Epidemiologic Study on Changing HIV Risks Among FSW-IDUs on the Mexico-US Border

在全球范围内，注射毒品的暗娼是重要的“桥梁”人群，可将艾滋病毒/性传播感染传播给一般人群；然而，缺乏减少其注射和性风险的干预措施。这项流行病学研究的总体目标是在墨西哥和美国的两个边境城市同时减少FSW-IDU的高危性行为和注射行为，其中艾滋病毒流行率最近从 2%到14%；46%的人至少有一次活跃的性传播感染。我们的具体目标是：目的1)评估行为干预的效果，以减少注射吸毒者共用注射器和注射用具。我们假设，在积极的实验性注射风险教育条件下，FSW-IDU将报告：(A)共用针头的接受性和分布性较差；(B)共用注射用具较少；(C)从更安全的来源获得注射器和注射用具。目的2)评估在持续吸毒的背景下增加FSW-IDU安全套使用的行为干预的有效性。我们假设，处于积极试验性风险降低状态的FSW-IDU将：(A)报告较少的无保护措施的阴道和肛交；(B)较少发生特定性传播感染的病例。目的3)评价这两种行为干预措施在暗娼中增加避孕套使用率和减少共用针头/注射用具的联合效果。我们假设，这些干预措施的联合作用将产生更大的风险降低。 与单独进行干预相比。目的4)确定我们干预措施中理论上重要的组成部分(即自我效能、结果预期、态度、意图)在多大程度上代表了基本结果变化的潜在机制(例如性和注射相关的风险降低)。目的5)探讨a)性风险降低干预和b)性风险降低干预效果的亚组差异。 基于背景特征、情境因素、社会因素和个人因素的注射降低风险干预。为了实现这些目标，我们将招募600名艾滋病毒阴性的FSW-IDU(在提华纳每人300名 和CD。华雷斯)，并将妇女随机分成三个时间相同的组(组1：注射风险干预和教导性安全性行为教育；组2：性风险干预和教导性安全注射 教育；第3组：积极注射和性干预)。在每个城市，将使用集群随机化来最大限度地减少污染。所有妇女都接受免费的性传播感染治疗，并将在4个月、8个月和12个月进行随访。我们的设计使我们能够“拆开”干预措施，以确定其成分在减少注射和/或性风险方面是否同样有效，或者是否需要更密集的条件来改变 艾滋病毒/性传播感染的流行病学，因此对墨西哥和美国有直接的、切实的政策影响。降低FSW-IDU中艾滋病毒风险的干预措施可能会遏制美国-墨西哥边境地区迅速蔓延的艾滋病毒流行，并适用于其他资源匮乏的国家。

Globally, FSWs who inject drugs (FSW-IDUs) are important `bridge' populations that can transmit HIV/STIs to the general population; however, interventions to reduce both their injection and sexual risks are lacking. The overall goal of this epidemiologic study is to simultaneously reduce high risk sexual and injection behaviors among FSW-IDUs in two Mexico-U.S. border cities, among whom HIV prevalence has recently increased from 2% to 14%; 46% had at least one active STI. Our specific aims are: Aim 1) To evaluate the efficacy of a behavioral intervention to decrease sharing of syringes and injection paraphernalia among FSW-IDUs. We hypothesize that FSW-IDUs in the active experimental injection risk eduction ondition will report: (a) less receptive and distributive needle sharing; (b) less sharing of injection paraphernalia; (c) obtaining syringes and injection paraphernalia from safer sources. Aim 2) To valuate efficacy of a behavioral intervention to increase condom use among FSW-IDUs in the context of ongoing drug use. We hypothesize that FSW-IDUs in the active experimental sexual risk reduction condition will: (a) report less unprotected vaginal and anal sex; (b) have fewer incident cases of specific STIs. Aim 3) To evaluate the joint effects of these two behavioral interventions o increase condom use and reduce sharing of needles/injection paraphernalia among FSW- IDUs. We hypothesize that the joint effect of these interventions will generate greater risk reductions compared to either intervention alone. Aim 4) To determine the extent to which theoretically-important components of our interventions (i.e., self-efficacy, outcome expectancies, attitudes, intentions) represent underlying mechanisms of change in primary outcomes (i.e., sexual and injection-related risk reductions). Aim 5) To explore subgroup differences in the efficacy of a) the sexual risk reduction intervention and b) the injection risk reduction intervention based on background characteristics, contextual factors, social factors and intrapersonal factors. To meet these aims, we will recruit 600 HIV-negative FSW-IDUs (300 each in Tijuana and Cd. Juarez) and randomize women to one of three time-equivalent groups (Group 1: injection risk intervention and didactic safer sex education; Group 2: sexual risk intervention and didactic safer injection education; Group 3: Both active injection and sexual interventions). In each city, cluster randomization will be used to minimize contamination. All women receive free STI treatment and will be followed-up at 4, 8 and 12 months. Our design allows us to ‘ unpack' the intervention to determine whether its components are just as effective in reducing injection and/or sexual risks, or if the more intensive conditions are needed to alter the epidemiology of HIV/STIs, thus having direct, tangible policy implications for Mexico and the US. Interventions that reduce HIV risks among FSW-IDUs may curtail the burgeoning HIV epidemic in the U.S-Mexico border region, and have applicability to other resource-poor countries.