The Covid-19 outbreak in Spain. A simple dynamics model, some lessons, and a theoretical framework for control response
The Covid-19 outbreak in Spain. A simple dynamics model, some lessons, and a theoretical framework for control response
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DOI：
10.1016/j.idm.2020.08.010
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发表时间：
2020-01-01
影响因子：
8.8
通讯作者：
Guirao, Antonio
中科院分区：
文献类型：
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作者：
Guirao, Antonio
西班牙是受新冠肺炎疫情影响最严重的国家之一，是每百万居民中感染率和死亡率最高的国家之一。于二零二零年一月底报告首次阳性结果。3月中旬，随着7,000例确诊病例，全国范围内实施了封锁。5月中旬，疫情稳定，政府放松了措施。在这里，我们在整个跨度在西班牙的流行病的动态模型，并研究控制措施的有效性。该模型也适用于意大利和德国。我们提出的公式可以很容易地估计疫情的规模和早期干预的好处。采用一个传染病恢复（SIR）模型来模拟该流行病。通过每日病例的最小均方拟合来估计生长和传播率、倍增时间和繁殖数量。时间序列数据来自政府官方报告。我们预测了不同有效性情景下封锁后的疫情曲线，并通过滑动平均滑动窗口对疫情趋势进行了预测。指数增长的表达式。暴发进展仍处于早期生长动态下。西班牙的基本繁殖数为2.5 +/- 0.1（95% CI 2.3 - 2.7），倍增时间为2.8 +/- 0.1天（95% CI 2.6-3.0）。措施有效性的微小变化会导致流行病规模的巨大差异。西班牙的有效性为68%，高于控制阈值（60%）。在封锁期间，生殖数量下降至平均0.81 +/- 0.02（95% CI 0.77-0.85）。估计疫情规模约为30万例。提前7天采取措施，减少到38%。西班牙的情况与其他国家类似。必须采取强有力的封锁措施，如果不能通过快速发现和隔离患者来弥补，哪怕稍微放松，也会使繁殖数量超过1。通过简单的计算，就可以根据采取措施的时间及其效果预测这一流行病的规模。西班牙行动迟缓。面对流行病，必须立即实施控制措施。(c)2020年，任作家。Elsevier B. V.代表KeAi Communications Co.制作和主持，公司
Spain is among the countries worst hit by the Covid-19 pandemic, with one of the highest rate of infections and deaths per million inhabitants. First positive was reported on late January 2020. Mid March, with 7,000 confirmed cases, nationwide lockdown was imposed. Mid May the epidemic was stabilized and government eased measures. Here we model the dynamics of the epidemic in Spain over the whole span, and study the effectiveness of control measures. The model is also applied to Italy and Germany. We propose formulas to easily estimate the size of the outbreak and the benefit of early intervention. A susceptible-infectious-recovered (SIR) model was used to simulate the epidemic. The growth and transmission rates, doubling time, and reproductive number were estimated by least-mean-square fitting of daily cases. Time-series data were obtained from official government reports. We forecasted the epidemic curve after lockdown under different effectiveness scenarios, and nowcasted the trend by moving average sliding window. Exponential growth expressions were derived. Outbreak progression remained under the early growth dynamics. The basic reproductive number in Spain was 2.5 +/- 0.1 (95% CI 2.3 -2.7), and the doubling time was 2.8 +/- 0.1 days (95% CI 2.6-3.0). Slight variations in measures effectiveness produce a large divergence in the epidemic size. The effectiveness in Spain was 68%, above control threshold (60%). During lockdown the reproductive number dropped to an average of 0.81 +/- 0.02 (95% CI 0.77-0.85). Estimated epidemic size is about 300,000 cases. A 7-days advance of measures yields a reduction to 38%. The dynamics in Spain is similar to other countries. Strong lockdown measures must be adopted if not compensated by rapid detection and isolation of patients, and even a slight relaxation would raise the reproductive number above 1. Simple calculations allow anticipating the size of the epidemic based on when measures are taken and their effectiveness. Spain acted late. Control measures must be implemented immediately in the face on an epidemic. (c) 2020 The Authors. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.