CORONAVIRUS PANDEMIC UPDATE: STUDY SHOWS SOCIAL DISTANCING MEASURES SAVED LIVES
NATURE – Monday, June 8, 2020
TITLE: The Effect of Large-Scale Anti-Contagion Policies on the COVID-19 Pandemic
AUTHORS: Solomon Hsiang, Daniel Allen, Sébastien Annan-Phan, Kendon Bell, Ian Bolliger, Trinetta Chong, Hannah Druckenmiller, Luna Yue Huang, Andrew Hultgren, Emma Krasovich, Peiley Lau, Jaecheol Lee, Esther Rolf, Jeanette Tseng & Tiffany Wu
BACKGROUND: Governments around the world are responding to the novel coronavirus (COVID-19) pandemic with unprecedented policies designed to slow the growth rate of infections. Many actions, such as closing schools and restricting populations to their homes, impose large and visible costs on society, but their benefits cannot be directly observed and are currently understood only through process-based simulations.
METHOD: Here, we compile new data on 1,717 local, regional, and national non-pharmaceutical interventions deployed in the ongoing pandemic across localities in China, South Korea, Italy, Iran, France, and the United States (US). We then apply reduced-form econometric methods, commonly used to measure the effect of policies on economic growth, to empirically evaluate the effect that these anti-contagion policies have had on the growth rate of infections.
RESULTS: Our empirical results indicate that large-scale anti-contagion policies are slowing the COVID-19 pandemic. Because infection rates in the countries we study would have initially followed rapid exponential growth had no policies been applied, our results suggest that these policies have provided large health benefits. For example, we estimate that there would be roughly 465× the observed number of confirmed cases in China, 17× in Italy, and 14× in the US by the end of our sample if large-scale anti-contagion policies had not been deployed. Consistent with process-based simulations of COVID-19 infections, our analysis of existing policies indicates that seemingly small delays in policy deployment likely produced dramatically different health outcomes.
Some policies have different impacts on different populations, but we obtain consistent evidence that the policy packages now deployed are achieving large, beneficial, and measurable health outcomes. We estimate that across these six countries, interventions prevented or delayed on the order of 62 million confirmed cases, corresponding to averting roughly 530 million total infections.
SUMMARY: These findings may help inform whether or when these policies should be deployed, intensified, or lifted, and they can support decision-making in the other 180+ countries where COVID-19 has been reported.