During the tests, mice were given access to deposits of heroin over an extended period of time. Those given the vaccine showed a huge drop in heroin consumption, giving the institute hope that it could also work on people[...]
Using the immune system's ability to make an immune response against any molecule is awesome, but there are a number of potential problems with this sort of approach. In the article, a scientist is quoted as saying that this might block other opioids that are used as theraputics (like Vicodin), but I don't think it's a good idea to use opioids as pain relievers in addicts anyway. It seems to me that the real danger is that drugs like heroine work because they mimic neurotransmitters our bodies naturally make, and activating an immune response against a molecule so similar to our own might predispose people to autoimmunity. Still, it's a neat idea, and I suppose that a small increase in risk for autoimmunity might be worth it to stop a crippling addiction.