Public Health and Preventive Medicine team publishes study revealing social distancing helped slow the spread of coronavirus in CNY
A team from the Department of Public Health and Preventive Medicine at Upstate Medical University has published a paper about a study showing how local social distancing slowed the spread of COVID-19 early in the pandemic.
The study used mobile phone tracking data from a company called Unacast to assess the relationship between people’s movements and the spread of the disease across eight Central New York counties. The paper, “Social Distancing Metrics and Estimates of SARS-CoV-2 Transmission Rates,” was published July 21 in the Journal of Public Health Management & Practice.
Its lead author, Christopher P. Morley, PhD, is chair of the Department of Public Health and Preventive Medicine at Upstate. During a six-week period from March 6 to April 15, Morley and his team looked at the data provided by Unacast, which has continued to publish a Social Distancing Scoreboard based on people’s mobile phone movements. Unacast assigns letter grades from “A” to “F” to counties across the country, including Central New York, for how much people are moving around based on their cell phone data. The grades were publicized locally this spring as public officials reminded people of lock-down orders to slow the spread of the coronavirus.
At the same time, Morley’s team was regularly calculating an R value for the region, with Upstate Public Health faculty member Dongliang Wang, PhD, adapting methods for the calculation of R to the rapidly changing COVID-19 context. The R value, or reproduction rate, is an indicator of the average number of new cases of an infectious disease are generated by an infected person. (R0 or “R naught,” is the baseline reproduction rate of a virus or other infectious agent, and R(t) is the estimated production rate at any given time, representing how the virus is behaving, as well as how well human interventions are working.) The researchers found strong associations between social distancing (the grade from Unacast) and the R value, Morley said.
“Using these data, we observed that each social distancing metric was statistically associated with the average R(t) for the week that followed,” according to Morley. “In short, the more people adhered to social distancing practices, the reproduction rate of the virus for the following week dropped (and conversely, poorer adherence led to higher R(t) estimates).”
The study included data from the following counties: Cayuga, Cortland, Herkimer, Madison, Oneida, Onondaga, Oswego and Tompkins. Morley authored an additional explanation of the study here.
“There were strong associations in each county,” Morley said. “It’s a crude measure, but provides insight and justification that while we were shut down, it had a beneficial effect on the spread of the virus. Is it the most perfect way to analyze it? Probably not. Is it the last word on the subject? Probably not. But was it what we needed to know at the time and it is evidence that the distancing had some impact.”
Morley said the study’s findings are especially important as the nation grapples with continually rising numbers of infections. Data that supports what actions were taken to slow the spread of coronavirus could be helpful for future policy decisions, he said.
“We still have societal debate about what is and isn’t necessary. We can’t get people to agree that masks are useful. Having data that supports societal shutdowns is even more important, if we have to go back there,” he said. “I think we do have to defend public health knowledge in the current climate. If we allow a narrative to exist that public health overshot, or got it wrong, we undermine faith in the recommendations. And the bottom line is, this is a dangerous time to do so.
“We need to be able to support what was done as an emergency measure and show that it worked because the next time we have to make a recommendation, we need to be able to say with some confidence that what we recommended last time had an impact as opposed to being an overreaction.”
Co-authors of the study are: Kathryn B. Anderson, MD, PhD, MSPH; Jana Shaw, MD, MPH, MS; Telisa Stewart, DrPH; Stephen J. Thomas, MD; and Dongliang Wang, PhD, all of Upstate.
Caption: Christopher P. Morley, PhD, is chair of the Department of Public Health and Preventive Medicine at Upstate Medical University.