In his California laboratory, Kim Janda is amazed by the amount of heroin he can give to rats without killing them.

Janda has created a vaccine that makes rodents immune to huge amounts of the drug and reduces the animals' urge to relapse into the dark hole of heroin addiction - a place all too familiar to a growing number of Americans.

It is a ray of promise in the battle against opiate addiction. Drug overdose deaths - fueled primarily by prescription painkillers and heroin - have tripled in the United States over the last three decades, according to the Centers for Disease Control and Prevention.

[continues 2941 words]