Needle exchange programs aim to reduce the risk of illness spread through shared needles, whose use raises the risk for spreading and contracting infections such as HIV and hepatitis B and C. But a number of drug users interviewed in the two-year study still persisted in sharing needles with close friends, the researchers wrote in the March issue of the American Journal of Public Health.

“Although needle exchange programs have provided a needed service in permitting access to sterile syringes for injection drug users who cannot or will not stop injecting, these data suggest that programs need to renew efforts to discourage further sharing of syringes obtained from the program,” wrote Thomas W. Valente, associate professor of preventive medicine, and colleague David Vlahov, director of the Center for Urban Epidemiologic Studies at the New York Academy of Medicine. The researchers conducted the study when both were with the School of Hygiene and Public Health at Johns Hopkins University.

Valente is an associate professor in the Keck School of Medicine of USC’s Institute for Prevention Research.

Valente and Vlahov examined risky behavior among 1,184 injection drug users who visited a needle exchange program in Baltimore, Md., between 1995 and 1997. They asked participants about their drug use and gathered information about the participants’ network of friends and their recent habits: whether they injected drugs, shared syringes, had sex or drank alcohol together.

Researchers noted that the program succeeded in reducing needle sharing overall. Of the study subjects, only 203 (about 17 percent) reported they had recently shared a syringe. In other studies of the same population, needle sharing declined from 70 percent of users in 1990 to less than 25 percent of users in 2000.

Users did not take risks randomly. Of the 203 users who said they had recently shared a syringe, 159 (or 78 percent) reported sharing it with a friend.

When drug users confine their drug use to a circle of close friends, in a population with low prevalence of disease, they minimize the risk of contracting disease to an extent, the researchers noted. But users changed friends often during the study, increasing the risk of disease. Prevalence of disease, such as hepatitis C, among needle exchange program users also was high – increasing the risk of infection.

Injection drug use is a serious problem in the United States, according to the Centers for Disease Control and Prevention. Through 1996, one-third of all reported AIDS cases nationwide could be traced to injection drug use.

“Needle exchange may reduce the degree of syringe sharing that occurs because of legal restrictions and costs, but so far it hasn’t eliminated risk due to syringe sharing for social or ritualistic reasons,” Valente said. “Injection drug users still feel compelled to share syringes with their close friends. They consume alcohol and drugs with their friends, and refusal to share a syringe in such settings would indicate a lack of trust among friends.”

Vlahov said the study indicates disease prevention efforts need to improve education to get people not to share needles at all.

“Clearly, stopping drug use is a goal, but for those who won’t or who can’t stop drug use, using a clean needle each time they inject and not sharing with others is key to HIV prevention,” Vlahov said. “People working in HIV prevention need to get the message out that sharing [needles] with friends might seem natural and safe, but that isn’t necessarily so.

“It is safer to use your own needle, and even safer to stop injecting altogether.”