Oct. 24, 2001 -- Say "worst-case scenario" to any bioterror expert and you'll get a one-word reply: smallpox.
Since Sept. 11, 2001, the world has learned to imagine the unimaginable. It's hard to think of why anyone would bring back "the most terrible of the ministers of death," as 19th century historian Thomas Babbington Macaulay called it. The eradication of smallpox, announced in 1980, ranks among the greatest of human achievements.
Few diseases are as contagious, as deadly, or as horrible as smallpox. It killed at least 300 million people in the first 80 years of the 20th century -- more than three times the number killed in all the world's wars. Because few people now have any natural or vaccine immunity, new bouts of the disease would be far more deadly.
Donald A. Henderson, MD, MPH, oversaw the international smallpox eradication effort. He's now director of the Johns Hopkins Center for Civilian Biodefense Studies and serves as bioterror advisor to the federal government. Henderson spoke with WebMD in January 2001.
"The probability of an attack by terrorists using the smallpox virus, we feel to be very low, for a number of reasons," Henderson says. "To obtain and grow organisms like smallpox ... is [very] complicated and is not so easily done by persons with only limited training. However, the Soviet Union produced large amounts of organisms of various types, and the laboratories which produced those are now very poorly funded. Many of the scientists have left the laboratories, and some have been recruited to work in other countries. Thus, there is the possibility that individuals with bioterrorism in mind could recruit Russian expertise at very little cost or might be able to obtain some of the finished material ready for use."
As small as this risk may be, Henderson says a release of smallpox today would be "a major catastrophe." This is also the opinion of C.J. Peters, MD, former chief of special pathogens at the CDC and now professor of microbiology at the University of Texas Medical Branch, Galveston.
"We are worried that other people might have smallpox and would use it to start a smallpox epidemic. That is why the governmenthas 7 1/2 million doses of smallpox vaccine stored away and why they are contracting to take 300 million more doses," Peters tells WebMD."The government has had much experience with smallpox in the past.Cases were introduced in the 1960s and 1970s from overseas.And it was possible to stop smallpox transmission by vaccinating all the people in contact with the cases."
Plans are underway to stretch existing smallpox vaccine doses to cover three or even five times as many people. This stopgap measure is of critical importance. The only way to stop a smallpox outbreak is to vaccinate a ring of people who have been around infected people.