Sept. 22 (UPI) -- Encouraging voluntary social distancing may be more effective at containing the spread of COVID-19 than government "stay-at-home" mandates, according to an analysis of cellphone data published Tuesday by the journal PLOS ONE.
Since the start of the U.S. outbreak, Americans have been practicing social distancing voluntarily or because of governmental restrictions, or some combination of the two, according to researchers at Louisiana State University.
Maintaining physical distance from others can limit the spread of COVID-19, according to the U.S. Centers for Disease Control and Prevention.
Understanding the interplay of these two factors could help inform optimal strategies for encouraging social distancing and, ultimately, reduce disease spread, LSU researchers said.
"The relation between cellphone data and the disease is not straightforward, largely due to disease measurement issues that arise from the way individual jurisdictions track and report cases," study co-author Rajesh Narayanan told UPI.
In general, the findings "reveal that social distancing in the U.S. during the COVID-19 pandemic was initially voluntary rather than a response to governmental jurisdictional restrictions," said Narayanan, chair of the Department of Finance at LSU.
For this study, the researchers analyzed population location data across the country obtained via GPS pings from cellphones. The data was collected, and provided, anonymously, by the company SafeGraph.
It developed a computational model of social distancing behavior across the United States using the cellphone data to indicate the amount of time spent at home -- a "proxy" for social distancing -- in counties throughout the country.
On March 14, the day President Donald Trump declared a national emergency in response to the pandemic, approximately 25% of Americans were voluntarily staying home based on recommendations from state and national public health officials, the assessment of GPS location data revealed.
But the number of Americans who adhered to state stay-at-home orders increased nine-fold from the end of January, when the first cases of COVID-19 were reported in the United States, through the end of March as states implemented stay-at-home orders.
From early April through mid-June, though, when some states began to relax these measures, the percentage of Americans staying home declined by about 50%.
This relaxation of "stay-at-home" orders in some parts of the United States coincided with a rise of COVID-19 cases, with increases as much as 10-fold in some regions.
Overall, many COVID-19 "hotspots" in the spring were located in counties with low social distancing, the researchers said.
In addition, at least initially, people in counties with higher population densities -- where there is greater risk for disease spread -- were more likely than their counterparts in more rural areas to voluntarily practice social distancing and keep case counts low, according to the researchers.
"As the pandemic evolved in the U.S. [and mandated distancing was implemented], the variation in social distancing behavior increased ... producing hotspots with low social distancing and cold spots with high social distancing," Narayanan told UPI.
"The implication is that encouraging voluntary distancing could potentially be an effective and lower-cost alternative to governmental restrictions," he said.
"Such encouragement could boost acceptance of restrictions and thus increased compliance with distancing rules, resulting in an even greater degree of distancing."