Over the past 20 years, the use of opioids has risen sharply in the United States, causing an increase in opioid use disorder and opioid overdose. These include prescription opioids, such as oxycodone, as well as illegally manufactured fentanyl or heroin.

This public health emergency is often referred to as the opioid crisis.

The COVID-19 pandemic has exacerbated this crisis. According to the National Institute on Drug Abuse (NIDA), opioids were involved in 68,630 overdose deaths in 2020 compared to 49,860 in 2019. That’s a 38 percent increase.

Opioids are powerful painkillers that can cause you to feel happy and relaxed. Although there are highly effective treatments available for opioid use disorder, like methadone, buprenorphine, and naltrexone, some people may seek other options.

Opioid vaccines are a new treatment currently in development. At the clinical trial stage, they help the immune system produce antibodies that target and prevent opioid molecules from entering the brain.

This article explores how these new vaccines work, what stage research is at, and what the impact might be.

When scientists developed the first vaccines midway through the 20th century, they revolutionized public health practice by preventing the spread of contagious illnesses, like polio, smallpox, and diphtheria.

Vaccines work by introducing a small amount of a pathogen into the body so that the immune system can create antibodies. Once the immune system has developed antibodies, it’s ready to fight future infections.

Vaccines are not 100 percent effective, but most can drastically reduce your chances of developing a severe illness. They have also helped get rid of life threatening diseases around the world by preventing their spread.

Today, vaccines are still widely used, with the COVID-19 vaccine being the most obvious example. Hundreds of other vaccines are currently in development, many of which target non-transmissible health conditions, like cancer, diabetes, and substance use disorders.

The possibility of using a vaccine to prevent addiction isn’t new. But in recent years, the opioid crisis has led to an increase in funding for research into a vaccine to treat opioid use disorder.

An opioid vaccine would work similarly to traditional vaccines by stimulating the immune system to produce antibodies that could bind to opioid molecules before they reach receptors in your spinal cord or brain.

One of the key differences is that opioid molecules are very small. Although they are foreign substances, the immune system doesn’t usually flag them as threats.

To achieve this, opioid vaccines include three key components:

  • Hapten. This is a molecule that is chemically similar to the opioid in question.
  • Immunogenic carrier. This is a protein that binds to haptens.
  • Adjuvants. These are substances that boost the immune system’s response.

Together, the haptens and immunogenic carriers are large enough for the immune system to identify them as a threat. This triggers the production of antibodies.

How is a vaccine different from naltrexone?

Naltrexone is an FDA-approved medication used to treat alcohol and opioid use disorders. When used to treat the latter, it is given in the form of a long-acting injection called Vivitrol.

It’s different from a vaccine, which uses your immune system to develop antibodies that target opioids in your bloodstream. Naltrexone works by binding to opioid receptors, preventing opioids from binding to them and blocking their effects.

If you take opioids after receiving an injection, you won’t experience a high. Naltrexone also reduces drug cravings.

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Developing safe and effective medical treatments can take years, and some treatments don’t ever receive FDA approval. While the opioid crisis has made the need for novel treatments for opioid use disorder increasingly urgent, we’re still years away from a vaccine.

Most opioid vaccines are in preclinical trials and have yet to be tested on humans. According to a 2019 review, several vaccines targeting common opioids have shown promise in animal studies.

For example, a 2017 animal study assessed the safety and effectiveness of a vaccine for opioid use disorder involving oxycodone.

The authors reported that the vaccine protected against opioid use disorder and overdose. It could also be used alongside medications like morphine, naltrexone, and naloxone in rats.

A 2018 animal study evaluated the effectiveness of various adjuvants in an anti-heroin vaccine in mice. The researchers found that a toll-like receptor 9 (TLR9+) agonist adjuvant provided significant protection from lethal doses of heroin in mice.

A more recent animal study from 2021 analyzed the effectiveness of a vaccine for carfentanil and fentanyl in mice. The authors reported that mice who received the vaccine were protected against opioid-induced respiratory depression, the main cause of overdose.

A significant limitation of the three studies described above is that their results cannot be applied to humans.

As of 2022, only one opioid vaccine has made it to human clinical trials. The clinical trial, which is ongoing at the New York State Psychiatric Institution, is designed to evaluate the safety and effectiveness of an oxycodone vaccine.

An opioid vaccine would be a novel strategy in the treatment of opioid use disorder. After vaccination, in theory, you could take opioids without experiencing a high. Getting the vaccine could significantly reduce the risk of opioid use disorder and overdose.

Vaccines have certain advantages over other treatments. They:

  • can be used prior to detox
  • can be used alongside other opioids for pain or substance use disorders treatment
  • don’t carry a risk of misuse

In addition, an opioid vaccine might be effective for 6 to 12 months, providing longer protection than current treatments.

Opioid use disorder is a complex illness that doesn’t have a simple, one-size-fits-all solution. While opioid vaccines present a unique opportunity, they’re likely not going to eradicate addiction.

Vaccines depend on an immune system response, which can vary from person to person. They will likely be most effective when used alongside other proven treatments, like medication and behavioral therapy.

Treating opioid use disorder

If you are living with opioid use disorder, there is help available. The first step is talking with someone you trust, whether a family member, friend, or healthcare professional, about what you are experiencing.

Your doctor can provide you with more information about medications for opioid use disorder. They can also refer you to healthcare services and professionals that specialize in addiction treatment.

To learn more about the resources available in your area, call the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 800-662-4357. All calls to the helpline, which is open 24/7, are free of charge and confidential.

Additionally, SAMHSA’s Behavioral Health Treatment Services Locator can help you find therapy or group counseling for addiction.

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Opioid vaccines are a potential treatment for opioid use disorder. They work by training the immune system to recognize opioid molecules as a threat and prevent them from binding to receptors.

In theory, opioid vaccines would prevent the effects of opioids, reducing the risk of addiction and overdose. They could be used alongside other medications and therapies for opioid use disorder.

Although there are several opioid vaccines currently in development, most have not yet been tested on humans. Vaccines that make it past the preclinical phase will undergo clinical trials in the coming years.

To learn more about ongoing clinical trials, visit the U.S. National Library of Medicine’s Clinical Trials database or talk with a healthcare professional.