The vaccine works similar to vaccines for microorganisms, training your body to view cocaine as a bad invader. The shots, which include a cocainelike substance (succinylnorcocaine), encourage the body to pump out antibodies against cocaine. The antibodies bind to the coke, which prevents it from getting into the brain, and theoretically prevents people from getting high. Right now, only about 38 percent of the subjects who got the vaccine produced high levels of antibodies, so there's room for improvement.