title: Incident HIV infection in a high-risk, homosexual, male cohort in Rio de Janeiro, Brazil.
abstract: An HIV seroincidence study was conducted to identify a high-risk population for HIV prevention trials. Inclusion criteria were male gender, homosexual behavior, age between 18 and 50 years, and negative HIV serostatus; 862 study subjects were screened and 753 were enrolled and observed during follow-up for a mean of 1.5 years. In this population, 34 people had HIV seroconversions for an overall annual seroincidence of 3.1% (95% confidence interval [CI], 2.1%-4.1%). Among study subjects <20 years old, annual incidence was 8.4% (95% CI, 1.7%-15%). Independent risk factors for seroconversion were age <25 years (p = .01), hepatitis B core antibody seropositivity (p > .01), sex at first encounter in the preceding 6 months (p = .11), and a history of gonorrhea or condyloma in the 6 months before seroconversion (p = .04 and p = .08, respectively). At enrollment, 85% of the eventual seroconverters said they would participate in a vaccine trial; all agreed to participate when told there would be a placebo arm. Follow-up rates were 97%, 91%, and 88% at 6, 12, and 18 months, respectively. The HIV-1 subtype was B for each of the first 17 seroconverters. These data demonstrate the suitability of this cohort for HIV prevention trials, based on high HIV incidence and retention rates, and a willingness to participate in such trials.
authors.affiliation: Departments of Epidemiology and Medicine, University Pittsburgh Graduate School of Public Health, Pennsylvania 15261, USA. lharriso@edc.grsph.pitt.edu
authors.forename: L H
authors.initials: LH
authors.lastname: Harrison
authors.forename: R F
authors.initials: RF
authors.lastname: do Lago
authors.forename: R K
authors.initials: RK
authors.lastname: Friedman
authors.forename: J
authors.initials: J
authors.lastname: Rodrigues
authors.forename: E M
authors.initials: EM
authors.lastname: Santos
authors.forename: M F
authors.initials: MF
authors.lastname: de Melo
authors.forename: L H
authors.initials: LH
authors.lastname: Moulton
authors.forename: M
authors.initials: M
authors.lastname: Schechter
mesh_terms: D016915:AIDS Vaccines; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001938:Brazil / Q000453:epidemiology; D015331:Cohort Studies; D003218:Condylomata Acuminata / Q000453:epidemiology; D016001:Confidence Intervals; D004797:Enzyme-Linked Immunosorbent Assay; D006069:Gonorrhea / Q000453:epidemiology; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission; D018023:HIV Seronegativity; D006679:HIV Seropositivity / Q000453:epidemiology; D018451:Homosexuality, Male; D006801:Humans; D015994:Incidence; D008297:Male; D012307:Risk Factors; D012309:Risk-Taking; D014505:Urban Population / Q000706:statistics & numerical data
chemical_list: D016915:AIDS Vaccines