High HIV Incidence And Willingness To Use Rectal Microbicides Among Argentine MSM. Potential For Rectal Microbicide Studies.

CARBALLO DIEGUEZ A; BALAN I; MARONE R; PANDO MA; DOLEZAL C; LEU CS; BARREDA V; AVILA MM

Pittsburgh, Pennsylvania

Conferencia; Microbicides 2010.; 2010

Objective.  Studies conducted in Buenos Aires, Argentina, repeatedly show high HIV incidence per 100 person years among MSM.  Rates were 6.7 in the Vignoles et al. (2006) cross-sectional study that used STARHS, and 3.9 in the Segura et al. (2007) study of a prospective cohort followed up for 12 months (retention: 97.2% at 6 months and 91.5% at 12 months). With prevention efforts limited to condom promotion and no locally developed, proven effective, behavioral interventions, new strategies are urgently needed.  We assessed HIV prevalence and incidence and studied acceptability of microbicides among MSM in Buenos Aires.   Methods.  500 MSM were recruited through Respondent Driven Sampling.  They provided blood samples and underwent CASI interviewing on microbicide acceptability. HIV-positive plasma samples were tested using a detuned version of an HIV-1 enzyme immunoassay (Vironostika HIV-1 Microelisa System; bioMerieux Inc, North Carolina, USA) to sort out potential recent infections (less than 6 months) from chronic infections using the STARHS strategy.  Microbicide acceptability was measured with questions on willingness to use a gel microbicide for anal sex measured on 10-point Likert scales ranging from 1= completely unwilling to 10 = completely willing.     Results. Sample HIV prevalence was 15.7 % (CI: 11.8-20.2), being higher among gay identified men (30.6 %) than non-gay identified  MSM (12.9%, ÷2 p <.001).  When the 85 HIV-positive plasma samples were tested using a detuned version of the HIV-1 enzyme immunoassay, 23 cases were identified as possible recent infections, this yielding an HIV incidence of 11.4 per 100 persons/year.   Incidence was significantly higher among gay men (22.6) than non-gay identified MSM (8.3).  Concerning willingness to use a gel microbicide during anal sex, although the mean score was 6.0 (neither willing nor unwilling), gay identified men scored significantly higher (7.1, willing range) than non-gay identified men (5.6) .   Discussion.  Gay identified MSM in Buenos Aires have high HIV prevelance and incidence and are willing to use gel rectal microbicides. Furthermore, the research infrastructure (i.e., laboratory facilities, demonstrated participant recruitment and retention success, record of scholarly activity of the University of Buenos Aires/Nexo Asociacion Civil, and effective collaboration with international partners) suggests great potential for successful collaborations in Phase 2 and 3 micro trials.