Infectious Disease Service, Department of Paediatrics, KK Women's and Children's Hospital, 100 Bukit Timah, Singapore229899, Singapore.
Duke-NUS Medical School, Academia, 20 College Road, Level 6, Room 60, Singapore169856, Singapore.
Epidemiol Infect. 2020 Dec 9;148:e301. doi: 10.1017/S0950268820002964.
The epidemiological target of lockdowns is to drive down the effective reproduction number (Rt) to less than 1. A key unknown is the duration that lockdowns need to be in place to achieve this and which lockdown measures are effective. Daily number of laboratory confirmed community coronavirus 2019 cases were extracted from regular reports from the Ministry of Health Singapore from 20 March 2020 to 4 May 2020. We generated daily Rt to estimate the time needed for these public health lockdown measures to control the spread of severe acute respiratory syndrome coronavirus 2 as demonstrated by Rt < 1. It took about 14 days of nationwide lockdown for the Rt trend to change and start falling. The upper limit of the 95% confidence interval for time to Rt < 1 was day 15 of lockdown. We have shown that it is possible to start 'bending the Rt curve' about 2 weeks after implementation of specific lockdown measures with strict compliance.
封锁的流行病学目标是将有效繁殖数（Rt）降低到 1 以下。一个关键的未知数是实现这一目标需要封锁多长时间，以及哪些封锁措施是有效的。从 2020 年 3 月 20 日至 2020 年 5 月 4 日，我们从新加坡卫生部的定期报告中提取了实验室确诊的社区 2019 年冠状病毒每日病例数。我们生成了每日 Rt，以估计这些公共卫生封锁措施需要多长时间才能控制严重急性呼吸系统综合征冠状病毒 2 的传播，如 Rt < 1 所示。全国范围的封锁大约需要 14 天，Rt 趋势才开始下降。Rt < 1 的时间上限为封锁的第 15 天。我们已经表明，在严格遵守的情况下，实施特定封锁措施大约两周后，就有可能开始“使 Rt 曲线弯曲”。
