Coronavirus Lockdowns Substantially Slowed the Pandemic, Research Says

New research shows that the restrictive measures taken around the world to slow the spread of the coronavirus have delivered considerable health benefits.

Public health measures including social distancing and lockdowns have prevented more than 500 million additional coronavirus infections in six countries, according to the peer-reviewed study published in the journal Nature.

Researchers from the University of California at Berkeley analyzed policies and results in the six countries of China, France, Iran, Italy, South Korea and the United States.

“[W]e find that the deployment of anti-contagion policies in all six countries significantly and substantially slowed the pandemic,” the researchers write in their paper. Solomon Hsiang is the lead author on the Nature article titled, “The effect of large-scale anti-contagion policies on the COVID-19 pandemic.”

They estimate that across these six countries, interventions prevented or delayed as many as 62 million confirmed coronavirus cases, which in turn helped avert roughly 530 million total infections.

The researchers measured how much 1,700 local, regional and national public health policies slowed the growth rate of infections. To do this, they compared the growth rate of infections within hundreds of regions before and after each of these policies was implemented locally.

They estimate that if large-scale anti-contagion policies had not been deployed, there would be roughly 465 × the observed number of confirmed cases in China; 17 × in Italy; and 14 × in the U.S.

Their central estimates suggest that there would be roughly 37 million more cumulative confirmed cases (corresponding to 285 million more total infections, including the confirmed cases) in China had preventive measures not been taken.

The U.S. would have had 4.8 million more confirmed cases (60 million total infections) had it never enacted any anti-contagion policies.

For other countries: there would have been 11.5 million more confirmed cases in South Korea (38 million total infections); 2.1 million more confirmed cases in Italy (49 million total infections); 5 million more confirmed cases in Iran (54 million total infections) and 1.4 million more confirmed cases in France (45 million total infections).

The author notes that societies are trying to weigh the health benefits of anti-contagion policies when the social and economic costs are clearly seen in increases unemployment and disruptions to education. “It is therefore not surprising that some populations have hesitated before implementing such dramatic policies, especially when their costs are visible while their health benefits – infections and deaths that would have occurred but instead were avoided or delayed – are unseen,” the article says.

The results reflect when anti-contagion policies were implemented as well as how many localities deployed them and for how long. The researchers found that “seemingly small delays in policy deployment likely produced dramatically different health outcomes.”

The policy deployments measured included travel restrictions; social distancing through cancellations of events and suspensions of educational, commercial and religious activities; quarantines and lockdowns; and additional policies such as emergency declarations and expansions of paid sick leave, from the earliest available dates to April 6, 2020.

The article was accelerated for publication by Nature and is still subject to a final proofreading and editing.

Researchers on the project from the Global Policy Laboratory, Goldman School of Public Policy, UC Berkeley, Berkeley, USA include: 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 and Tiffany Wu.

Insurance Journal reported on an earlier report titled, “Strong Social Distancing Measures in the United States Reduced the COVID-19 Growth Rate” found that steps taken to reduce the spread of coronavirus in the U.S. by state and local governments have had a major impact. The results imply that by April 27, the number of cases would have been 35 times higher without any of the measures — suggesting the U.S. would have reported 35 million (rather than 1 million) COVID-19 cases. The report was published in Health Affairs.

This study evaluated the impact of four measures take from March 1 to April 27 — bans on large social gatherings, public school closures, the shuttering of entertainment-related businesses and shelter-in-place orders. The authors found the closing of entertainment businesses — such as restaurants, movie theaters and gyms — and shelter-in-place orders resulted in a dramatic reduction in COVID-19 cases. However, the study determined the other two measures — bans on large gatherings and school closures — had a less significant impact.