Early dynamics of transmission and control of COVID-19: a mathematical modelling study
Early dynamics of transmission and control of COVID-19: a mathematical modelling study
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DOI：
10.1016/s1473-3099(20)30144-4
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发表时间：
2020-05-01
影响因子：
56.3
通讯作者：
Eggo, Rosalind M.
中科院分区：
文献类型：
--
作者：
Kucharski, Adam J.;Russell, Timothy W.;Eggo, Rosalind M.
背景截至2020年3月5日，严重急性呼吸综合征冠状病毒2型（SARS-CoV-2）的爆发已导致95333例确诊病例。了解感染的早期传播动态和评估控制措施的有效性对于评估在新地区发生持续传播的可能性至关重要。结合严重SARS-CoV-2传播的数学模型和武汉内外的四个数据集，我们估计了2019年12月至2020年2月武汉的传播情况。我们使用这些估计来评估如果出现病例，武汉以外地区发生持续人际传播的可能性。方法我们将随机传播模型与武汉2019年冠状病毒病（COVID-19）病例和国际病例的数据相结合。起源于武汉的病例来估计2020年1月和2020年2月期间传播如何随着时间的推移而变化。根据这些估计，我们计算了新引入病例可能在其他地区引发疫情的概率。为了估计武汉的早期传播动态，我们将随机传播动态模型拟合到武汉病例和武汉国际输出病例的多个公开数据集。我们拟合的四个数据集是：每日新增国际输出病例数（或无），截至2020年1月26日; 2019年12月1日至2020年1月1日，武汉每日新发病例数，截至发病日期，无市场暴露; 2019年12月29日至2020年1月23日期间，中国每日新发病例数，按发病日期划分;以及2020年1月29日至2020年2月4日期间，疏散航班上的感染乘客比例。我们使用了另外两个数据集与模型输出进行比较：（或缺乏）与武汉高度连通的国家（即前20个风险最高的国家），截至2020年2月10日;以及2020年1月16日至2月11日期间武汉报告的新增确诊病例数据，2020.研究结果我们估计武汉市的平均日繁殖数（R-t）从2.35下降到2.35，（95%CI 1.15-4.77）2020年1月23日实施旅行限制前1周，至1周后1.05（0.41-2.39）。根据我们对R-t的估计，假设SARS样变异，我们计算出，在1月初与武汉传播潜力相似的地区，一旦出现至少4例独立传入病例，该人群中建立感染的可能性超过50%。解释我们的结果显示，2020年1月下旬，武汉的COVID-19传播可能有所下降，与旅行控制措施的实施相吻合。随着越来越多的病例在这些控制措施之前到达与武汉类似传播潜力的国际地点，许多传播链可能最初无法建立，但最终可能导致新的疫情。版权所有（C）2020作者。爱思唯尔有限公司出版
Background An outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to 95 333 confirmed cases as of March 5, 2020. Understanding the early transmission dynamics of the infection and evaluating the effectiveness of control measures is crucial for assessing the potential for sustained transmission to occur in new areas. Combining a mathematical model of severe SARS-CoV-2 transmission with four datasets from within and outside Wuhan, we estimated how transmission in Wuhan varied between December, 2019, and February 2020. We used these estimates to assess the potential for sustained human-to-human transmission to occur in locations outside Wuhan if cases were introduced.Methods We combined a stochastic transmission model with data on cases of coronavirus disease 2019 (COVID-19) in Wuhan and international cases that originated in Wuhan to estimate how transmission had varied over time during January, 2020, and February, 2020. Based on these estimates, we then calculated the probability that newly introduced cases might generate outbreaks in other areas. To estimate the early dynamics of transmission in Wuhan, we fitted a stochastic transmission dynamic model to multiple publicly available datasets on cases in Wuhan and internationally exported cases from Wuhan. The four datasets we fitted to were: daily number of new internationally exported cases (or lack thereof), by date of onset, as of Jan 26, 2020; daily number of new cases in Wuhan with no market exposure, by date of onset, between Dec 1, 2019, and Jan 1, 2020; daily number of new cases in China, by date of onset, between Dec 29, 2019, and Jan 23, 2020; and proportion of infected passengers on evacuation flights between Jan 29, 2020, and Feb 4, 2020. We used an additional two datasets for comparison with model outputs: daily number of new exported cases from Wuhan (or lack thereof) in countries with high connectivity to Wuhan (ie, top 20 most at-risk countries), by date of confirmation, as of Feb 10, 2020; and data on new confirmed cases reported in Wuhan between Jan 16, 2020, and Feb 11, 2020.Findings We estimated that the median daily reproduction number (R-t) in Wuhan declined from 2.35 (95% CI 1.15-4.77) 1 week before travel restrictions were introduced on Jan 23, 2020, to 1.05 (0.41-2.39) 1 week after. Based on our estimates of R-t, assuming SARS-like variation, we calculated that in locations with similar transmission potential to Wuhan in early January, once there are at least four independently introduced cases, there is a more than 50% chance the infection will establish within that population.Interpretation Our results show that COVID-19 transmission probably declined in Wuhan during late January, 2020, coinciding with the introduction of travel control measures. As more cases arrive in international locations with similar transmission potential to Wuhan before these control measures, it is likely many chains of transmission will fail to establish initially, but might lead to new outbreaks eventually. Copyright (C) 2020 The Author(s). Published by Elsevier Ltd.