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Physical distancing: it works, URMC research shows

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As the state relaxes business shutdown orders and employees return to their workplaces, physical distancing will still play an important role in society.

But a new preprint study from researchers at University of Rochester, Cornell University, and Lancaster University concludes that social distancing was very effective in stabilizing COVID-19 infection rates, though it likely won’t reduce infection rates on its own.

“Social distancing alone doesn’t seem to be getting us where we want to be,” said Aaron Wagner, a professor of electrical and computer engineering at Cornell University, and one of the report’s authors, during a video call with reporters Tuesday.

Elected and public health officials have emphasized physical distancing not to eliminate COVID-19, but to keep hospitals and health care systems from getting overwhelmed by an influx of patients needing care.

The scientists worked primarily with calculations around the doubling rate, or the number of days it takes for a state’s COVID-19 cases to double. They found that prior to taking steps such as closing schools and issuing stay-at-home orders, states’ cases were doubling approximately every three days. Post-intervention, the researchers calculated, it would take 100 days for cases to double.

Monroe County recorded its first confirmed COVID-19 case on March 12, and four days later it had 10 confirmed cases. When the shutdown orders took effect in earnest and people started staying home, on March 23 there were 156 confirmed cases. It would take six weeks, until May 3, for the number of cases to increase another tenfold to 1,569. The county now has roughly 1,850 cases.



The authors wrote that physical distancing efforts across states resulted in an estimated 55 percent reduction in contact between contagious and susceptible people. As a result, what were at one point rapidly rising rates of infection have flattened. But they haven’t contracted.

“This is a plateau that keeps it in our communities and keeps us at risk,” said Elaine Hill, an assistant professor of public health sciences at University of Rochester Medical Center and one of the report’s authors.

The plateaued infection rates leave government leaders little wiggle room as they look to reopen workplaces and public spaces, Hill added. For that reason, decision makers need to be very cautious and deliberate as they begin those efforts.

The persistently flat COVID-19 case numbers suggest “that existing social distancing measures will need to remain in place for some time,” the paper reads.

The question becomes which ones need to remain in place. Hill and Wagner said researchers should examine which measures and practices produce the greatest benefit. For example, is asking people to wear face coverings in public as effective as closing schools.

The authors also add that additional measures such as testing and contact tracing will likely reduce the infection doubling rate further.

Jeremy Moule is CITY's news editor. He can be reached at [email protected].

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