Lockdowns stopped more than 500 million COVID-19 infections

Effective lockdown measures due to COVID-19 pandemic in 6 major countries have substantially slowed the spread of the novel coronavirus by stopping more than 500 million infections, according to a research from UC Berkeley team.

COVID-19 infections started in late 2019 in Wuhan, China, and within a matter of weeks, spread around the globe. The health risks posed by the virus also resulted in a devastating economic recession. With more than 7.3 million cases and more than 400,000 deaths worldwide the pandemic is still causing havoc in most parts of the world. Lockdown measures implemented in some countries resulted in reducing the transmission of COVID-19 infections, according to 2 new studies published in Nature journal.

According to UC Berkeley researchers, lockdown prevented 531 million infections across 6 countries – Iran, South Korea, China, France, Italy, and the United States. While scientists at the Imperial College London estimate that the lockdown measures saved about 3.1 million lives across 11 European countries.

Preventing more than 500 million COVID-19 infections

Across 6 countries, effective interventions prevented as many as 62 million confirmed coronavirus cases, which in turn helped avert almost 530 million infections. UC Berkeley researchers studied the impact of 1,700 local, regional and national public health policies that slowed down COVID-19 infections. To achieve this, the researchers analyzed and correlated growth rate of infections within hundreds of regions before and after each of these policies was implemented locally. The public health policy measures included; restriction of travel, social distancing through suspension of events, commercial, educational, and religious activities, quarantines, lockdown, as well as deceleration of emergency form January to April 6, 2020.

According to their estimations, if lockdown measures and policies had not been deployed, there would be roughly 465 times the observed number of confirmed cases in China, 17 times in Italy and 14 times in the United States. The estimates suggests that there would have been 285 million total COVID-19 infections in China, if preventive measures were not taken.

The researcher analyzed data as per the number of confirmed cases in each country, based on local testing procedures. But to account for limited testing, they also calculated what the total infection rates likely would have been if everyone had been tested. The impact of preventive measures and policies in six countries is striking, both in statistical and human terms:

  • China: policies and interventions prevented roughly 37 million more confirmed cases, corresponding to 285 million total cases (including confirmed cases)
  • South Korea: 11.5 million confirmed cases and 38 million total cases prevented
  • United States: 4.8 million confirmed cases and 60 million total cases prevented
  • Iran: 5 million confirmed cases and 54 million total cases prevented
  • Italy: 2.1 million confirmed cases and 49 million total cases prevented
  • France: 1.4 million confirmed cases and 45 million total cases prevented
COVID-19 infections map
Image Credit: UC Berkeley (Global Policy Lab)
Map showing how preventive measured decreased the spread of COVID-19 infections

The team led by Dr. Solomon Hsiang concluded in their study that self quarantine at home, closure of commercial businesses and lockdowns produced the clearest benefits. Restrictions on travel restrictions and other types of bans on social gathering had mixed results, with large effects in some countries — Iran and France, respectively, and less clear benefits in countries such as the US.

The researchers did not discover strong evidence regarding the closure of schools and its impact on COVID-19 cases in any country, as they cautioned that their finding is not conclusive, and more research work is to be done to inform school policies. The team found that while some policies resulted in a sudden behavioral change and could have led to small benefits, it took three weeks, in general, for policies to achieve their full impact on the spread of COVID-19.

“The last several months have been extremely difficult since the COVID-19 spread around the world, but through sacrifices, people throughout the world have each contributed to one of humanity’s greatest collective achievements”, said Dr. Solomon, the lead author of the study.

“I don’t think any human endeavor has ever saved so many lives in such a short period of time. Thanks to science and cooperation, we changed the course of history.”

“Many people suffered tragic losses, and it would have been more disastrous if we had done nothing, the death toll would have been really high,” said Dr. Hsiang.

Solomon Hsiang, director of Berkeley’s Global Policy Laboratory and Chancellor’s Professor at the Goldman School of Public Policy, describes the life-saving impact of emergency pandemic policies in six countries. (UC Berkeley video by Roxanne Makasdjian)

The UC Berkeley research team formulated its conclusions on extensive data collection, acquired from hundreds of sources in different languages. From tracking the origin of COVID-19 in a given country, to tracking the growth og infections over time. Lessons from this study can be useful to more than 180 countries, that were exempted from the analysis. While some countries have reduced the COVID-19 infection rates, other countries, such as Bangladesh, Nepal, India, Pakistan, Peru, Mexico, Brazil, Afghanistan, and Nigeria – are just starting to take off.

Preventing 3.1 million COVID-19 deaths in Europe

Scientists from the Imperial College London suggest that the lockdown measures imposed in Europe have significantly reduced the spread of the corona virus, and helped in saving millions of lives. The research was focused on 11 European countries and data was collected up to early May 2020. The countries included in the study were ; Sweden, Denmark, Norway, Italy, France, Belgium, Spain, Austria, Germany, UK and Switzerland.

European countries started implementing emergency non-pharmaceutical measures (such as closing schools, and lockdowns) to counter COVID-19 since March 2. To determine the effectiveness of these non-pharmaceutical interventions is important to define what courses of action are required in future to control the health risk as well as to improve the socio-economic conditions amid the pandemic.

The research team estimated the reproduction number (average number of COVID-19 cases an infected person is likely to cause during their infection period). However, the reproduction number could be complicated to determine using case data, as majority of the infectious population is likely to go unreported. To tackle this issue the team used death data by calculating infection levels based on reported deaths, up until May 4, 2020.

The team estimated that by May 4, 2020, 12 to 15 million individuals in 11 European countries had been infected with COVID-19 (3.2 to 4% population, with large country-to-country variations). Data from the observed deaths against those predicted by the model (absence of interventions), the research suggests that almost 3.1 million deaths have been avoided due to non-pharmaceutical measures. According to the study, the reproduction number has dropped below one due to these interventions, decreasing by an average of 82% (with country-to-country variations).

“The data shows that without any intervensions like closure of schools and lockdowns there would have been more deaths from COVID-19 in Europe” said Dr Samir Bhatt, a co-author of the study. Careful considerations should now be given to the existing measures and interventions that are required to keep COVID-19 transmission under control.”

Read More: Researchers create biodegradable medical masks for COVID-19


Emergency COVID-19 measures prevented more than 500 million infections, study finds
Edward Lempinen | June 8, 2020 | University of California, Berkeley, USA

Lockdown and school closures in Europe may have prevented 3.1m deaths
Kate Wighton | June 8, 2020 | Imperial College London, UK


The effect of large-scale anti-contagion policies on the COVID-19 pandemic

Estimating the effects of non-pharmaceutical interventions on COVID-19 in Europe


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