Vax Populi

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.”

Despite the vaccine’s merits and the status of anthrax on the DOD threat list, only about 24,000 doses—enough to immunize 4,000 people for one year—exist. Against the backdrop of the Sept. 11 attacks, the nation badly needs the existing anthrax vaccine and to improve it. And the government should think seriously about vaccinating the entire population.

We flock to the doctors for vaccines when we fear a disease. But when a disease is invisible, people become cavalier, even antagonistic, toward these most powerful of medical preventives. In the last decade, when vaccines have largely vanquished diseases like polio and diphtheria, an anti-vaccine lobby steadily has grown. And this thinking has spread to influence perceptions about the anthrax vaccine.

The anthrax vaccine, given to 150,000 troops during the Gulf War, became a prime suspect in the hunt for the cause of Gulf War illness, but the vaccine was completely exonerated by the U.S. Centers for Disease Control and Prevention. When DOD announced in December 1997 a mandatory anthrax vaccination program, shrill protests erupted in Congress, in the courts, and on Web sites, many of which raised dubious arguments about the vaccine’s safety. The CDC found that between 1990 and 2000, more than 1.8 million doses of the anthrax vaccine were distributed in the United States and a mere 1,544 people reported adverse events (0.08 percent). Only 5 percent of this 0.08 percent were deemed “serious” and more than half involved complaints about sore arms and the like. This compares neatly with the analysis of the chicken pox vaccine now in use. (There are other reasons the vaccine isn’t trusted, but they don’t have much to do with medicine. Click here for more.)

Without question, the current anthrax vaccine could stand some improvements, especially if its use extends beyond our fighting troops, who face a higher risk of exposure than the general population. A serious limitation of BioPort’s vaccine is that it requires six shots and annual booster inoculations. The vaccine also causes more sore arms than necessary. Plotkin says he’d like to see a new-generation anthrax vaccine made from genetically engineered proteins of the bacteria, a purer preparation than the current one that should, theoretically, be more potent and have fewer side effects. It would help, too, if researchers assessed the ability of vaccines to protect against many strains of anthrax, as an analysis of the Sverdlovsk outbreak underscored.

March 2002 will bring a definitive report on the safety and efficacy of the current vaccine. Around the same time, BioPort hopes to win FDA licensing of its new manufacturing facility and to crank up production again. If the report blesses the vaccine and BioPort starts shipping FDA-approved vials of the product, our military soon will have a promising way to protect troops from anthrax weapons. The CDC also smartly contracted last year with a company to produce a new smallpox vaccine (which now is in short supply), and the Department of Defense over the past five years has ramped up a serious research program to develop vaccines against many other biological threats.

But developing what the Department of Defense calls “countermeasures to unconventional pathogens” only makes sense if the vaccines are used. In the light of Sept. 11, we should make the anthrax vaccine available to any American who wants it and aggressively assess our other biowar vulnerabilities. Alternatively, we can cling to the comforting notion that it can’t happen here.