Men who have sex with men (MSM) from Buenos Aires, Argentina: a suitable group for HIV clinical trials.

PANDO MA; WEISSENBACHER M; MARONE R; MONTANO S; CARBALLO DIEGUEZ A; SALOMON H; AVILA MM

Bangkok

Conferencia; AIDS Vaccine 2011; 2011

Global HIV Vaccine Enterprise

Background: For the past ten years (2000-2010), Argentina’s researchers have conducted HIV-related studies among men who have sex with men (MSM) in collaboration with an MSM NGO (Nexo Asociación Civil). The aim of this study is to establish feasibility and suitability of conducting HIV clinical trials on MSM in Buenos Aires, Argentina. Methods: Several cross-sectional studies and one follow-up cohort study were analyzed to determine HIV prevalence, incidence, and subtyping; risk factors; circumcision; behavioral factors; and willingness to participate in vaccine trials among MSM. Results: The estimated HIV prevalence has been 11-14% during the past ten years (800-1000 volunteers/year). HIV incidence, both in the cohort study and in cross sectional studies (Detune) was 4-6% persons-year. Phylogenetic analysis revealed that subtype B was the most common subtype present in MSM; yet, a higher frequency of non-B-subtypes (BF recombinants) was found in the last study conducted by the team as compared to previous studies (30.4% vs.10.5%, p<0.001). The one-year follow-up cohort study showed a retention rate of 91%. Studies also showed that about 50% of MSM have unprotected intercourse, 12.5% are circumcised, and 53% of men who attended the NGO for testing are repeated testers. More than 60% of MSM expressed willingness to participate in vaccine trials. Conclusions: The MSM population in Buenos Aires is very well characterized regarding HIV prevalence, incidence, molecular epidemiology, sexual risk behavior, and related parameters. Excellent retention rates were achieved in the past.  Participants indicated strong commitment to participate in HIV-related studies, including vaccine clinical trials. These data clearly indicate that MSM from Argentina constitute a suitable group for HIV vaccine clinical trials.