In the days following the terrorist attacks that brought down the World Trade Center and demolished part of the Pentagon, I received a series of e-mails from my sister asking what I thought she could do to protect herself and her family. Should she stock up on water? On food? What about buying a gas mask? I told her I doubted that any of those things would really help. At first blush the notion of suburban moms buying gas masks seemed a little silly. But a lot of people were buying gas masks at that point, and mostly they were not silly people, and the impulse they were acting on was not silly. What they wanted was to do something: to exert at least a little control over a new and frightening situation. That is just the sort of impulse that the fight against terrorism needs to put to use. One way to use it is against the threat of smallpox.
Experts have agreed that smallpox terrorism is potentially the Big One. Maybe not bigger in terms of lives lost than, say, a nuclear warhead detonating over Manhattan, but certainly right up there, and probably more socially destabilizing. Unlike chemical agents and some other biological agents, such as anthrax (as we've lately seen) and botulism, smallpox spreads virulently from person to person. The disease is fatal 30 percent of the time and leaves its survivors disfigured and sometimes blind. Symptoms take a week or two to appear. In an urbanized country full of planes, trains, and automobiles, smallpox could easily spread to any number of cities and states before health officials realized what was going on.
Routine smallpox vaccination ended in the early 1970s, because a worldwide campaign had succeeded in eradicating the disease. The virus survived only in laboratories in the United States and the Soviet Union. After the Soviet Union collapsed, credible reports surfaced alleging that the Soviets had produced smallpox in large quantities, for biological warfare. Bio-terrorism experts began to worry that the Russians might have let the virus slip into the wrong hands. Still, most people believed that smallpox's very virulence made it an unlikely weapon of terror. After September 11 a lot of those people changed their minds.
I was vaccinated for smallpox years ago, in childhood; so were many other Americans who are now over thirty. But it's unclear how much good this would do if smallpox were unleashed today. "One of the problems with smallpox vaccine is that immunity doesn't last very long," Peter J. Hotez, a senior fellow at the Sabin Vaccine Institute, in Washington, D.C., told me when I asked if I would be safe. "It can last as few as three to five years." And younger people, of course, weren't vaccinated. America today would be a tinderbox for smallpox: something like 90 percent of the population is thought to be susceptible.
To its credit, the Clinton Administration took the threat seriously. Realizing that existing stocks (about 12 million to 15 million doses of twenty-year-old vaccine) were too thin to cope with a serious crisis, in September of last year the government ordered up a new smallpox vaccine, with the first 40 million doses to be delivered in 2004 and more to come thereafter. This October, as anthrax scares transformed the threat of bio-terrorism into reality, the Bush Administration announced that it would seek to increase the smallpox-vaccine inventory to 300 million doses, possibly by next year.
With the new vaccine will come a new and difficult question: Who should be vaccinated? My first thought was "Everyone." Or at least—as Homeland Security Chief Tom Ridge has suggested—we should resume routine vaccination of children. But this sort of uniform approach has a significant drawback. The smallpox vaccine is not perfectly safe. During the eradication campaign, according to Tara O'Toole, of the Johns Hopkins School of Public Health, about one in 300,000 people died from side effects of the vaccine or suffered irreversible brain damage. At that rate, if all 280 million Americans were to be vaccinated, nearly a thousand people would die or be gravely injured.
For that reason the government instead built its plans around a containment strategy. Vaccine would be stockpiled for use in case of an outbreak. If smallpox were spotted, authorities would declare a health emergency and rush to vaccinate (or quarantine) everyone likely to have crossed the virus's path. (Fortunately, the vaccine is effective even when given a few days after exposure, so in principle post-outbreak vaccination could stop the spread.) There is certainly something to be said for the containment strategy, but it is not without worrisome risks. It relies on health workers, public officials, and the public itself to react quickly, calmly, and efficiently. Virtually everyone who was exposed would need to be promptly vaccinated or quarantined. That would be easier said than done, because the early symptoms of smallpox look like flu. Moreover, once word of a smallpox outbreak hit the street, panic, chaos, flight, and human error would inevitably give the virus chances to spread. Even if a containment plan ran like clockwork, some people—those caught at the onset—would die who might have lived had they previously been vaccinated.