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User-Driven Syringe Exchange is Best Model to Reduce HIV and Hepatitis C

, by Emily Newman


Photo: San Francisco AIDS Foundation

The public health benefits to syringe exchange and distribution are clear. Syringe exchanges and distribution efforts across the U.S. have curbed the spread of infectious diseases like HIV and hepatitis C and also reduce the likelihood that people who inject drugs develop other bacterial infections and poor vein health. In San Francisco, the percentage of people who used injection drugs and were infected with HIV doubled between 1986 and 1987—rising from 7% to 14%. When efforts were rolled out in the city to distribute syringes, test for HIV and educate people about how to sterilize injection equipment with bleach, the seroprevalence rate stabilized at about 12% from 1987 into the early 1990s.

But the models that govern syringe exchange and distribution—that dictate how many syringes a client can receive—make a big impact on how effective these harm reduction programs are. In other words, not all models of syringe exchange and distribution are equal, and allowing clients to choose the number of needles they receive—the “distribution approach”—has been found to be the most effective at preventing infections.

“Distribution approaches to syringe exchanges have a larger impact on reducing syringe sharing and unsafe injection practices than one-for-one exchanges, and do not result in increased unsafe discard of syringes,” said Robert Heimer, PhD, a professor of epidemiology and pharmacology and director of emerging infections program at Yale School of Public Health. “This is the policy that works best.”

The distribution model is, as Heimer described, a ‘how many do you need?’ way of distributing syringes. “If someone says they need a case [of syringes], you give them a case,” he explained. One-for-one syringe exchanges are much stricter: People can get new syringes, but only to replace the exact number that are returned. Often, one-for-one exchanges also have a cap on the number of syringes that can be accessed at one time.

One-for-one exchanges, and other policies that limit the number of syringes that people can access, were developed with the idea that fewer syringes would be improperly discarded when the number of syringes people can access is limited to the number of used syringes they return.

“This has never been shown to be true,” stated Heimer. He points to city-level data conducted in three cities across the U.S.—each with different syringe exchange/distribution policies—that compared rates of syringe return. The city with the most liberal policy—Chicago—also had the highest rate of return of syringes. “Even though they were giving away more syringes, a higher percentage of the syringes came back. Giving out more does not mean those syringes disappear into the ether. If you give more syringes away, you reduce syringe scarcity and more of them come back,” he said.

Another study conducted across 24 syringe exchange sites in California also found that greater syringe access did not increase unsafe syringe disposal. In fact, the greater the access to syringes, the more likely people are to dispose of them in safe locations.

One-for-one exchanges and other policies that limit the number of syringes that people can access at one time make it more likely that people will end up re-using, or sharing, injection drug equipment, Heimer says. Hepatitis C is especially likely to be transmitted during the drug dissolving, cooking or injecting process—the virus is even more resilient than HIV—so it’s crucial for sterile syringes to be used whenever people inject and prepare drugs, he said.

A study of syringe exchanges in San Francisco, Chicago and Baltimore conducted in the early 1990s measured syringe re-use over time to assess the impact of these fairly new exchange programs. In all three cities, the percentage of people who reported using a syringe only once before returning it increased over time. But in Chicago—the city that did not operate on a strictly one-for-one exchange—the percentage of people reporting only one injection per syringe went up dramatically (from 6.4% to 74.2%) while the two other cities saw less of an impact. (San Francisco saw a rise from 10% to 29% in the three years to 1993; Baltimore found that 3.2% of people used syringes once before accessing the exchange and 11.6% did 6 months later). In the early nineties, Chicago allowed ten syringes to be distributed for the first five returned with no limit on the total number that could be exchanged but the other two cities at that time operated on a strict one-to-one exchange. The authors speculate that, “the [Chicago] approach may increase accessibility to the point where syringes can be routinely used just once.”

Another study, conducted between 1998 and 2000, compared drug-use practices among people in Chicago, Oakland and Hartford. The study found that people in cities with more permissive syringe exchange policies that allow for greater access (Chicago and Oakland) were significantly less likely to reuse syringes than people who were only able to get syringes one-to-one with a limit capped at 10 (Hartford). People who used syringe exchange sites were also less likely to have injected drugs using someone else’s previously used syringe in Chicago (7%) and Oakland (11%) compared to Hartford (26%).

A recently published report of peer-based qualitative research done with people who inject drugs in Australia makes is clear that people prefer not to re-use syringes. “No one likes using the dirties,” the report sums. But participants were very clear that re-use did happen when restrictions were placed on the number of syringes people could access per day. “‘They tell you are only allowed six [syringes] a day, but some days I have more, might have eight or nine shots a day…they’re telling me how many shots I can have a day and that doesn’t work out,’” the report quotes one participant as saying.

“Some of the Canberra participants believed the limitations placed on injecting equipment by the NSP [Needle and Syringe Program] was directly contributing to increased HCV [hepatitis C] transmissions,” the report says.


Blumenthal, R. and others. Sterile syringe access conditions and variations in HIV risk among drug injectors in three cities. Addiction, 2004.

Blumenthal, R. and others. Higher syringe coverage is associated with lower odds of HIV risk and does not increase unsafe syringe disposal among syringe exchange program clients. Drug and Alcohol Dependency. 2007.

Duvnjak, A. and others. ‘No one likes using the dirties.’ Australian Injecting and Illicit Drug Users League. 2015.

Lurie, P. and others. The public health impact of needle exchange programs in the United States and abroad: Summary, conclusions and recommendations. 1993.

Heimer, R. and others. Syringe use and reuse: Effects of syringe exchange programs in four cities. Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology. 1998.

Watters, J. Trends in risk behavior and HIV seroprevalence in heterosexual injection drug users in San Francisco, 1986-1992. JAIDS, 1994.


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