A theoretical single-parameter model for urbanisation to study infectious disease spread and interventions
A theoretical single-parameter model for urbanisation to study infectious disease spread and interventions
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DOI：
10.1371/journal.pcbi.1006879
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发表时间：
2019-03-01
影响因子：
4.3
通讯作者：
de Blasio, Birgitte Freiesleben
中科院分区：
文献类型：
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作者：
Engebretsen, Solveig;Engo-Monsen, Kenth;de Blasio, Birgitte Freiesleben
世界正在不断城市化，导致了人口密集的城市地区和人口稀少的农村地区。我们提出了一种生成空间场的方法，该方法具有可控制的种群聚类水平。我们构建了一个合成国家，并使用该方法生成不同聚类水平的国家版本。结合传染病传播的元人口模型，这使我们能够在计算机上探索城市化如何影响传染病传播。在没有干预措施的基线情景中，潜在的人口聚集似乎对流行病的最终规模和时间影响不大。在非通勤旅行的国内限制下，最终规模随着人口聚集的增加而减小。聚类程度越高，出行限制对减小最终规模的作用越大。农村地区的降幅更大。国内旅行限制延迟了疫情，在聚集程度较低的情况下，延迟最大。我们实施了三种不同的疫苗接种策略：统一疫苗接种（在空间上），优先接种城市地区和优先接种农村地区。城市和统一疫苗接种策略在减少最终规模方面最有效，而农村疫苗接种策略明显较差。对一些欧洲国家的目测显示，许多国家已经具有高人口聚集性。在未来，它们可能会变得更加集群。因此，根据我们的模型，国内旅行限制在延缓流行病方面可能越来越不有效，而在减少最终规模方面将更加有效。此外，为了尽量减少最终规模，重要的是在分发疫苗时不要忽视城市地点。据我们所知，这是第一次系统地调查城市化对传染病传播的影响，特别是检查预防措施作为城市化功能的有效性。我们研究了城市化与传染病传播之间的相互作用。作为全球城市化进程的一部分，人们不断向城市地区迁移，城市的规模也在不断扩大。这就造成了高人口密度地区的集群和低人口密度地区的集群，这就是我们所说的人口集群。通过模拟传染病在一个合成国家的传播，我们改变了这种人口聚集，我们探讨了城市化对传染病传播的影响。我们的定性结果对传染病控制指南和政策具有直接意义。我们发现，与城市化程度较低的国家相比，在城市化程度最高的国家实施国内旅行限制对最终患病人数的影响更大。这种影响在农村地区最为明显。根据我们的模型，在城市化程度较低的国家，旅行限制比城市化程度较高的国家更有效地延缓了疫情的蔓延。我们调查疫苗接种策略，根据它们是城市还是农村来确定目标地点。我们发现，在城市地区接种疫苗是很重要的，如果大多数城市地区没有接种疫苗，最终患病人数将会多得多。
The world is continuously urbanising, resulting in clusters of densely populated urban areas and more sparsely populated rural areas. We propose a method for generating spatial fields with controllable levels of clustering of the population. We build a synthetic country, and use this method to generate versions of the country with different clustering levels. Combined with a metapopulation model for infectious disease spread, this allows us to in silico explore how urbanisation affects infectious disease spread. In a baseline scenario with no interventions, the underlying population clustering seems to have little effect on the final size and timing of the epidemic. Under within-country restrictions on non-commuting travel, the final size decreases with increased population clustering. The effect of travel restrictions on reducing the final size is larger with higher clustering. The reduction is larger in the more rural areas. Within-country travel restrictions delay the epidemic, and the delay is largest for lower clustering levels. We implemented three different vaccination strategiesuniform vaccination (in space), preferentially vaccinating urban locations and preferentially vaccinating rural locations. The urban and uniform vaccination strategies were most effective in reducing the final size, while the rural vaccination strategy was clearly inferior. Visual inspection of some European countries shows that many countries already have high population clustering. In the future, they will likely become even more clustered. Hence, according to our model, within-country travel restrictions are likely to be less and less effective in delaying epidemics, while they will be more effective in decreasing final sizes. In addition, to minimise final sizes, it is important not to neglect urban locations when distributing vaccines. To our knowledge, this is the first study to systematically investigate the effect of urbanisation on infectious disease spread and in particular, to examine effectiveness of prevention measures as a function of urbanisation.Author summary We study the interplay between urbanisation and infectious disease spread. As part of the worldwide urbanisation process, people are continuously moving to urban areas, and the cities are growing in size. This causes clusters of areas with high population density and clusters of areas with low population density, which is what we call population clustering. By simulating infectious disease spread in a synthetic country where we vary this population clustering, we explore the consequences of urbanisation on infectious disease spread. Our qualitative results have direct implications for infectious disease control guidelines and policies. We find that implementing internal travel restrictions have greater impact on the final number ill in the most urbanised countries than in the less urbanised countries. The effect is largest in the more rural parts of the country. According to our model, travel restrictions are more effective in delaying the epidemic in the less urbanised countries than in the more urbanised countries. We investigate vaccination strategies, where locations are targeted depending on how urban or rural they are. We find that it is important to vaccinate the urban locationsif the most urban locations are not covered by the vaccine, the final number ill will be a lot larger.