Department of Mathematical Engineering, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
PLoS Comput Biol. 2013;9(3):e1002974. doi: 10.1371/journal.pcbi.1002974. Epub 2013 Mar 21.
The dynamic nature of contact patterns creates diverse temporal structures. In particular, empirical studies have shown that contact patterns follow heterogeneous inter-event time intervals, meaning that periods of high activity are followed by long periods of inactivity. To investigate the impact of these heterogeneities in the spread of infection from a theoretical perspective, we propose a stochastic model to generate temporal networks where vertices make instantaneous contacts following heterogeneous inter-event intervals, and may leave and enter the system. We study how these properties affect the prevalence of an infection and estimate R(0), the number of secondary infections of an infectious individual in a completely susceptible population, by modeling simulated infections (SI and SIR) that co-evolve with the network structure. We find that heterogeneous contact patterns cause earlier and larger epidemics in the SIR model in comparison to homogeneous scenarios for a vast range of parameter values, while smaller epidemics may happen in some combinations of parameters. In the case of SI and heterogeneous patterns, the epidemics develop faster in the earlier stages followed by a slowdown in the asymptotic limit. For increasing vertex turnover rates, heterogeneous patterns generally cause higher prevalence in comparison to homogeneous scenarios with the same average inter-event interval. We find that [Formula: see text] is generally higher for heterogeneous patterns, except for sufficiently large infection duration and transmission probability.
接触模式的动态性质产生了多样化的时间结构。特别是,实证研究表明,接触模式遵循异质的事件间时间间隔,这意味着高活动期之后是长时间的不活动期。为了从理论角度研究这些异质性对感染传播的影响,我们提出了一个随机模型来生成时间网络,其中顶点按照异质的事件间间隔进行瞬时接触,并且可能离开和进入系统。我们研究了这些特性如何影响感染的流行程度,并通过模拟感染(SI 和 SIR)与网络结构共同演化来估计 R(0),即完全易感人群中一个感染个体的二次感染数量。我们发现,与同质情景相比,在广泛的参数值范围内,异质接触模式会导致 SIR 模型中的疫情更早和更大,而在某些参数组合中可能会发生较小的疫情。对于 SI 和异质模式,疫情在早期阶段发展更快,随后在渐近极限处放缓。随着顶点周转率的增加,异质模式通常会导致比具有相同平均事件间间隔的同质情景更高的流行率。我们发现,除了感染持续时间和传播概率足够大的情况外,[Formula: see text]对于异质模式通常更高。