One day there might be a heroin vaccine that stops people from becoming addicted to the opioid drug and prevents overdose.

Scientists took a step in that direction when they designed a new drug that has shown promise in mice, offering the immunized animals “significant protection from lethal heroin doses,” according to a study in the journal Molecular Pharmaceutics. It works by stimulating antibodies to act against heroin and stop the drug from affecting the brain.

A protein in the vaccine sounds the alarm to the immune system so it fights off the heroin molecule, which would have otherwise slid under the radar.

If the drug user can no longer get high, the recovering addict may avoid relapsing, the researchers say.

Relapsing comes with a high overdose risk for heroin addicts because their tolerance level changes during the time they are clean.

“We believe that a heroin vaccine would be tremendously beneficial for people who have a heroin substance use disorder but have found difficulty in trying to quit,” first study author Candy Hwang said in a statement from the Scripps Research Institute.

The study describes how the researchers looked through different vaccine structures, with varying proteins, to find the one that was effective and could be stored at room temperature. The one they chose works in both a liquid and powder form.

“Our goal was to prepare a vaccine that could be advanced to clinical trials,” according to Hwang. “The heroin vaccine is one step closer to clinical evaluation.”

If the vaccine works on humans, it could potentially save the thousands of people who die in the United States from heroin overdoses every year and offer relief to those who are struggling with opioid addiction.

In 2016, heroin was the second-leading cause of American overdose deaths, after synthetic opioids like fentanyl, according to statistics from the U.S. National Institute on Drug Abuse. Almost 15,500 people died of heroin overdoses that year, a number that represents a dramatic increase in just the last few years.

Although there is no vaccine yet, there is help for people who are experiencing an overdose. The drug naloxone, also known by its brand name Narcan, can be injected into or administered as a nasal spray to an opioid overdose victim. The drug attaches to the brain’s opioid receptors to block the effects of whichever drug the victim has taken.

naloxone-narcan-intranasal The drug naloxone can be used to rescue people overdosing on opioids and is available to the public. Photo: Elana Glowatz