Scientists are reporting development and successful initial laboratory tests on the key ingredient（原料，要素） for a much-needed vaccine¹ to help individuals addicted² to heroin³ abstain⁴ from（放弃，戒绝） the illicit⁵ drug. Their study appears in ACS' Journal of Medicinal Chemistry. Kim D. Janda and colleagues note that heroin use cost the United States more than $22 billion in 1996 annually⁶ due to medical and law enforcement expenses and productivity loss. Although behavioral therapy and certain medicines help heroin-addicted patients, many experience relapse（复发） , lack access to treatment, or develop unwanted side effects from the treatments themselves. To overcome these challenges, the researchers made and tested a new vaccine formulation that might serve as an additional tool in helping⁷ addicts⁸ maintain abstinence（节欲） . Janda's team previously⁹ reported development of vaccines¹⁰ for cocaine¹¹, methamphetamine, and nicotine¹².

Thus with laboratory rats that were given the vaccine they showed less willingness to self-administer heroin and other signs of its effectiveness. The report explains why the potential new vaccine is an improvement over previous experimental vaccines. "In conclusion, a vaccine for heroin addiction¹³ could prove to be a useful tool for combating heroin addiction, wherein it exploits a motivated recovering addict's own immune system to blunt（使迟钝） heroin's psychoactive（影响心理状态的） effects in the case of relapse," the researchers say.