Chicago area experts express concerns about overdose and other potential problems from a vaccine to immunize addicts against the pleasures of cocaine.

With the release of a Phase 1 study reporting that an injection can block the "high" of cocaine, researchers at Yale and Baylor universities may be paving the way to an anti-addiction vaccine.

Excitement surrounds the announcement, involving an addiction that accounts for 31 percent of drug-related emergency room visits a year and often sends its users into cardiac arrest.

"The vaccine is very safe and we did not observe any major side effects," stated Dr. Thomas Kosten, principal investigator of the study.

But concerns about the vaccine include the dangers of overdose to offset the suppressed feelings of pleasure. More broadly, doctors are worried the vaccine is not a cure to the problem, but a supposed quick fix.

“It makes no common sense to approach an addiction problem, especially to cocaine, whereby you block its users from feeling its effects,” said Dr. Andy Maniotis, professor of Bioengineering at the University of Illinois at Chicago.

The study, released online this month ahead of publication in the Archives of General Psychiatry, reported a double-blind, placebo-controlled Phase 1 trial in which subjects were divided into three groups of cocaine users.

One group received a high dose of the vaccine, another received a low dose and a final group received a placebo. Researchers observed an overall decrease in cocaine use, but only 38 percent of the heavy dose group actually experienced an interference with their cocaine-euphoria. The vaccine required five injections and the effects of the boosters tapered off over time – meaning that continued vaccine would be necessary. 

Many study participants used more cocaine than normal in the course of the study to override the “immunity,” according to the study. This is one piece of evidence that the vaccine is still in the beginning stages of development, said Dr. Stephen Dinwiddie of the University of Chicago, department of psychiatry and behavioral neuroscience.

“This vaccine is very exciting in terms of proof that this kind of strategy really looks promising. It’s the beginning of the story, not the end,” Dinwiddie said. “It’s going to be a long time before we can translate this to a technique that will have significant public health benefits. “

However, Dinwiddie is hopeful this will be an effective and perhaps more accessible way to deal with what is a serious public health issue without many promising advances in the past two decades.

“The mainstay of [drug addiction] treatment has been behavioral rather than medication and a great deal of effort has been devoted to trying to improve behavioral interventions with some success – but they are very labor intensive, they are not available to many many people,” Dinwiddie said.

He said he worries, though, that the potential for affordability might make the vaccine the preferred treatment, even if it’s not the most effective.

“We have treatments that work, but they are underfunded and not available to many people. If a vaccine is cheap – then it might be used more mainstream even if it’s not as good,” Dinwiddie said.

For Dr. Mayer Eisenstein, medical director of Home First Health Services, the will to quit paired with available paths to recovery such as soliciting help from family, friends or counselors can be effective and should not be discounted. He said the problem with the vaccination approach is overreaching and telling.

“We don’t want to address the real issue. If you’re taking drugs, you’ve got problems,” he said. “I don’t care what’s in the vaccine – it’s not going to cure an addiction. There’s no magic bullet in life.”

Kosten stated the vaccine, TA-CD, would need to be combined with behavioral therapy for successful treatment of addiction.