Department of Medicine, University of California San Diego, San Diego, CA, USA.
Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK.
Lancet HIV. 2018 Jun;5(6):e309-e316. doi: 10.1016/S2352-3018(18)30062-6.
Patients who do not disclose their sexuality, including men who do not disclose same-sex behaviour, are difficult to characterise through traditional epidemiological approaches such as interviews. Using a recently developed method to detect large networks of viral sequences from time-resolved trees, we localised non-disclosed men who have sex with men (MSM) in UK transmission networks, gaining crucial insight into the behaviour of this group.
For this phylogenetic analysis, we obtained HIV pol sequences from the UK HIV Drug Resistance Database (UKRDB), a central repository for resistance tests done as part of routine clinical care throughout the UK. Sequence data are linked to demographic and clinical data held by the UK Collaborative HIV Cohort study and the national HIV/AIDS reporting system database. Initially, we reconstructed maximum likelihood phylogenies from these sequences, then sequences were selected for time-resolved analysis in BEAST if they were clustered with at least one other sequence at a genetic distance of 4·5% or less with support of at least 90%. We used time-resolved phylogenies to create networks by linking together nodes if sequences shared a common ancestor within the previous 5 years. We identified potential non-disclosed MSM (pnMSM), defined as self-reported heterosexual men who clustered only with men. We measured the network position of pnMSM, including betweenness (a measure of connectedness and importance) and assortativity (the propensity for nodes sharing attributes to link).
14 405 individuals were in the network, including 8452 MSM, 1743 heterosexual women and 1341 heterosexual men. 249 pnMSM were identified (18·6% of all clustered heterosexual men) in the network. pnMSM were more likely to be black African (p<0·0001), less likely to be infected with subtype B (p=0·006), and were slightly older (p=0·002) than the MSM they clustered with. Mean betweenness centrality was lower for pnMSM than for MSM (1·31, 95% CI 0·48-2·15 in pnMSM vs 2·24, 0·98-3·51 in MSM; p=0·002), indicating that pnMSM were in peripheral positions in MSM clusters. Assortativity by risk group was higher than expected (0·037 vs -0·037, p=0·01) signifying that pnMSM were linked to each other. We found that self-reported heterosexual men were more likely to link MSM and heterosexual women than heterosexual women were to link MSM and heterosexual men (Fisher's exact test p=0·0004; OR 2·24) but the number of such transmission chains was small (only 54 in total vs 32 in women).
pnMSM are a subgroup distinct from both MSM and from heterosexual men. They are more likely to choose sexual partners who are also pnMSM and might exhibit lower-risk sexual behaviour than MSM (eg, choosing low-risk partners or consistently using condoms). Heterosexual men are the group most likely to be diagnosed with late-stage disease (ie, low CD4 counts) and non-disclosed MSM might put female partners at higher risk than heterosexual men because non-disclosed MSM have male partners. Hence, pnMSM require specific consideration to ensure they are included in public health interventions.
National Institutes of Health.
包括不披露同性性行为的男性在内的不披露性取向的患者，很难通过传统的流行病学方法（如访谈）进行描述。我们使用最近开发的一种方法，从时间分辨树中检测病毒序列的大型网络，对英国传播网络中的男男性行为者（MSM）进行了定位，深入了解了这一群体的行为。
在这项系统发育分析中，我们从英国艾滋病毒耐药性数据库（UKRDB）中获得了 HIV pol 序列，该数据库是英国各地常规临床护理中进行耐药性检测的中央存储库。序列数据与 UKRDB 中 UK 协作艾滋病毒队列研究和国家艾滋病毒/艾滋病报告系统数据库中的人口统计学和临床数据相关联。最初，我们从这些序列中重建最大似然系统发育树，然后如果序列在遗传距离为 4.5%或更小且支持率至少为 90%的情况下与至少一个其他序列聚类在一起，则选择序列进行 BEAST 时间分辨分析。我们使用时间分辨系统发育树通过将共享 5 年内共同祖先的节点链接在一起来创建网络。我们确定了潜在的非披露 MSM（pnMSM），定义为自我报告的异性恋男性，他们只与男性聚类。我们测量了 pnMSM 的网络位置，包括中间中心性（连接性和重要性的度量）和配价（节点共享属性的倾向）。
网络中共包括 14405 人，包括 8452 名 MSM、1743 名异性恋女性和 1341 名异性恋男性。在网络中发现了 249 名 pnMSM（所有聚类的异性恋男性的 18.6%）。与他们聚类的 MSM 相比，pnMSM 更可能是黑人非洲裔（p<0.0001），不太可能感染 B 亚型（p=0.006），并且年龄稍大（p=0.002）。与 MSM 相比，pnMSM 的平均中间中心性较低（1.31，95%CI 0.48-2.15 在 pnMSM 中与 2.24，0.98-3.51 在 MSM 中；p=0.002），表明 pnMSM 在 MSM 聚类中处于边缘位置。按风险组计算的配价高于预期（0.037 与-0.037，p=0.01），表明 pnMSM 相互关联。我们发现，自我报告的异性恋男性比异性恋女性更有可能将 MSM 和异性恋女性联系起来，而异性恋女性则更不可能将 MSM 和异性恋男性联系起来（Fisher 精确检验 p=0.0004；OR 2.24），但这种传播链的数量很少（总共只有 54 个，而女性有 32 个）。
pnMSM 是一个与 MSM 和异性恋男性都不同的亚组。他们更有可能选择也是 pnMSM 的性伴侣，并且可能比 MSM 表现出较低的风险性行为（例如，选择低风险的伴侣或始终使用避孕套）。异性恋男性是最有可能被诊断为晚期疾病（即低 CD4 计数）的群体，并且可能比异性恋男性将女性伴侣置于更高的风险之中，因为 pnMSM 有男性伴侣。因此，pnMSM 需要特别考虑，以确保他们被纳入公共卫生干预措施。
美国国立卫生研究院。
