IT Power Services GmbH, Modecenterstraße 14/3, A-1030, Vienna, Austria.
Faculty of Psychology, University of Vienna, Liebiggasse 5, A-1010, Vienna, Austria.
BMC Public Health. 2021 Jul 28;21(1):1472. doi: 10.1186/s12889-021-11530-0.
During the initial phase of the global COVID-19 outbreak, most countries responded with non-pharmaceutical interventions (NPIs). In this study we investigate the general effectiveness of these NPIs, how long different NPIs need to be in place to take effect, and how long they should be in place for their maximum effect to unfold.
We used global data and a non-parametric machine learning model to estimate the effects of NPIs in relation to how long they have been in place. We applied a random forest model and used accumulated local effect (ALE) plots to derive estimates of the effectiveness of single NPIs in relation to their implementation date. In addition, we used bootstrap samples to investigate the variability in these ALE plots.
Our results show that closure and regulation of schools was the most important NPI, associated with a pronounced effect about 10 days after implementation. Restrictions of mass gatherings and restrictions and regulations of businesses were found to have a more gradual effect, and social distancing was associated with a delayed effect starting about 18 days after implementation.
Our results can inform political decisions regarding the choice of NPIs and how long they need to be in place to take effect.
在全球 COVID-19 爆发的初始阶段，大多数国家都采取了非药物干预措施（NPIs）。在这项研究中，我们调查了这些 NPIs 的总体效果，不同的 NPIs 需要多长时间才能生效，以及它们需要多长时间才能达到最大效果。
我们使用全球数据和一种非参数机器学习模型来估计 NPIs 的效果与其实施时间的关系。我们应用随机森林模型并使用累积局部效应（ALE）图来得出与实施日期有关的单一 NPIs 的有效性估计。此外，我们使用自举样本来研究这些 ALE 图的可变性。
我们的结果表明，关闭和规范学校是最重要的 NPI，大约在实施后 10 天就会产生明显的效果。限制群众集会、限制和规范企业被发现具有更渐进的效果，而社会隔离则在实施后约 18 天开始产生延迟效果。
我们的研究结果可以为政治决策提供信息，包括选择 NPIs 以及它们需要多长时间才能生效。
