Shutdown Orders Prevented an Estimated 530 Million COVID-19 Infections Worldwide

Two reports published in Nature argue that the global shutdown during the COVID-19 pandemic prevented hundreds of millions of cases of coronavirus and millions of deaths worldwide. Stay-at-home orders and other restrictions limited the spread of infection and prevented an estimated 530 million infections across 6 countries, including an estimated 60 million infections in the US, according to data from the University of California at Berkeley (UC Berkeley). A second study, from the Imperial College London, estimated the shutdowns saved about 3.1 million lives in 11 European countries.

The UC Berkeley study examined large-scale anti-contagion policies during the pandemic in six countries (China, the US, France, Italy, Iran, and South Korea) and was led by Solomon Hsiang, PhD, director of the university’s Global Policy Laboratory. The team used an econometric model to estimate how 1,717 interventions, such as stay-at-home orders and travel bans, altered the spread of the virus, examining infection rates before and after the interventions. The model estimates that the countries managed to avoid a combined 62 million test-confirmed infections. Since most people who become infected may not get tested, the actual number of cases averted is much higher, estimated at about 530 million across the six countries.

The team from the Imperial College looked at effects of non-pharmaceutical interventions across 11 European countries from the start of the pandemic until May 4, 2020. Their model uses data on observed deaths to calculate backwards and estimate transmission that occurred several weeks prior. They compared the estimates on viral spread to death totals to infer changes in the virus’ course resulting from policy interventions. They were then able to calculate about 3.1 million deaths prevented across the 11 countries.

“This is just the beginning of the epidemic: we’re very far from herd immunity,” Samir Bhatt, DPhil, the Imperial College study’s senior author, told The Washington Post. “The risk of a second wave happening if all interventions and precautions are abandoned is very real.”

“Without these policies employed, we would have lived through a very different April and May,” said Dr. Hsiang. “The whole point of this study is to help us understand what we got for this tremendous sacrifice that the country has gone through. Ultimately, whether or not it was worth it is something society has to decide.”

Sources: The Washington Post, June 8, 2020; Hsiang S, Allen D, Annan-Phan S, et al. The effect of large-scale anti-contagion policies on the COVID-19 pandemic. Nature. June 8, 2020; Flaxman S, Mishra S, Gandy A, et al. Estimating the effects of non-pharmaceutical interventions on COVID-19 in Europe. Nature. June 8, 2020.