Suppose you could get some shots that dramatically reduce the potency of cocaine in your system through an immune system response to it? It is the sort of thing that might make it much easier for a cocaine addict to quit.
In mouse models, such a "cocaine vaccine" seems to be effective. Vaccinated mice have a far less pronounced response to comparable doses of cocaine than unvaccinated mice.
Methadone is a drug sometimes used to ween addicts off their drug addictions, but the need for fairly precise timing and dosing of a methadone therapy have been one of the important factors in a dramatic increase in accidental drug overdose deaths over the last decade or two. A vaccine treatment doesn't pose those kinds of risks.
Also, once someone received a cocaine vaccination, it would be unnecessary to monitor this part of the drug treatment program in an intensive way.
Research into similar treatments for heroin addicts and meth addicts is also underway.
Of course, there are all sorts of questions about how a mouse model translates into a human therapy. For example, the same vaccine that mutes cocaine response might actually be broader and also mute responses to medicinally useful painkillers or stimulants. Or, it might not be long lasting enough, or potent enough to deal with a heavy addiction. In the mouse model, the treatment effectively reduced drug doses by 60%. But, a human might simply increase the dose proportionately and continue the addiction.
Also, the mice were vaccinated before any exposure to cocaine, but this kind of treatment makes no sense for the general population even if the side effects and risks are pretty modest. It is hard to tell if the effect would be the same once the epigenetic changes that drug addiction causes were already in place.
Still, the prospect of a simple drug that once administered would cure people of drug addictions without long painful withdrawal and therapy, probably with relapses in most cases, at least temporarily, is a tempting possibility. And, given the negative health consequences and life consequences of being a drug addict to cocaine, heroin or meth, even significant negative side effects from the treatment would be an improvement if the vaccine is effective for people who have already become addicted. Indeed, it might even make since, pre-emptively, in people who have a strong family history of addiction and live in an environment that put them at high risk of becoming addicts themselves.