, Pakistan, Russia, and Serbia, as well as the terrorist group of Osama bin Laden and the Aum Shinrikyo sect in Japan. A secret federal intelligence assessment, completed in 1998 and based on substantial evidence including recently vaccinated North Korean soldiers, concluded that Iraq, North Korea and Russia are likely to be concealing smallpox virus for military use. Evidence also suggests that in 1991 the Soviet Union tested a special missile warhead with refrigeration specifically designed to keep a micro-organism alive during flight and reentry. Research also indicates that Russia recently has engaged in, and may be continuing, significant research on military applications of smallpox although this is denied by Russian government scientists. Technology also exists widely to distribute a micro-organism through the air in a manner undetectable to persons nearby.

In June, experts met in Atlanta to evaluate the possible threats from bioterrorism. Smallpox was unanimously determined to be the greatest threat to the U.S., followed by anthrax. Anthrax, however, is not contagious and dissemination could be a challenging obstacle. In contrast, smallpox is readily disseminated from person to person. Earlier this year, a panel of the Institute of Medicine (IOM) concluded that preserving smallpox virus in U.S. laboratories may provide significant scientific opportunities for research on anti-viral drugs. This conclusion was used by the Clinton administration effectively to overrule an earlier recommendation by the WHO that all remaining laboratory stocks of the virus be destroyed.

Currently, the U.S. supply of smallpox vaccine is very limited in quantity (an estimated seven million doses) and may be declining in efficacy due to age. The old vaccine was made using procedures that would not satisfy current standards of the federal Food and Drug Administration (FDA), so it may be a number of years before sufficient quantities of vaccine could be available. A single case that resulted in a small outbreak in Yugoslavia in 1972 required 18 million doses to control, and experts have estimated that an outbreak started by 100 initial cases from a bioterrorism event could necessitate administration of 100 million doses of vaccine. Experts disagree regarding the necessary time frame and cost for developing a new vaccine for smallpox, but a number of efforts are underway. According to Preston, however, these initiatives are experiencing both administrative and scientific delays.

The growing menace of smallpox used as a weapon of terror confirms the necessity of keeping the virus for research and proceeding on development of a new vaccine and anti-viral drugs with all deliberate speed. Considering the high efficacy and relative safety of the old vaccine, it may be appropriate in this particular case to consider relaxing FDA standards for vaccine production and development. As Secretary of Defense William Cohen aptly noted on July 26 in The Washington Post (p. A19), "there is not a moment to lose."