By Claire Zagorski / FilterMag

In 1974, scientists at the University of Chicago immunized a rhesus monkey against morphine. After training the monkey to self-administer both heroin and cocaine by hitting buttons that delivered small, separate doses into a surgically-placed catheter, they administered the vaccine. The monkey’s heroin use plummeted, but it continued to use cocaine the same as before—a sign that the vaccine was working.

The effects started wearing off in a matter of hours, and it wasn’t long before the monkey required boosters. If offered a high enough dose of heroin, its interest in using it returned.

This wasn’t the most sophisticated methodology. But in the decades since, as our technology and grasp of vaccine science advanced, the idea of a vaccine against addiction lingered. Researchers have attempted immunizations for tobacco and cocaine, both of which were tested on humans but failed to receive Food and Drug Administration approval because they were found no more effective than placebo.

Human trials are currently underway for a vaccine against oxycodone, oxymorphone and hydrocodone—better known as OxyContin, Opana and Vicodin. The University of Minnesota Medical School team behind the research sees this as an additional treatment option for addiction to those pharmaceuticals.

The vaccine is intended for people with opioid use disorder. It would train immune cells to treat opioid molecules like an invading pathogen, and destroy them before they can make it to the brain. It would not reduce cravings, but would block people from feeling any effects of the opioid after they used it. If effective, they would experience no pain relief; no euphoria; no overdose.