In developing HIV prevention efforts, it is critical to determine whet
her interventions are effective in achieving declines in risk behavior
among both HIV-positive and HIV-negative individuals. Based on a mult
isite intervention study of injection drug users (IDUs) and crack smok
ers, 488 seropositive IDUs and 364 seropositive crack users were compa
red with randomly selected matched samples of seronegatives (with matc
hing based on recruitment site, gender, age group and ethnicity) at ba
seline and six-month follow-up to compare changes in risk behaviors by
serostatus. Results indicated that overall. risk behaviors declined s
ubstantially over time; significant interaction effects indicated that
seropositives reported a greater decline in sex risk behaviors than s
eronegatives. These data support the utility of HIV testing for high-r
isk drug users, and indicate that interventions have produced reductio
ns in risk behaviors of both seropositives and seronegatives. Further
research on the impact of site seroprevalence, and to enhance our unde
rstanding of those who continue to engage in risky behaviors, is neede
d.