Design, implementation, and evaluation at entry of a prospective cohort study of homosexual and bisexual HIV-1-negative men in Belo Horizonte, Brazil: Project Horizonte

Background and Objectives: Project Horizonte, an open cohort of homosexual and bisexual HIV-l-negative men, is a component of the Minas Gerais AIDS Va ccine Program of the Federal University of Minas Gerais, Belo Horizonte, Br azil. Its objectives included the evaluation of seroincidence of HIV, to as certain the role of counseling on behavior modification and to assess their willingness to participate in future HIV vaccine trials. Methods: Various means of recruitment were used, including pamphlets, notic es in community newspapers, radio, and television, at anonymous testing cen ters;, and by word of mouth. Results: From October 1994 to May 1999, 470 volunteers were enrolled, Their mean age was 26 years and over 70% of them had high school or college educ ation. During the follow-up, they were seen every 6 months, when they recei ved counseling and condoms, and when HIV testing was done. Eighteen serocon versions were observed, and the incidence rates estimates were 1.75 per 100 and 1.99 per 100 person years, for 36 and 48 months of follow-up, respecti vely. During the entire period, 139 volunteers were lost to follow-up. Amon g them, 59 (42.4%) never returned after the initial visit and 51 (36.7) cam e only once after their initial visit. No losses were observed for those ob served during follow-up for more than 3 years. At enrollment, 50% of partic ipants said they would participate in a vaccine trial, and 30% said they mi ght participate. Conclusions: The results obtained up to this moment confirm the feasibility of following this type of cohort for an extended period, estimating HIV in cidence rate, and evaluating counseling for safe sexual practices in prepar ation for clinical trials with candidate HIV vaccines in Brazil.