We just completed a century that saw more than 65 million people die in two great world wars. This staggering toll pales, however, compared to the carnage caused by the smallpox virus. Best estimates indicate that 300-500 million people died from smallpox in the 20th century – several times the numbers of deaths from all wars combined.

Humankind’s greatest single accomplishment of the last century arguably was the eradication of smallpox. Thanks to the smallpox vaccine and a global immunization campaign, the World Health Organization certified the world smallpox-free in 1980. So vanished a virus that caused disfiguring pustular rash, internal hemorrhage and excruciating death.

Smallpox is back.

Since the fall of the Soviet Union in 1991, many of its military secrets have been divulged. One disturbing revelation is that a Soviet biological warfare program produced millions of infectious doses of smallpox virus that still exist today. Through black markets, the virus is believed to be in the hands of terrorist and rebel groups and possibly even lone individuals. It would be a simple exercise for any of these to mount a devastating terrorist attack with smallpox.

If it is important to prevent an attack with nuclear weapons, it is just as crucial to prevent an attack with bioweapons such as smallpox virus. Militaries, including the U.S., spend billions of dollars to develop and maintain “stealth” technologies, such as aircraft invisible to radar, capable of striking with little or no warning. Smallpox may be the ultimate stealth weapon. Tens of millions of smallpox virus particles will easily fit into a hand-held container. Using store-bought materials assembled into a primitive device, the virus particles can be aerosolized into a public building. The microbe would be invisible and odorless, and could be unleashed without being noticed.

The consequences of an attack are starkly illustrated in a forthcoming book by bioterrorism expert Michael T. Osterholm entitled Living Terrors. Without an explosion or any sound whatsoever, a terrorist attack using smallpox would go completely unnoticed by either security personnel or its victims. Only 8 – 16 days later when victims show up in hospital emergency rooms will the enormity of the attack become apparent. By then, it will be too late. Highly contagious, the smallpox virus from a single assault could strike hundreds of thousands of people. More than 30% would die. Survivors would suffer a permanent and disfiguring rash on the face.

Beyond the dreadful human consequences of a smallpox bioterrorism attack are momentous social, political and economic consequences. Hospitals are unprepared to deal with such an onslaught. The ranks of front line health care workers would be decimated by the contagion. Confidence in public institutions and elected officials would erode. We would fear going outside our homes, never knowing when and where the next invisible, lethal attack would happen. The workforce and productivity would dwindle.

Call to Action

The United States is dangerously underprepared to combat a bioterrorist attack using smallpox. Few individuals have been vaccinated against smallpox since 1972 when eradication allowed immunization to be discontinued. And protective immunity is thought to have worn off for all but 10%-20% of those who were vaccinated. Thus, approximately 90% of the U.S. population are susceptible to smallpox. Our stores of currently available vaccine are extremely meager and inadequate to handle an outbreak.

The government has taken the first steps to prepare for and prevent such an attack. The CDC received funds in 1999 to develop coordinated federal, state and local plans, educate health care and public health professionals about handling such an attack, and developing and strengthening surveillance systems for early detection of outbreaks. Last week, the government ordered 40 million doses of smallpox vaccine for a stockpile. These initial steps are positive but much more needs to be done. The smallpox vaccine stockpile should have at least 100 million doses. The estimated cost for this expansion of the stockpile is under $100 million – cheap compared to nuclear preparedness. Serious consideration should be given to accelerating vaccine research and development for other potential bioterrorism agents.

The U.S. – indeed, the world – is vulnerable to a catastrophic bioterrorist attack. Production of economical and effective vaccines to prevent the calamity is feasible and would be an easily attainable countermeasure.

H. R. Shepherd is chairman of the Albert B. Sabin Vaccine Institute, a nonprofit education and research institute based in New Canaan, Connecticut. Peter J. Hotez, M.D., Ph.D. is an institute advisor and chair of the Department of Microbiology and Tropical Diseases at The George Washington University Medical Center in Washington, DC.