Chicago officials are still using cell phone location data to track COVID patterns, the city's top doctor revealed Thursday, which suggests different information from last year.
Chicago Department of Public Health Commissioner Dr. Allison Arwady said the city does not track residents' individual locations, but rather cell phone movement patterns across the area.
Based on the city's latest data, Arwady said more Chicagoans are staying home during the day compared to last year. She added that in the evening over the past few weeks, more residents are "out and about" and moving around.
"I think, you know, this just reflects that people are excited for the warm weather, feeling good about vaccine and I think just sort of wishing that COVID was over," Arwady said.
Last year, cell phone data showed that people across the city were at home throughout the day a little more than half of the time. Once social distancing guidelines and the statewide stay-at-home order took effect, that number jumped to nearly 80%.
Arwady said last April that the city was working with health data company BlueDot to use anonymous location data from cell phones across the city to track movements.
She noted the data is collected from apps where users have agreed to let an app "use my location data."
Here's how it works:
"What you do is you say, 'We're going to look back over the last six months. What's the location that this device is in between midnight and 9 a.m.? The most, we're going to assume that is home. And then we ping every half hour through the day to see how far is that cell phone from home?" Arwady said. "Again, not an individual-level data, but it lets us see are we actually seeing changes? It's not perfect. It's not everybody. We know people leave without their cell phones. We know everybody doesn't have cell phones."
Although COVID vaccinations continue throughout the city, Chicago saw an uptick of reported daily coronavirus cases Thursday at 519, which is up 41% from the prior week, based on city data.
Chicago officials also reported the city's seven-day rolling positivity rate was sitting at 4.6%, which is an increase from 3.4% last week.
Speaking at a press availability on Wednesday, Chicago Mayor Lori Lightfoot says that the daily number of new cases in the city has more than doubled in recent weeks, saying that any further loosening of coronavirus restrictions will have to be paused as a result.
Lightfoot says the trend is largely “being driven by adults ages 18 to 39” in the city, and cited four different neighborhoods as largely driving the surge, including Lincoln Park, Old Town, Dunning and Portage Park.
Both Lightfoot and Arwady urged are urging residents this week, especially younger ones, to continue to adhere to social distancing protocols and to wear their masks in public, saying that the end of the pandemic could be in sight if residents continue to stay vigilant.