South African Centre for Epidemiological Modelling and Analysis, University of Stellenbosch, South Africa.
World Health Organization, Geneva, Switzerland.
Epidemics. 2018 Jun;23:11-18. doi: 10.1016/j.epidem.2017.10.002. Epub 2017 Oct 26.
Random mixing in host populations has been a convenient simplifying assumption in the study of epidemics, but neglects important differences in contact rates within and between population groups. For HIV/AIDS, the assumption of random mixing is inappropriate for epidemics that are concentrated in groups of people at high risk, including female sex workers (FSW) and their male clients (MCF), injecting drug users (IDU) and men who have sex with men (MSM). To find out who transmits infection to whom and how that affects the spread and containment of infection remains a major empirical challenge in the epidemiology of HIV/AIDS. Here we develop a technique, based on the routine sampling of infection in linked population groups (a social network of population types), which shows how an HIV/AIDS epidemic in Can Tho Province of Vietnam began in FSW, was propagated mainly by IDU, and ultimately generated most cases among the female partners of MCF (FPM). Calculation of the case reproduction numbers within and between groups, and for the whole network, provides insights into control that cannot be deduced simply from observations on the prevalence of infection. Specifically, the per capita rate of HIV transmission was highest from FSW to MCF, and most HIV infections occurred in FPM, but the number of infections in the whole network is best reduced by interrupting transmission to and from IDU. This analysis can be used to guide HIV/AIDS interventions using needle and syringe exchange, condom distribution and antiretroviral therapy. The method requires only routine data and could be applied to infections in other populations.
在传染病研究中，宿主群体的随机混合一直是一个方便的简化假设，但忽略了群体内部和群体之间接触率的重要差异。对于艾滋病毒/艾滋病，在流行集中于高危人群的情况下，如性工作者（FSW）及其男性顾客（MCF）、注射吸毒者（IDU）和男男性接触者（MSM），随机混合的假设是不恰当的。了解谁将感染传播给了谁，以及这如何影响感染的传播和控制，仍然是艾滋病毒/艾滋病流行病学中的一个主要经验挑战。在这里，我们开发了一种技术，基于在相关人群群体（人群类型的社交网络）中对感染的常规抽样，该技术显示了越南芹苴省的艾滋病毒/艾滋病疫情如何从性工作者开始，主要通过注射吸毒者传播，并最终导致 MCF 的女性伴侣（FPM）中出现大多数病例。计算群体内部和群体之间以及整个网络的病例繁殖数，为不能简单地从感染流行率的观察中推断出的控制提供了见解。具体来说，从性工作者到 MCF 的艾滋病毒传播人均率最高，大多数艾滋病毒感染发生在 FPM 中，但通过中断 IDU 的传播，可以最好地减少整个网络中的感染数量。这种分析可以用于指导使用针具交换、避孕套分发和抗逆转录病毒疗法的艾滋病毒/艾滋病干预措施。该方法仅需要常规数据，并且可以应用于其他人群的感染。
