英国牛津大学Nazrul Islam团队分析了社交疏离干预措施与covid-19发病率的关系。2020年7月15日，该成果发表在《英国医学杂志》上。

为了评估全球社交疏离干预措施与冠状病毒病2019（covid-19）发病率之间的关联，研究组根据欧洲疾控中心等的数据，对149个国家和地区的covid-19病例进行了一项间断时间序列分析的自然实验。

这些国家和地区在2020年1月1日至5月30日实施了五项社交疏离干预措施之一，包括关闭学校、工作场所和公共交通，限制集体聚会和公共活动以及限制行动（封城）等。对实施社交疏离干预措施前后covid-19的发病率比率（IRR）进行随机效应分析，使用数据截至2020年5月30日，或干预后30天。

平均而言，任何社交疏离干预措施的实施都会使covid-19发病率总体下降13％，IRR为0.87。当其他四项社交疏离干预措施到位时，关闭公共交通并不能进一步降低covid-19发病率。来自11个国家/地区的数据还表明，关闭学校、关闭工作场所以及限制群众聚会对疫情控制的总体有效性相差不大，IRR为0.85。在干预顺序方面，与其他社交疏离干预措施实施后延迟封城相比，更早封城使得covid-19发生率下降幅度更大。

总之，社交疏离干预措施可显著降低全球covid-19的发病率。当采取其他四项社交疏离措施时，关闭公共交通不会造成其他影响。较早实施封城可大大降低covid-19的发病率。

附：英文原文

Title: Physical distancing interventions and incidence of coronavirus disease 2019: natural experiment in 149 countries

Author: Nazrul Islam, Stephen J Sharp, Gerardo Chowell, Sharmin Shabnam, Ichiro Kawachi, Ben Lacey, Joseph M Massaro, Ralph B D’Agostino, Martin White

Issue&Volume: 2020/07/15

Abstract: Objective To evaluate the association between physical distancing interventions and incidence of coronavirus disease 2019 (covid-19) globally.

Design Natural experiment using interrupted time series analysis, with results synthesised using meta-analysis.

Setting 149 countries or regions, with data on daily reported cases of covid-19 from the European Centre for Disease Prevention and Control and data on the physical distancing policies from the Oxford covid-19 Government Response Tracker.

Participants Individual countries or regions that implemented one of the five physical distancing interventions (closures of schools, workplaces, and public transport, restrictions on mass gatherings and public events, and restrictions on movement (lockdowns)) between 1 January and 30 May 2020.

Main outcome measure Incidence rate ratios (IRRs) of covid-19 before and after implementation of physical distancing interventions, estimated using data to 30 May 2020 or 30 days post-intervention, whichever occurred first. IRRs were synthesised across countries using random effects meta-analysis.

Results On average, implementation of any physical distancing intervention was associated with an overall reduction in covid-19 incidence of 13% (IRR 0.87, 95% confidence interval 0.85 to 0.89; n=149 countries). Closure of public transport was not associated with any additional reduction in covid-19 incidence when the other four physical distancing interventions were in place (pooled IRR with and without public transport closure was 0.85, 0.82 to 0.88; n=72, and 0.87, 0.84 to 0.91; n=32, respectively). Data from 11 countries also suggested similar overall effectiveness (pooled IRR 0.85, 0.81 to 0.89) when school closures, workplace closures, and restrictions on mass gatherings were in place. In terms of sequence of interventions, earlier implementation of lockdown was associated with a larger reduction in covid-19 incidence (pooled IRR 0.86, 0.84 to 0.89; n=105) compared with a delayed implementation of lockdown after other physical distancing interventions were in place (pooled IRR 0.90, 0.87 to 0.94; n=41).

Conclusions Physical distancing interventions were associated with reductions in the incidence of covid-19 globally. No evidence was found of an additional effect of public transport closure when the other four physical distancing measures were in place. Earlier implementation of lockdown was associated with a larger reduction in the incidence of covid-19. These findings might support policy decisions as countries prepare to impose or lift physical distancing measures in current or future epidemic waves.

DOI: 10.1136/bmj.m2743

Source: https://www.bmj.com/content/370/bmj.m2743