College of Computer Science, Sichuan University, Chengdu, China.
Department of Epidemiology and Biostatistics, School of Public Health, Indiana University Bloomington, Bloomington, Indiana, United States of America.
PLoS Comput Biol. 2020 Dec 28;16(12):e1008467. doi: 10.1371/journal.pcbi.1008467. eCollection 2020 Dec.
In January 2020, a COVID-19 outbreak was detected in Sichuan Province of China. Six weeks later, the outbreak was successfully contained. The aim of this work is to characterize the epidemiology of the Sichuan outbreak and estimate the impact of interventions in limiting SARS-CoV-2 transmission. We analyzed patient records for all laboratory-confirmed cases reported in the province for the period of January 21 to March 16, 2020. To estimate the basic and daily reproduction numbers, we used a Bayesian framework. In addition, we estimated the number of cases averted by the implemented control strategies. The outbreak resulted in 539 confirmed cases, lasted less than two months, and no further local transmission was detected after February 27. The median age of local cases was 8 years older than that of imported cases. We estimated R0 at 2.4 (95% CI: 1.6-3.7). The epidemic was self-sustained for about 3 weeks before going below the epidemic threshold 3 days after the declaration of a public health emergency by Sichuan authorities. Our findings indicate that, were the control measures be adopted four weeks later, the epidemic could have lasted 49 days longer (95% CI: 31-68 days), causing 9,216 more cases (95% CI: 1,317-25,545).
2020 年 1 月，中国四川省发现了 COVID-19 疫情。六周后，疫情得到了成功控制。本研究旨在描述四川疫情的流行病学特征，并估计干预措施对限制 SARS-CoV-2 传播的影响。我们分析了 2020 年 1 月 21 日至 3 月 16 日期间该省报告的所有实验室确诊病例的患者记录。为了估计基本繁殖数和日繁殖数，我们使用了贝叶斯框架。此外，我们还估计了实施控制策略所避免的病例数。该疫情导致 539 例确诊病例，持续时间不到两个月，并且在 2 月 27 日之后没有发现进一步的本地传播。本地病例的中位年龄比输入性病例大 8 岁。我们估计 R0 为 2.4（95%CI：1.6-3.7）。在宣布四川卫生紧急状态后三天，疫情在低于流行阈值后持续了约 3 周，然后自行维持。我们的研究结果表明，如果控制措施推迟四周实施，疫情可能会延长 49 天（95%CI：31-68 天），导致 9216 例更多的病例（95%CI：1317-25545）。
