Stay-at-home orders issued across the United States in the spring appeared to work at keeping people home, new cellphone data from the US Centers for Disease Control and Prevention shows.
"Based on location data from mobile devices, in 97.6% of counties with mandatory stay-at-home orders issued by states or territories, these orders were associated with decreased median population movement after the order start date," the researchers wrote in the study.
The researchers also found that in areas where orders were lifted or expired, movement "significantly increased" immediately afterward.
“Reduced population movement helps prevent close contact among persons outside the household, potentially limiting exposure to persons infected with SARS-CoV-2,” the researchers from the CDC and the Georgia Tech Research Institute wrote in the CDC’s weekly report.
The study included data on stay-at-home orders issued by states, the District of Columbia and five US territories between March 1 and May 31.
The researchers, from the CDC and the Georgia Tech Research Institute, examined those orders and analyzed anonymous location data from mobile devices. They used the location data to estimate movements by county, based on the percentage of devices that moved each day beyond 150 meters of its most common nighttime location, which the researchers assumed was the home.
Some people could have more than one mobile device, the researchers noted. Plus media attention around Covid-19 and the cancellation of events could also have influenced people to stay home.
"These findings can inform future public policies to reduce community spread of COVID-19,” the researchers wrote.