Recent HIV Infection among men who have sex with men and transgender women in Tijuana

ABSTRACT OBJECTIVE To characterize recent HIV infections among newly diagnosed men who have sex with men and transgender women in Tijuana. METHODS Limiting Antigen (LAg)-Avidity testing was performed to detect recent HIV infection within a cohort of newly-diagnosed men who have sex with men and transgender women in Tijuana. Logistic regression was used to determine characteristics associated with recent infection. A partial transmission network was inferred using HIV-1 pol sequences. Tamura-Nei 93 genetic distances were measured between all pairs of sequences, and the network was constructed by inferring putative transmission links (genetic distances ≤ 1.5%). We assessed whether recent infection was associated with clustering within the inferred network. RESULTS Recent infection was detected in 11% (22/194) of newly-diagnosed participants. Out of the participants with sequence data, 60% (9/15) with recent infection clustered compared with 31% (43/139) with chronic infection. Two recent infections belonged to the same cluster. In adjusted analyses, recent infection was associated with years of residence in Tijuana (OR = 1.5; 95%CI 1.01–1.09), cocaine use (past month) (OR = 8.50; 95%CI 1.99–28.17), and ever experiencing sexual abuse (OR = 2.85; 95%CI 1.03–7.85). DISCUSSION A total of 11% of men newly diagnosed with HIV who have sex with men and transgender women in Tijuana were recently infected. The general lack of clustering between participants with recent infection suggests continued onward HIV transmission rather than an outbreak within a particular cluster.

摘要
研究目的：对墨西哥蒂华纳地区新确诊的男男性行为者及跨性别女性的近期HIV感染特征展开分析。
研究方法：本研究针对蒂华纳地区新确诊的男男性行为者及跨性别女性队列，采用限制性抗原（Limiting Antigen, LAg）亲和力检测以识别近期HIV感染者；通过logistic回归分析与近期感染相关的特征；利用HIV-1 pol基因序列推断部分传播网络。对所有序列对计算Tamura-Nei 93遗传距离，以遗传距离≤1.5%作为阈值推断潜在传播关联并构建传播网络；同时评估近期感染与推断网络中的病毒聚类是否存在关联。
研究结果：本研究共纳入194名新确诊参与者，其中11%（22/194）被检出为近期HIV感染者。在携带基因序列数据的参与者中，近期感染者的病毒聚类比例为60%（9/15），慢性感染者为31%（43/139）；其中2例近期感染者属于同一病毒聚类。校正混杂因素后的分析显示，近期感染与在蒂华纳的居住年限（优势比（odds ratio, OR）=1.5，95%置信区间（confidence interval, 95%CI）=1.01~1.09）、近1个月内可卡因使用史（OR=8.50，95%CI=1.99~28.17）以及曾遭受性虐待（OR=2.85，95%CI=1.03~7.85）显著相关。
讨论：蒂华纳地区新确诊的男男性行为者及跨性别女性中，共有11%为近期HIV感染者。近期感染者整体病毒聚类比例较低，提示HIV仍在持续发生人际传播，而非局限于某一特定聚类的暴发流行。