Mask wearing could have saved up to 55,000 American lives: study

Mandated mask wearing in public could have saved 17,000 to 55,000 lives of US citizens who died by Covid-19 this past spring, according to a study.

The research, co-authored by an MIT professor and posted on the MedRxiv preprint server in July, identified the impact of mask mandates by comparing the before-and-after figures on cases and deaths in states that implemented such policies at different times.

“It is a very effective policy that includes relatively little economic disruption,” said Victor Chernozhukov, a professor in the Department of Economics and the Statistics and Data Science Centre at MIT, and one of the authors of the paper detailing the results. “We found it produced a considerable reduction in fatalities.”

The researchers estimated that imposing a national mandate on April 1 would have reduced the number of deaths by 40%, with a confidence interval of 90%, between then and June 1 after accounting for factors like population density, age and health of state residents, and additional responses to the pandemic in each state,

The study also found that in the same time frame, the total number of Covid-19 cases in the United States would have likely been 80% higher without the stay-at-home orders implemented by the vast majority of states.

"With a 90% confidence interval, that means the orders prevented an additional 500,000 to 3.4 million cases," the research stated

The researchers evaluated how much the reduction in activities like commuting and shopping trips has followed specific state policies, and how much has stemmed from personal decisions. They conclude that these factors are about equally responsible.

The paper has not yet been peer-reviewed, but the researchers are continuing to analyse these issues. “We hope to produce another paper that focuses on the effects of mask mandates during the reopening phase,” Chernozhukov said.

The study was originally appeared in Technology Review