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Researchers say a fentanyl vaccine showed promise in a clinical trial involving rats. Luis Velasco/Stocksy
  • Researchers say a new vaccine shows promise in blocking fentanyl from entering a person’s brain.
  • They say the vaccine could help reduce overdoses and aid in addiction recovery.
  • Experts, however, point out that the new vaccine has only been tested on rats, so more research is needed on its effectiveness on humans.
  • They also note that people who’ve had the vaccine could switch to other opioids.

Researchers say they’ve developed a breakthrough vaccine blocking fentanyl from entering the brain and eliminating its high effect.

The researchers said the vaccine could have major implications on helping solve the nation’s opioid crisis.

The study, published in the journal Pharmaceutics, was led by the University of Houston researchers. In it, the team of scientists reports that the vaccine targets the synthetic opioid fentanyl by blocking its ability to enter the brain.

The team said opioid use disorder (OUD) is treatable, but an estimated 80% of people addicted to the drug experience a relapse after treatment

The researchers said in a statement that the vaccine “could not be timelier or more in demand.”

“Over 150 people die every day from overdoses of synthetic opioids including fentanyl, which is 50 times stronger than heroin and 100 times stronger than morphine,” the researchers said. “Consumption of about 2 milligrams of fentanyl (the size of two grains of rice) is likely to be fatal depending on a person’s size.”

The vaccine didn’t produce adverse side effects in the rats involved in lab studies, researchers said. The team plans to start clinical trials in humans soon.

“Our vaccine is able to generate anti-fentanyl antibodies that bind to the consumed fentanyl and prevent it from entering the brain, allowing it to be eliminated out of the body via the kidneys,” Colin Haile, the study’s lead author and a research associate professor of psychology at the University of Houston and a founding member of the UH Drug Discovery Institute, said in the statement. “Thus, the individual will not feel the euphoric effects and can ‘get back on the wagon’ to sobriety.”

Fentanyl is especially dangerous because it’s frequently added to street drugs such as cocaine, methamphetamine, and other opioids, such as oxycodone and hydrocodone/acetaminophen pills, and even to counterfeit benzodiazepines like Xanax.

Therefore, people who often don’t know they’re taking fentanyl can die or become addicted to it.

Dr. William Soliman is the founder and chief executive officer of the Accreditation Council for Medical Affairs. He told Healthline there’s currently nothing available comparable to the vaccine.

“It works similarly to other vaccines in that it makes antibodies that recognize a target opioid,” Soliman said. “The anti-fentanyl antibodies are specific to fentanyl and its derivatives and did not cross-react with opioids like morphine, which means that a vaccinated patient could still be treated with other opioids.”

Jay Evans, a research professor and director of the Center for Translational Medicine at the University of Montana, told Healthline the vaccine could have multiple uses.

“The vaccine could be administered to people with opioid use disorder to help them quit and not relapse while seeking treatment,” Evans said. “The vaccine could also be used to prevent overdose in people at risk of accidental or purposeful exposure to fentanyl.”

Dr. Mike Sevilla, a family physician based in Salem, Ohio., told Healthline he’s impressed by not just the vaccine’s apparent ability to prevent an addictive high, but that it could save lives after overdoses.

He added the vaccine would streamline the process of recovery for people who are addicted to fentanyl.

“In the past, medication treatment for substance abuse disorders has really relied on patients to follow a strict regimen, which can be challenging,” Sevilla said. “Access to some of these medications to treat addictions can be difficult, depending on where the person lives, their ability to get to the treatment clinic, and other social drivers of health. I believe that a vaccine to potentially treat addictions could be a game changer.”

Some experts are stopping short of calling the vaccine a breakthrough yet.

“Just because we are seeing this breakthrough through an animal-based study does not mean that its efficacy will transfer to humans,” Dr. Emil Tsai, a neuroscientist and founding chief executive officer of biotech developer SyneuRx, told Healthline. “The biological divergence between the species can lead to unreliable results in the transfer.

“That unknown aside, there are a few points within the study that I am dubious about,” Tsai said. “It’s unclear why the results were more effective for male rats than for female rats. In addition, the decision to make this drug only respond to fentanyl does little to combat those who are addicted to opioids, as this leaves the possibility for them to seek out other opioid drugs.”

Tsai said the vaccine only addresses one part of recovery.

“It’s important to treat the entire scope of the addiction,” Tsai said. “Relying on biological methods is a piecemeal solution. It does not address the entire problem. Those who are reliant on drugs or alcohol need counseling and mental wellness for healing.”

Dr. Kelly Johnson-Arbor, a medical toxicologist and director at National Capital Poison Center, told Healthline the vaccine won’t address other opioids and some people may avoid them because of the false stigma associated with vaccines.

“Boosters are also likely to be required for the fentanyl vaccine, meaning that vaccinated individuals may not have lifelong immunity to fentanyl overdose, and the duration of action, and safety, of the vaccine in humans must still be evaluated,” Johnson-Arbor said. “The need for vaccine boosters means that vaccinated individuals will need to re-engage with the healthcare system on a regular basis, which can be a challenge for some individuals with opioid use disorder.”

None of which precludes the vaccine being a good idea, Johnson-Arbor said.

“Overall, fentanyl vaccination is a promising advancement in the prevention and treatment of opioid use disorder, but it still requires more careful studies in humans as well as consideration of its acceptance in the current social and political climate of this country,” she said.