Research shows needle programs cut HIV rates
Research shows needle programs cut HIV rates
Studies dispel fears associated with programs
Researchers are continuing to build a strong consensus that needle-exchange programs reduce HIV infection rates among injection drug users without increasing any of the feared social problems that accompany drug use.
Since its launch in 1994, the Baltimore Needle Exchange Study has been evaluating the short-term and long-term effects of needle-exchange programs on the incidence of HIV and hepatitis C. The study’s investigators also have studied whether needle-exchange programs increase crime, increase discarded needles on the street, send bad messages to youths, or create a social space where drug users can mingle and increase their network of addicts, says Steffanie Strathdee, PhD, associate professor of epidemiology at Johns Hopkins School of Public Health in Baltimore.
"Our study in Baltimore has addressed each one of those issues, and we have an article on each one of them, and there’s absolutely no evidence that needle-exchange programs promote any of these negative consequences," Strathdee says.
One of the project’s latest published studies dispels the theory that needle-exchange programs serve as a social network for drug users. It just doesn’t happen that way, Strathdee says. "Most of the people who are meeting with other drug users and sharing needles with them have met them on the street or in shooting galleries or through informal networks," she explains. "They didn’t meet them through needle-exchange programs."
Johns Hopkins investigators interviewed more than 400 participants in a Baltimore needle-exchange program, offered them HIV testing, and then interviewed them a second time six months later. Researchers found that only 8% of the people interviewed said they had made contacts at the needle-exchange program.
Needle exchanges prove beneficial in NYC
Another recent study suggests that needle-exchange programs in New York City were a contributing factor in the decline of new HIV infections.
The prevalence rate of HIV infection among the city’s injection drug users (IDUs) was 50% in 1991, a year before needle-exchange programs received legal approval, says Don C. Des Jarlais, PhD, director of research for the Chemical Dependency Institute of Beth Israel Medical Center in New York City. That prevalence rate dropped to 30% by 1997.
"We also published another study this year where we looked at the rate of new infections. That rate went from 4% per year during the 1980s down to 1% per year in the 1992-on period," Des Jarlais says. "During the 1980s, the rate of new infections was enough to counter the deaths to AIDS, but now we’ve seen the rate of new infections going down pretty dramatically."
Needle-exchange programs, which were greatly expanded after 1992, clearly contributed to the decline of new HIV infections, Des Jarlais says. Des Jarlais and colleagues also plan to publish a paper showing that people who use needle-exchange programs are much less likely to share needles and engage in other behavior that would put them at risk for HIV.
"I think the basic conclusions are that it is possible to greatly reduce HIV transmission among drug injectors and that good access to sterile equipment is a necessary part of public health efforts to control HIV infection," Des Jarlais says.
Still other research, from RAND of Santa Monica, CA, shows that high-risk IDUs who enroll in a needle-exchange program are 2.68 times more likely to quit sharing needles than IDUs who do not use a needle-exchange program.
While these and other U.S. studies continue to show a decline in shared needle use and HIV infection among IDUs who use needle-exchange programs, some critics of such programs point to two Canadian studies that appeared to show the opposite effect.
A 1996 study in Montreal, Quebec, and a 1997 study in Vancouver, British Columbia, found that addicts who participated in needle exchanges were more than twice as likely to become infected with HIV than were addicts who didn’t obtain needles from these programs.
Canadian studies have been misunderstood
Strathdee, who was an investigator in the Montreal study, says the research has been widely quoted by critics of needle-exchange programs, although the researchers’ final conclusions, published last year, are less well known. Initially, people had hypothesized that IDUs visiting needle-exchange programs were making more contacts, which led to more exposure and more opportunity for HIV infection. But that wasn’t the case; the problem, she says, was selection bias.
Deciding that needle exchange programs cause higher HIV infection rates because many needle-exchange users become infected with HIV would be like concluding that hospitals cause people to die because hospitalized people have a higher rate of death than the general population, Strathdee explains.
A sophisticated analysis of the data showed that the higher rates of HIV infection among the needle-exchange participants were due to the fact that the people who attended the Canadian needle exchanges were injecting drugs more frequently and were more dependent on drugs than were the people who chose not to participate in needle exchanges.
"The control group [in Canada] isn’t really an adequate comparison because they’re lower-risk people, and those people were getting their needles from pharmacies because they tended to be higher socioeconomic-status individuals," Strathdee says.
"That’s especially the case in Canada, where there is legal access to syringes in pharmacies, whereas in most U.S. cities there is no such access," she adds. "And that really helps to explain why two Canadian studies have shown this huge difference, [and] where most U.S. studies have not."
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