A scientist at the Walter Reed Army Institute of Research is developing a vaccine designed to treat heroin addiction while at the same time prevent HIV infection. This project is one of a number of research initiatives around the world that are working toward new vaccines to fight addiction.

The National Institute on Drug Abuse recently pledged $5 million toward Dr. Gary Matyas’ work on the new dual vaccine. The goal of the vaccine is to fight heroin abuse and the high risk of HIV infection among heroin users who inject the drug.

“Heroin users have a high incidence of HIV, especially in regions of the former Soviet Union, South America and parts of Europe,” Dr. Matyas said. “If you can reduce heroin use, you can reduce the spread of HIV. That’s why we’re focusing on both heroin and HIV in one vaccine.”

The two parts of the vaccine are being developed separately, and will be combined when they have both been shown to be effective in small animals. The vaccine could be ready to be tested in nonhuman primates in several years.

The heroin component of the vaccine is in a more advanced stage, he explained. Researchers are taking small molecules that mimic heroin, and attaching them to the active component in the human tetanus vaccine. They are using a potent adjuvant formulation—a substance that enhances the immune system response. “This produces a very strong antibody response,” Dr. Matyas notes. “The antibody binds to heroin and prevents it from crossing the blood-brain barrier and producing a pleasurable effect.”

The HIV component of the vaccine is based on one that was tested in Thailand. A clinical trial of that vaccine, published in The New England Journal of Medicine in 2009, was the first HIV vaccine study to show any efficacy, Dr. Matyas said. The study found the vaccine effectiveness rate was 31.2 percent. The U.S. Military HIV Research Program, part of the Walter Reed Army Institute of Research, is working to enhance the response rate.

Once the vaccine is commercially available, it will require booster shots in addition to the initial injection, according to Dr. Matyas.

Most current addiction vaccines are focused on nicotine. Although several nicotine vaccine trials have had disappointing results, researchers continue to test nicotine vaccines. A benefit of a vaccine is that it would be given once a month, which would be easier to stick with than daily nicotine patches or gum. Researchers are studying cocaine vaccines as well.

Last year researchers in California, using a mouse model, announced they have found three new formulations that could be used in a vaccine to treat addiction to methamphetamine.