By Nell Boyce
When Charles Schuster developed a vaccine that made monkeys immune to a heroin high, he hoped the work might someday help recovering addicts. But Schuster, now at Wayne State University, wasn't prepared for what happened next. "I began to get calls and plaintive letters from parents all over the world saying please won't you immunize my child so that they won't become a heroin addict," he recalls. The idea of using a vaccine to prevent rather than just treat addiction made Schuster "leery," and he dropped the research.

That was three decades ago. Now vaccines against vice are back, thanks to biotech firms that have spent years and millions in federal grant money pursuing them. Vaccines against cocaine and nicotine have just entered clinical trials, and ethicists wonder what will happen if they work. While traditional vaccines protect against diseases that no one wants to get, vice vaccines would fight pleasures that many people cherish in spite of their dangers. The shots might appeal not just to addicts trying to break a habit but also to parents, schools, and governments, raising issues of personal choice and social benefit so knotty that the National Academy of Sciences will hold a meeting this week to consider them.

Blocking the buzz. The vaccines would work by spurring the body to create antibodies against the drug. The immune system normally ignores small molecules like nicotine or cocaine, so developers have to link the drug molecule to a larger one. Once the immune system makes antibodies to the combination, it will later recognize the naked drug, binding to it and keeping it from reaching the brain, where it would generate a high.

Biotech firms Nabi Biopharmaceuticals and Xenova have already finished initial safety studies of nicotine vaccines and are launching larger trials. In its new safety trial, Nabi will also study how its vaccine alters smokers' habits. Xenova has developed an anticocaine vaccine, which Thomas Kosten of Yale University has tested in dozens of recovering addicts. He says some who used cocaine afterward reported that it seemed less exciting.

So far, scientists haven't been able to see firsthand how the vaccines change a person's response to a drug, because it's unethical to give nicotine or cocaine to a recovering addict. Not so if the test subjects are users who don't want to quit, says John St Clair Roberts of Xenova. Last week, Xenova said it was vaccinating 10 volunteers with its anticocaine shot, then giving them the drug to see if the vaccine blocks its effect on mood, heart rate, and blood pressure.

Even if these trials pan out, it will be several years before vice vaccines hit the market. But eventually, say ethicists, institutions struggling with drug abuse, from prisons to schools, might embrace them, and healthcare workers might urge them on pregnant women. Parents also might want to get their children vaccinated as a preventive measure. Nabi's Robert Naso is upfront about the company's interest in someday marketing an antinicotine vaccine to the parents of teens. "They'll still want to smoke at a party on Saturday night and look cool," Naso says. "But hopefully it will prevent them from becoming a two-pack-a-day addicted smoker." A cocaine vaccine might hold a similar appeal. "Imagine your kid is growing up in a rough neighborhood in Baltimore, where you have drug dealers all over," says Thomas Murray, a bioethicist at the Hastings Center. "Wouldn't you be tempted?"

Xenova's St Clair Roberts says that his company currently has no plans to market its cocaine vaccine for prevention. "I see that as being a nightmare," he says. Scientists working in the field are "absolutely" aware of all the tricky social issues their new vaccines might create, adds Paul Pentel of the University of Minnesota, who has studied Nabi's antinicotine vaccine. But they also see the shots as a potentially huge boon for treating addiction.

Treatment rather than prevention is what today's vaccines would most likely be best at in any case. The vaccines raise antibodies that last only months, requiring frequent booster shots. And they don't totally block drugs' effects; higher doses could overwhelm the antibody response.

But scientists are working to make the vaccines last longer and be stronger. And they're making progress toward shots for other drugs, like PCP and methamphetamine. So while the current vaccines can't guarantee clean living, they might just represent a step toward a future when people end up as slaves to virtue, rather than vice.