Effectiveness of an evidence-based HIV prevention intervention when implemented by frontline providers.

Carefully conducted randomized trials have established that sexual behavior change interventions can significantly reduce intervention participants' risk of acquiring HIV. Establishing the effectiveness of these evidence-based interventions when implemented by frontline HIV prevention service providers is increasingly important in order to achieve maximum public health impact. This study sought to assess the effectiveness of an evidence-based intervention when implemented by frontline HIV prevention service providers. We evaluated Sisters Informing Sisters on Topics about AIDS (SISTA), an HIV prevention intervention for heterosexual African American women, as implemented by four AIDS service organizations. Women enrolled in HIV counseling, testing, and referral (CTR) at each agency served as contemporaneous controls. Measures included self-reported number of occasions of unprotected vaginal intercourse and number of vaginal sex partners in the previous 90 days. 1,262 participants completed baseline and follow-up assessments across both conditions (SISTA = 537 [57%]; CTR = 725 [62%]). In the full sample of HIV-negative women, CTR participants' odds of having had unprotected sex decreased over time by 38% while SISTA participants' odds of having had unprotected sex did not change. Similar results were found among only those participants who had sex at baseline. Hypothesized interaction effects indicating positive changes in sexual risks over time for SISTA participants were not observed.