Background:  Chemoprophylaxis is a promising approach to HIV prevention. The iPrEx trial started screening in June 2007 in the Andean region. Assessing risk at screening would allow us to test the hypothesis that PrEP will attract extremely high risk persons who would not otherwise avail themselves of prevention services.

Methods:  A computer-assisted self-administered interview is completed by all men who have signed consent for trial screening. Data were also available from the trial database on HIV test results and eligibility outcomes of the screening.

Results:  Computer-assisted self-administered interview data were available on 416 men who met the risk screening criteria to date. Risk factors for HIV were older age of sexual debut (x = 15.0), history of drug use (32%), past treatment for a sexually transmitted infection (32.5%), previous HIV test (75.9%), having paid (19.9%) or having been paid for sex (59%), having unprotected receptive or insertive anal intercourse with someone believed to be positive (18.6%), or even having >150 lifetime male partners (22.6%). While 8.4% of men who screened tested positive for HIV, reports of recent sexual activity indicated HIV^– men were at higher risk for infection with an average of 15.2 or median of 6 partners in the past 3 months compared to 9.6 and 3 for HIV⁺ men. The results for unprotected receptive or insertive anal intercourse were similar; HIV^– men averaged 16.9 or a median 7.0 episodes of unprotected anal intercourse in the last 3 months compared to 15.3 and 10 for HIV⁺ men. None of these differences reached statistical significance. The 2 main differences between the groups is that while 3 (8.6%) of HIV⁺ reported only being the insertive partner 23.6% of HIV^– did so, the percentages of those only being the receptive partner were not different. Yet 51.4% of HIV⁺ reported being sexually “versatile” compared to 34.4% of HIV^–. The HIV⁺ testers were older than HIV^– by 2.6 years and this difference was significant (p = 0.033).

Conclusions:  The implementation of iPrEx has indicated acceptability of the concept of PrEP in the HIV-affected community and among the target population. The relatively high rate of previous HIV testing reported and analysis of attitudes and knowledge indicate that these men are not naïve about the risks of HIV in spite of ongoing behavior, and are eager to participate in a PrEP-based intervention.