Miller Joel C, Slim Anja C
Institute for Disease Modeling, Bellevue, WA, United States of America.
School of Mathematical Sciences, Monash University, Clayton, VIC, Australia.
PLoS One. 2017 Nov 14;12(11):e0187938. doi: 10.1371/journal.pone.0187938. eCollection 2017.
Sexual partnerships that overlap in time (concurrent relationships) may play a significant role in the HIV epidemic, but the precise effect is unclear. We derive edge-based compartmental models of disease spread in idealized dynamic populations with and without concurrency to allow for an investigation of its effects. Our models assume that partnerships change in time and individuals enter and leave the at-risk population. Infected individuals transmit at a constant per-partnership rate to their susceptible partners. In our idealized populations we find regions of parameter space where the existence of concurrent partnerships leads to substantially faster growth and higher equilibrium levels, but also regions in which the existence of concurrent partnerships has very little impact on the growth or the equilibrium. Additionally we find mixed regimes in which concurrency significantly increases the early growth, but has little effect on the ultimate equilibrium level. Guided by model predictions, we discuss general conditions under which concurrent relationships would be expected to have large or small effects in real-world settings. Our observation that the impact of concurrency saturates suggests that concurrency-reducing interventions may be most effective in populations with low to moderate concurrency.
在时间上重叠的性伴侣关系（同时存在的关系）可能在艾滋病流行中发挥重要作用，但确切影响尚不清楚。我们推导了在理想化动态人群中，存在和不存在同时性关系时疾病传播的基于边的分区模型，以便研究其影响。我们的模型假设伴侣关系随时间变化，个体进入和离开高危人群。受感染个体以恒定的每个伴侣关系的速率将病毒传播给其易感伴侣。在我们理想化的人群中，我们发现参数空间的区域，其中同时性伴侣关系的存在导致增长大幅加快和更高的平衡水平，但也存在同时性伴侣关系的存在对增长或平衡影响很小的区域。此外，我们发现了混合模式，其中同时性关系显著增加早期增长，但对最终平衡水平影响很小。根据模型预测，我们讨论了在现实世界环境中，预计同时性关系会产生大或小影响的一般条件。我们观察到同时性的影响会饱和，这表明减少同时性的干预措施可能在低至中等同时性的人群中最有效。
