Heroin Vaccine Blocks Drug High in Tests on Monkeys

A vaccine designed to block a heroin "high" worked in monkeys, which could open the door to human clinical trials, researchers say.This is the first vaccine against an opioid proved to be effective at this stage of testing, according to the development team at The Scripps Research Institute in La Jolla, Calif.The vaccine already worked in rodents.For the new trial, four rhesus monkeys given three doses of the vaccine had an effective immune response that neutralized varying doses of heroin. The effect was strongest in the first month but lasted more than eight months after vaccination. It caused no adverse side effects, according to the researchers.