A viable anthrax vaccine exists. Why aren't we making it and other defensive vaccines available to the public?

Imagine if scientists had discovered a device that, with a reliable degree of certainty, could identify hijackers who planned to fly jetliners into large, densely occupied buildings. Now imagine that we did not develop this device because no commercial market existed for it, the people who screen passengers had misgivings about it, and the one manufacturer subsidized by the government to make it kept experiencing quality control problems with federal regulators.

Just such a situation now exists with a vaccine that can stop anthrax, the highly lethal bacteria that, in the chilling words of the U.S. Department of Defense, is "readily weaponized." Saddam Hussein in fact stockpiled warheads armed with anthrax spores in the mid-'90s, and the Soviet Union once manufactured the contagion in huge quantities. And because on Sept. 11 a terror war on U.S. soil crossed the line from theory to reality, an attack with weaponized anthrax seems more plausible than ever before.

Anthrax spores could kill up to 3 million people if terrorists aerosolized 100 kilograms of the bug near a major metropolis. No one would see the anthrax spores or taste them. The wind could carry the spores for several miles, and they could penetrate locked doors and closed windows. They could survive in the soil for decades.

The first symptoms would look like the flu, so no immediate alarms would ring in public health quarters. Little surprise, then, that anthrax "tops the DOD threat list," according to a report issued last March by the Army's surgeon general.

The human vaccine that protects against anthrax was licensed by the Food and Drug Administration in 1970 and has proved safe and effective in human and animal studies. True enough, the vaccine's sole manufacturer, BioPort Corp. of Lansing, Mich., has drawn deserved fire from the FDA for manufacturing irregularities. Yes, the vaccine has shortcomings. And yes, only thin evidence exists that the vaccine works in humans against "inhalation anthrax"—the deadliest form of the disease and the one that terrorists are most likely to unleash. But with U.S. civilians targeted in a terror war that promises to last as long as the Cold War and homeland defense rising to Cabinet rank, the benefits of producing and refining vaccines that would ward off bioweapons far outweigh the risks.

The BioPort vaccine's history can be traced back to the post-World War II era, when scientists at the now defunct U.S. Army Chemical Corps at Fort Detrick designed an anthrax vaccine after surmising that anthrax would make a powerful bioweapon. Tests on 600 "scientific personnel" at Fort Detrick demonstrated the vaccine's safety, and between 1955 and 1959 non-military researchers tested the efficacy of the vaccine on workers at four U.S. factories where anthrax-contaminated raw goat hair was handled. Typically, about 1 in 100 workers each year developed "cutaneous" anthrax, a less severe form of the disease that causes skin lesions. But the study, the only human efficacy trial of the vaccine, proved it 92.5 percent effective in preventing cutaneous anthrax.

The study did not directly address the much less common inhalation anthrax. But as chance would have it, an inhalation anthrax epidemic at one of the mills led the researchers to vaccinate everyone at the site. None of the vaccinated developed inhalation anthrax—good news but not scientifically relevant. (The only scientifically relevant information reaped about inhalation anthrax was a detailed ticktock about how it progressed in humans. See this sidebar for more.)

The BioPort vaccine is essentially identical to the Army product. Immunologist Tom Waytes, an official at BioPort, says the evidence of efficacy against inhalation anthrax is as convincing as possible. "You can't do traditional efficacy studies with bioweapons," he says, stressing that in monkey and rabbit studies vaccinated animals survive more than 95 percent of the time. "That's really the best you can do."

Stanley Plotkin, a leading authority on vaccines and co-author of the 1962 report on the vaccine's efficacy trial, once thought it would be too difficult to make the disease into a viable weapon. Not so anymore. "I've done a 180 degree turn, especially after [Sept. 11]. The possibility of being attacked by anthrax spores is a real one." He also notes the infamous 1979 outbreak of inhalation anthrax in Sverdlovsk, where the Soviets' bioweapons facility accidentally released spores, killing at least 66 people.

Plotkin says scientists could, with relative ease, improve the vaccine. Still, he says, "you could probably do quite well with the vaccine we have, judging from experiments in animals and the human study we did."