The signs, as they've been reported, are good. Dallas County's number of positive infections has, at worst, plateaued. At best, it is decreasing slightly. Despite the good news, North Texas officials, led by Dallas County Judge Clay Jenkins, are urging local residents to stay home, even as Texas' state government further loosens restrictions on movement, gathering and business throughout the state. One of the U.S. most prominent coronavirus infection models backs up Jenkins' concerns.
...do our celebrating w/ take-out & at home. If we’ll all make smart decisions, we can make it to a lower threat level where more opportunities for entertainment & commerce are open to us, and where less people are getting sick & dying. It’s up to all of us to flatten the curve.— Clay Jenkins (@JudgeClayJ) May 22, 2020
As measured by the models, the problem begins with Dallas County residents' continued lack of physical distancing.
According to a social distancing model created by the technology firm Unacast using anonymous data from cell phones and other web-connected devices, Dallas County hit its physical distancing peak in April, when residents reduced their average mobility by between 55 and 70%, as Texas has opened up and the pandemic has marched into its third month, Dallas County residents have gone back, in large part, to their pre-pandemic patterns.
On May 20, county residents reduced their average mobility by less than 25%. County residents failure to social distance has had scary effects on the Children's Hospital of Philadelphia's COVID-19 model for Dallas County.
The model, built by an interdisciplinary team from the hospital and the University of Pennsylvania, reflects the ongoing plateau, before projecting that Dallas County's case count could explode over the next month. By June 15, according to the model, daily cases in Dallas County could top 700.
"Social distancing was effective in preventing us from facing the same fate that New York did," Dr. Peter Hotez, co-director of the Center for Vaccine Development at Texas Children's Hospital and dean of the National School of Tropical Medicine at the Baylor College of Medicine in Houston, told the Observer last week. "The models told us to maintain social distancing throughout the month of May, but we weren't prepared to do that ... What I think will happen is that we'll see that exponential curve stay flat for a few weeks and then take off."
Projections released by UT-Southwestern on May 20 are a little more optimistic, but still show the potential for a harrowing summer. Researchers from the medical school estimate that Dallas County's coronavirus prevention measures are about 63% effective.
At that rate, UT-Southwestern's model predicts, Dallas County's COVID-19 cases will begin increasing in a linear fashion, reaching 400 cases a day in July and 600 cases a day in October. If Dallas County's measures dip to 58% effectiveness, the county could reach 800 cases a day by July. If county residents upped the effectiveness of the mitigation measures to 65%, the model says, Dallas County could see a progressive decrease in total cases over the rest of the year.
"We don't know if there might be mitigating effects from sunlight and heat. That might help, but we don't know that for sure," Hotez says. "I'm worried for the nation because a lot of cities like Dallas and Houston could see a big increase in the fall and it could be very destabilizing time right before the election."