More than 1 million US Covid-19 cases and more than 59,000 deaths could have been prevented by early May if mitigation steps had been implemented two weeks earlier, according to a modeling study published Friday in Science Advances.
Sen Pei, a research scientist at the Columbia University Mailman School of Public Health, and colleagues built a Covid-19 transmission model that looked at all US counties from February 21 through May 3.
Broad coronavirus transmission control measures were announced March 15, they wrote. The study found that starting interventions such as social distancing and business closures a week earlier, on March 8, led to 600,000 fewer confirmed cases and 32,000 fewer deaths. Beginning such interventions two weeks earlier, on March 1, resulted in more than 1 million fewer confirmed cases and more than 59,000 fewer deaths.
Pei and colleagues wrote that they recognize that protracted shutdowns are a burden, but said it’s vital to balance a return to social and economic activity with avoidance of viral spread. South Korea, Vietnam, New Zealand and Germany “have shown that such a balance may be achievable; the strategies adopted in these countries could be used to guide policies in the US and elsewhere.”
“Our results demonstrate the dramatic impact that earlier interventions could have had on the COVID-19 pandemic in the US,” the authors wrote. “Looking forward, the findings underscore the need for continued vigilance when control measures are relaxed.”
And, they write, “rapid detection of increasing case numbers and fast re-implementation of control measures is needed to control rebound outbreaks of COVID-19.”
The researchers note their experiments are based on idealized assumptions. It’s complicated to initiate and implement social distancing rules during an outbreak, and compliance might lag, they write.
But, “given that more effective control of COVID-19 has been maintained to date in countries such as South Korea, New Zealand, Vietnam and Iceland, these cases and deaths could have been averted, not merely postponed.”