Feasibility of following an open cohort of homosexual and bisexual HIV negative men in Brazil, project Horizonte (1994-2010)
M. Carneiro1, M. Greco2, A.P. Silva2, J. Andrade2, E.I. Oliveira2, M.J. Utsch2, F.A. Ribeiro2, D.B. Greco2
1Federal University of Minas Gerais, Parasitology/Epidemiology, Belo Horizonte, Brazil, 2Federal University of Minas Gerais, Faculdade de Medicina - Project Horizonte, Belo Horizonte, Brazil
Background: Project Horizonte is an open cohort of homosexual/bisexual HIV negative men established in Belo Horizonte, Brazil. Its objectives are to evaluate HIV infection incidence, risk factors for infection, preventive tools, the possibility of conducting clinical trials of preventive HIV vaccines, and to discuss ethical and technical aspects of such trials. Here we discuss the feasibility of maintaining such a cohort for long periods of time.
Methods: The study protocol has two phases: the selection process and follow-up. During selection HIV-1 negative homosexual or bisexual male are identified and invited to participate in a cohort study. Volunteers are scheduled for biannual visits that include an interview using a psychosocial/epidemiological questionnaire, blood collection for HIV and other laboratory tests, and clinical consultation. Preventive interventions at each visit include free condom distribution, HIV/Aids information, and participation in discussion fora addressing questions such as sexuality, HIV vaccine trials, and safe sexual practices.
Results: From 1994 to 2010, 1187 volunteers were screened: 102 (8.6%) were ineligible (positive for HIV); 1085 were enrolled; 565 were lost of follow-up with 72% of the losses occurring before the fourth visit. Currently, 439 volunteers are followed; mean age is 27 years, 62% are mullatos, 55% receive less than 3 minimum wages, 47% finished high school. The overall incidence rate was 2.2/100 persons years; 70% of seroconvertions occurred up to the third visit. The majority (80%) said they would or might participate in vaccine trial and the main reason is altruism.
Conclusion: Project Horizonte is the longest running cohort of homosexual/bisexual men HIV negative in Brazil. The results attest the feasibility of following a cohort for extended period of time, of estimating HIV infection incidence and of evaluating counseling for safer sexual practices. The volunteers will certainly be capable of autonomously deciding to participate in future HIV vaccine trials.
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