RISK BEHAVIOR AND HIV SEROINCIDENCE AMONG OUT-OF-TREATMENT INJECTION-DRUG USERS - A 4-YEAR PROSPECTIVE-STUDY

We monitored trends in HIV risk behaviors and seroconversion among out -of-treatment injection drug users (IDUs) receiving street-based outre ach intervention. Beginning in 1988, 641 HIV-seronegative IDUs were re cruited by targeted sampling methods to reflect broader IDU population s and were followed for 4 years (1988-1992). All were active injectors not in treatment when recruited. Cohort members were targets of HIV-p revention outreach. The intervention was guided by the Indigenous Lead er Outreach Model: Exaddicts deliver HIV-prevention services targeting IDU social networks in community settings. Primary outcome measures w ere HIV seroconversion and HIV risk behaviors. Observed incidence of H IV infection decreased, from 8.4 to 2.4 per 100 person-years. Prevalen ce of drug risk behaviors also decreased, from 100 to 14%. Seroconvers ion was associated with injection risk behavior [risk ratio (RR) = 9.8 ]. Sex risk behavior also decreased, but less dramatically, from 71 to 45%. Out-of-treatment IDUs in Chicago have reduced their rates of new HIV infection by reducing their injection risk behavior. New infectio ns were strongly associated with injection risk behavior but not with sex risk behavior.