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The transnational cohort: global HIV epidemiology and prevention research for transwomen


It is a study with transgender women whose main objective is to estimate HIV incidence and to evaluate social determinants of health, including social and biomedical transition events of gender, risk behaviors related to the affirmation of gender and multiple forms of stress at all behavioral ecological levels of influence associated with HIV acquisition. The project foresees the establishment of cohorts in Brazil (São Paulo), USA (San Francisco), Namibia (Windhoek) and China (Nanjing). It is funded by the National Institute of Mental Health, National Institutes of Health (NIMH / NIH), and is structured in three main components: 1. A qualitative component (SF), SF, Nanjing and Windhoek, for questionnaires and evaluation of cognitive tests; 2. A cross-sectional study to estimate HIV prevalence and risk behaviors in SF, SP and Nanjing; and, 3. A prospective transnational cohort in São Francisco and São Paulo, which is the subject of this proposal - constitutes a cohort of HIV negative women to be followed to measure the incidence of HIV and its determinants. The specific conceptual framework for HIV risk assessment will be based on three models: 1. The Behavioral Ecological Model, 2. The Gender Affirmation Model, and 3. The Minority Stress Model (Minority Stress Model). The transnational cohort will allow us to assess the positive and negative impact of social and biomedical transition events on HIV incidence and preventive behaviors, and will test the hypothesis that biomedical transition events of gender can both result in periods of high HIV risk and are precursors of protective health behaviors. Focusing on these events will help identify the targets for new prevention interventionsMethodology: An open cohort study that includes transsexual and transvestite women, over 18 years of age, who are HIV negative, and who agree to participate in the study by signing the informed consent form. Participants are recruited through the Respondent Driven Sampling (RDS) sampling strategy, suitable for difficult access populations. The sample size was calculated to compose the cohort and produce 1,500 person-years of follow-up in 1100 transsexual and non-HIV-infected transvestites, with 550 for each city (SF and SP), considering a 10% loss of follow-up. The incidence of HIV among transsexual and transvestite women is estimated at 3.4 and 5.6 per 100 person-years in SF and SP, respectively. Thus, this sample size will be able to estimate HIV incidence ranging from 2.5 to 5.0 per 100 person-years, considering a precision of 5% and statistical power of 80%. Each participant will have visits every six months for a period of 18 months and the study lasts for five years. For statistical analysis, the follow-up time will be defined between the first interview and the date of the first positive HIV test among those who seroconverted or the date of the end of the study or last follow-up visit for those who remain HIV negative. At each visit, participants are interviewed and have collected blood samples for laboratory tests, including a serological diagnosis for the detection of HIV antibodies (screening and confirmatory). The data is collected through a computer and the Questionnaire Development System (QDS) is the system used for storage and processing. For the statistical analysis, appropriate methods will be used for the RDS methodology, including weighting for the recruitment dependency of pairs (hemophilia). The incidence of cumulative HIV and person-time will be estimated, with the denominator for the first being the number of participants at the beginning of the study and for the second the sum of the follow-up time. (AU)

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