A competing-risks model explains hierarchical spatial coupling of measles epidemics en route to national elimination
A competing-risks model explains hierarchical spatial coupling of measles epidemics en route to national elimination
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DOI：
10.1038/s41559-020-1186-6
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发表时间：
2020-04-27
影响因子：
16.8
通讯作者：
Grenfell, Bryan T.
中科院分区：
文献类型：
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作者：
Lau, Max S. Y.;Becker, Alexander D.;Grenfell, Bryan T.
除了其全球健康的重要性，麻疹是一个范例，为低维机制的理解，当地的非线性人口相互作用。时空动力学的一个中心问题是麻疹持续性中从大城市到小城镇的分层传播和当地小人口集群之间的集合人口传播的相对作用。量化这一平衡对于规划区域消除和全球消除麻疹至关重要。然而，目前的重力模型不允许一个正式的比较等级与集合种群的传播。我们通过竞争风险框架来解决这一差距，捕捉竞争性感染源的相对重要性。我们将该方法应用于从1944年到20世纪90年代疫苗引起的感染最低点的英格兰和威尔士麻疹独特的时空详细的城市发病率数据集。我们发现，尽管少数大城市（例如，伦敦和利物浦）具有区域影响力，但邻近城镇和城市的集合人口聚集在推动疫苗接种前时代的国家动态方面发挥了重要作用。随着20世纪70年代和80年代疫苗接种水平的提高，空间可预测传播的特征减弱了：越来越多的感染是从可能在区域集合人群之外的无法识别的随机来源引入的。由此产生的不稳定动态突出表明，在疫苗接种覆盖率高的时候，要查明不断变化的感染源和确定发病模式是一项挑战。更广泛地说，潜在的发病率和人口统计数据，伴随着这篇论文，也将提供一个重要的资源，探索非线性时空populationdynamics.Using历史麻疹流行病学数据从英格兰和威尔士的竞争风险框架，作者发现，在邻近城镇和城市的集合人口聚集在推动国家动态在接种疫苗前的时代发挥了重要作用。
Apart from its global health importance, measles is a paradigm for the low-dimensional mechanistic understanding of local nonlinear population interactions. A central question for spatio-temporal dynamics is the relative roles of hierarchical spread from large cities to small towns and metapopulation transmission among local small population clusters in measles persistence. Quantifying this balance is critical to planning the regional elimination and global eradication of measles. Yet, current gravity models do not allow a formal comparison of hierarchical versus metapopulation spread. We address this gap with a competing-risks framework, capturing the relative importance of competing sources of reintroductions of infection. We apply the method to the uniquely spatio-temporally detailed urban incidence dataset for measles in England and Wales, from 1944 to the infection's vaccine-induced nadir in the 1990s. We find that despite the regional influence of a few large cities (for example, London and Liverpool), metapopulation aggregation in neighbouring towns and cities played an important role in driving national dynamics in the prevaccination era. As vaccination levels increased in the 1970s and 1980s, the signature of spatially predictable spread diminished: increasingly, infection was introduced from unidentifiable random sources possibly outside regional metapopulations. The resulting erratic dynamics highlight the challenges of identifying shifting sources of infection and characterizing patterns of incidence in times of high vaccination coverage. More broadly, the underlying incidence and demographic data, accompanying this paper, will also provide an important resource for exploring nonlinear spatiotemporal population dynamics.Using historic measles epidemiological data from England and Wales in a competing-risks framework, the authors find that metapopulation aggregation in neighbouring towns and cities played an important role in driving national dynamics in the prevaccination era.