If the Guinness Book of World Records had a category for mass murderers, variola major, the virus that causes this highly infectious, terrifying disease, would win easily. In the 20th century alone, smallpox killed more than 300 million people, more than three times the number killed in all wars, and many times the 22 million who have died from AIDS. Our problem today is that while we have no evidence that terrorists have planned smallpox attacks, if they do, we are not immune. Even with the recent good news about the availability of ample vaccine, the specter of battling a full-scale smallpox epidemic is staggering.
Smallpox spreads from person to person, usually by the respiratory route, and is so contagious that any face-to-face exposure to an active case can cause disease. It was named the Small Pox because the boils that appear are tinier than the ones caused by syphilis, the Great Pox. After a few days of sometimes severe flu-like symptoms, pustules develop all over the body, mirroring lesions inside the mouth and other mucous membranes. The pox remain about four weeks—a month of pain and horror. One-third of those afflicted with variola major die, usually from pneumonia; many others are blinded, and the rest are scarred and disfigured (a milder strain, variola minor, is much less fatal). There is no treatment—at least not yet. And for thousands of years, there was no way to prevent the disease. Then, in the 1790s, an English surgeon named Edward Jenner observed that milkmaids who had cowpox—a relatively harmless virus contracted from infected udders—didn't get smallpox. He also discovered that if you injected the pus of a milkmaid's cowpox lesion into the arm of a healthy boy, it would protect him from smallpox. The notion was considered preposterous at the time (Jenner was laughed out of many medical meetings), but it eventually led to the vaccine that has saved millions of lives.
Before the vaccine, smallpox meandered wherever it wanted, leaving peasants, kings and emperors dead in its wake—from Marcus Aurelius to King Louis XV. Even after Jenner's discovery, the disease continued to kill for another 200 years.
Let's play a game of hypotheticals. Imagine one terrorist releases the smallpox virus, perhaps by aerosol, in Oklahoma City. Because smallpox is invisible, odorless and tasteless, no one knows the virus is present until two weeks later, when the first cases appear. But by then, hundreds more have been exposed and the disease has spread to 25 states and many other countries, afflicting over three million people and causing the death of more than one million. Impossible? This "game" was actually played by policymakers months before the events of September 11, then the anthrax letters put smallpox in the headlines.
Last June, the Center for Strategic and International Studies, the Johns Hopkins Center for Civilian Biodefense Strategies and others conducted a senior-level war game called Dark Winter at Andrews Air Force Base outside Washington, D.C.
The results of Dark Winter convinced many that the devastation caused by smallpox might be worse than an atomic bomb. At the time of the game, we did not have enough vaccine. But even now, should an outbreak occur, less than 20 percent of us are currently protected. Why? We stopped routine vaccinations in 1972 because we assumed smallpox had been relegated to history. Epidemiologists thought the only storehouses of the deadly virus were the two very secure "legal" research labs at the Centers for Disease Control and Prevention (CDC) in Atlanta and Biopreparat in Russia.
The reappearance of smallpox would be much more than a theoretical exercise for any of us who originally defeated this terrible disease, including my former boss, D.A. Henderson, M.D., who was head of the WHO smallpox eradication program and is now director of the Office of Public Health Preparedness. For us, this is a personal war; we are fighting smallpox once more because human beings may have stolen a live virus and are now planning to let out the evil demon we bottled up two decades ago—or, worse, have created some modern bioengineered hybrid that is vaccine-resistant.
Looking Forward with Hope
In the face of all this danger, is there any hope? The answer is yes. We are much better off now than we were when the Dark Winter was played. Last year, epidemiologists were very concerned to learn that the WHO's vaccine safety net of 200 million doses had been destroyed in the late 1980s when the United States withheld funds and the agency was unable to pay $50,000 to refrigerate the supply. This past summer we thought we had only 15.4 million doses of vaccine, but now we know that soon we will have enough vaccine to protect the country, thanks to two discoveries: first, that our existing vaccine can be diluted to produce five, maybe even ten times as many doses; second, that there's an additional stock we didn't know about. Having enough vaccine, however, does not mean everyone can, or should, get it. Vaccination itself carries substantial risks, including a death rate of up to three per million immunized with the older formulations—a fact that makes us still vulnerable.
But today, the state health departments and the CDC have taken the experience we gained in eradicating smallpox two decades ago and brought it up to date in a careful plan to deal with any outbreak. We will use the same good epidemiological tools: quickly detecting smallpox if and when it occurs, isolating all cases and contacts, and vaccinating anyone who is likely to contract the disease. We eliminated smallpox once. We can do it again. The odds that a terrorist would ever use smallpox against us are very low. But if one does, we will be ready.
Lawrence Brilliant, M.D., author of The Management of Smallpox Eradication in India (University of Michigan), is writing a memoir.