Imagine a vaccine against smoking: People trying to quit would light up a cigarette and feel nothing. Or a vaccine against cocaine, one that would prevent addicts from enjoying the drug’s high.

Though neither is imminent, both are on the drawing board, as are vaccines to combat other addictions. While scientists have historically focused their vaccination efforts on diseases like polio, smallpox and diphtheria — with great success — they are now at work on shots that could one day release people from the grip of substance abuse.

“Just like with nicotine patches and the gum, those things are just systems to get people off the drugs,” said Dr Kim D. Janda, a professor at the Scripps Research Institute who has made this his life’s work.

Janda, a gruff-talking chemist, has been trying for more than 25 years to create such a vaccine. Like shots against disease, these vaccines would work by spurring the immune system to produce antibodies that would shut down the narcotic before it could take root in the body, or the brain.

Unlike preventive vaccines — like the ones for mumps, measles and so on — this type would be administered after someone had already succumbed to an addiction. For instance cocaine addicts who had been vaccinated with one of Janda’s formulations before they snorted cocaine reported feeling like they’d used “dirty coke,” he said. “They felt like they were wasting their money.”

It’s a novel use for vaccines that has placed Janda, who is 54, in the vanguard of addiction treatment. Because addiction is now thought to cause physical changes in the brain, doctors increasingly advocate medical solutions to drug problems, leading to renewed interest in his work.

In July, Janda’s lab — 25 researchers, most of graduate-school age — made headlines when it announced that it had produced a vaccine that blunted the effects of heroin in rats. Rodents given the vaccine didn’t experience the pain-deadening effects of heroin and stopped helping themselves to the drug, presumably because it ceased to have any effect.

But the breakthrough came on the heels of a setback: a phase two clinical trial for a nicotine vaccine that was based largely on his work was declared a failure this summer when people receiving the drug quit smoking at the same rate as people receiving a placebo.

To this day, despite many promising breakthroughs, not one of Janda’s vaccines has won approval from the Food and Drug Administration. For despite many successes in the lab — including promising animal tests — the vaccines have yet to produce consistent results in humans during clinical trials.

The scientific principle behind Janda’s vaccines is “simplistically stupid”. They introduce a small amount of the foreign substance into the blood, causing the immune system to create antibodies that will attack that substance the next time it appears.

The difficulty is that molecules like cocaine, nicotine and methamphetamine are tiny — much smaller than disease molecules — so the immune system tends to ignore them. To overcome that Janda attaches a hapten — a bit of the drug — to a larger protein that acts as a platform. The last part of the vaccine is an adjuvant, a chemical cocktail that attracts the immune system’s notice, effectively tricking it into making antibodies against a substance it usually wouldn’t see.

Despite the disappointments, some scientists predict that Janda will succeed. No less an addiction expert than Dr Nora Volkow, director of the National Institute on Drug Abuse, calls him a “visionary” who saw the opportunity to treat addiction with medicine decades before most. Indeed, one reason that her institute is a chief source of Janda’s financing is Volkow’s belief that his work will eventually produce a marketable vaccine.

Today, scientists who are working to create vaccines against narcotics include Dr Thomas Kosten at the Baylor College of Medicine and Dr S. Michael Owens at the University of Arkansas. Kosten has had limited success with a cocaine vaccine, while Owens is focused on vaccines for methamphetamines.

All three researchers say they are hobbled by a lack of interest — read: financing — from pharmaceutical companies in vaccines for any drug other than nicotine, presumably because there is little money to be made in a shot given once every six months, and because such companies aren’t eager to associate their brands with drug addicts.

Janda is quick to caution that taking away someone’s ability to get high off of one drug hardly cures them of their addiction problems. There’s nothing to stop a vaccinated cocaine addict, for example, from turning to methamphetamines.

Like any anti-addiction treatment, his vaccines are simply meant as “a crutch for people wanting to go into abstinence,” Janda said.

“Before a parent takes a kid into college, can she take him in for a round of vaccines against all drugs?” asked Jenny Treweek, a researcher at Janda Laboratories who is working on a vaccine for Rohypnol, otherwise known as the date-rape drug. “Some teenagers might have a real problem with that.”

It’s questions like that — and the desire to solve the molecular puzzle he’s set up for himself — that motivate Janda to spend seven days a week in his lab. He spends much of that time tweaking the components of his vaccines — trying different proteins or haptens, adjusting the adjuvants — hoping to hit precisely the right formula.

But with nearly 30 years of tweaking already under his belt, he seems increasingly resigned to the idea that it might not be him who eventually moves it across the finish line.

“I figure I have eight or 10 years left,” he said. “If something doesn’t go in eight or 10 more years, then it’s someone else’s turn.”