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Virginia Tech researchers are advancing a new generation of vaccines designed to block opioids from reaching the brain and triggering their addictive effects. It is hoped this work could help prevent overdose deaths that now exceed 100,000 each year in the U.S.
In a new study the researchers report that a novel hybrid lipid-polymer nanoparticle vaccine produced stronger immune responses and improved protection against oxycodone in mice.
The scientists also found that pairing a similar fentanyl-targeting vaccine with an immune-boosting adjuvant restored its effectiveness, offering a blueprint for vaccines aimed at curbing opioid use disorder and preventing overdose. Consequently, the research group are developing targeted vaccines against opioids such as oxycodone and fentanyl.
Blocking opioid effects
Specifically, the scientists have created a delivery mechanism that uses biodegradable nanoparticles that mimic viruses in size and structure. These particles are coated with opioid molecules — such as oxycodone or fentanyl — so the immune system recognizes them as a threat. This virus-like structure enhances the vaccine’s ability to trigger a strong and lasting immune response.
This means the researchers are seeking to develop a medicine where the body recognises the drug as a threat and mounts a defence.
This is achieved by stimulating the body’s immune system to produce opioid-attacking antibodies, it prevents opioids in the user’s system from crossing the blood-brain barrier, thereby blocking the euphoric effects typically associated with their use.
Early results suggest antibody levels remain effective for several months, and the researchers hope subsequent optimization could extend protection to a full year.
The vaccine is also designed to be highly specific, targeting only the intended opioid molecule without interfering with other pain medications. This precision ensures that patients can still receive any necessary clinical treatments without compromising the vaccine’s protective effects.
Curbing future addictions
While the vaccine is not intended for general use like a flu shot is, it could be administered to individuals with opioid use disorder or those at high risk of exposure. In particular, the researchers hope the vaccine could serve as a deterrent for first-time users and at-risk youths.
While the vaccine does not stop a user from using drugs, the hope is that it will curb the need to use, reducing accidental overdose and providing a safe way for individuals who have opioid use disorder to become less reliant on drugs.
Beyond individual patients, the vaccine could benefit families, communities, and health care systems.
The research appears in the Journal of Controlled Release, titled “Innate immune mechanisms underlying the efficacy of a next-generation nanoparticle-based vaccine against opioid use disorders.”