Objective: To assess recent developments in the HIV epidemic in injecting drug users (IDUs) in New York City. With >50,000 cases of AIDS in IDUs, New York has experienced the largest HIV/AIDS epidemic in IDUs of any city in the world.
Methods: Serial cross-sectional surveys conducted continuously from 1990 to 2001 of IDUs entering the Beth Israel Medical Center (BIMC) drug detoxification program in New York City. HIV serostatus, use of prevention services, and risk behaviors were measured. Individuals were permitted to participate multiple times in the surveys but not more than once in any year.
Results: Two thousand eight hundred eighty-seven individuals contributed 3100 observations from 1990 to 2001. There was a substantial and consistent decline in the prevalence of HIV infection among IDUs entering the BIMC detoxification program, from 54% (165/304) in 1991 to 13% (39/303) in 2001 (P < 0.0001). The decline was highly linear, with r2 = 0.92 and a slope of -3.7% in seroprevalence per year. The decline occurred for both males and females, both short and long-term IDUs, and the three largest racial/ethnic subgroups (all P < 0.001 by Cochran-Armitage testing). Use of HIV prevention services increased substantially, particularly syringe exchange and voluntary HIV counseling and testing. General reductions in injection risk behaviors occurred, but substantial numbers of IDUs continued to engage in both receptive and distributive syringe sharing. Two conditional types of risk reduction not currently recommended by health authorities were reported: "informed altruism," in which persons who knew that they were HIV seropositive reduced transmission behavior, and "partner restriction," in which persons who shared needles and syringes primarily confined this sharing within small social networks.
Conclusions: HIV infection continues to decline in this population of IDUs in New York City, suggesting the possibility of bringing very high prevalence epidemics under control. Risk elimination may not be required; rather, multiple forms of risk reduction may be effective in reducing HIV transmission within a local population of IDUs.