Methamphetamine is one of the most addictive and thus commonly-used street drugs – according to the United Nations Office on Drugs and Crime, there are currently nearly 25 million meth addicts worldwide. Help may be on the way, however. Scientists from The Scripps Research Institute have had success in using a methamphetamine vaccine to block the effects on meth on lab rats.

The vaccine works by allowing the body’s immune system to attack methamphetamine molecules in the bloodstream, keeping them from entering the nervous system. This keeps the meth from affecting the user’s brain, and thus removes the incentive for using the drug.

Ordinarily, meth molecules are too small to evoke an antibody response from the body. The vaccine, known as M6, gets around this by linking a meth-related chemical to a larger carrier molecule that does cause an antibody response. Once the antibodies are in the bloodstream, they attack both the carrier molecules and the actual meth molecules.

In tests on rats, M6 blocked two of the typical effects of the drug – loss of the ability to regulate body temperature, and in increase in physical activity. In another ongoing Scripps study, meth-targeting antibodies were grown in cultured cells in a lab, then injected into rats in a concentrated dose. This approach also blocked the effects of the drug.

More animal trials are planned for now, with the possibility of human trials occurring in the future.