Many people in Wisconsin — too many, public health experts say — are on the move.
At least that’s what data from millions of anonymized cellphone records show.
In March, amid a stay-at-home mandate, more Wisconsinites than ever were staying home all day, according to data from several location analytics companies.
But by September, Wisconsinites had largely returned to their pre-pandemic habits. And even as cases have spiked this fall, Wisconsinites have only slightly reduced their trips outside the home, the data show.
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Unacast, a location data analytics company based in Norway and New York, publishes a social distancing scoreboard that grades states based on how well their residents have reduced travel and avoided gathering in groups.
As of Thursday, Wisconsin scored a C- based on the fact that residents achieved a 40% to 55% reduction in average distance traveled, a less than 55% reduction in nonessential visits and an 82% to 94% reduction in encounters with others compared to the national baseline.
Wisconsinites were faring much better in the spring, when the state received a B grade. The U.S. as a whole currently scores a D. Michigan rates a D+ and Illinois a D-.
“We continue to see people who are throwing in the towel and have given up,” said Jeff Pothof, a physician and chief quality officer for UW Health.
Pothof said people may be tired of social distancing and mask-wearing, and seeing friends or family recover from COVID-19 can make it seem like the disease is not that dangerous.
“I wish we could show them what we see, which are the large number of people who aren’t doing OK,” Pothof said. “They’re actually doing pretty awful, and we’re not sure they’re going to make it.
“And it’s not just a couple people here and there. It’s such a large number of people that we’re having trouble keeping up with the pace, even hospitals as large as University of Wisconsin,” he added. “It’s really pretty frightening.”
Wisconsin, and the Midwest in general, is seeing record-breaking growth in coronavirus cases, overwhelming local hospitals and public health departments.
As of Friday, the state health department reported nearly 345,000 cases of COVID-19. On Tuesday, the health department reported a record number of coronavirus deaths — 92 people in one day.
Those numbers have been surging since September with little sign of slowing down.
Hospitals and public health officials have begged the public to stay home for the holidays and avoid gathering with anybody outside of their immediate household. On Thursday, the Centers for Disease Control and Prevention advised people not to travel for Thanksgiving due to the rise in cases.
Ajay Sethi, an infectious disease expert with the University of Wisconsin-Madison, said the cold weather, holidays and quarantine fatigue will make for a deadly mix this winter.
People’s experience over the summer, when warm weather incentivized people to gather outdoors and cases were not rising exponentially as they are now, may have given people “misguided optimism,” he said.
“You can get away with more in July than you can now,” Sethi said. “That could become reinforcing, like what I’m doing right now is fine. That stuff becomes habit-forming.”
Sethi and others pleaded with the public to stay home for the holidays and to only meet others outdoors, even in the cold.
“We still need to maintain our health protocols to the maximum,” he said.
University of Wisconsin-Madison professor Song Gao, who studies geospatial networks and mobility, made a mobility dashboard with data from several sources, including SafeGraph, a San Francisco-based company that pulls data from 45 million smartphone users around the U.S.
SafeGraph’s data shows people gradually moved more and more throughout summer. By September, Wisconsin residents were traveling nearly as much as they were in early March, before widespread community transmission was suspected.
So why didn’t cases spike in the summer like they are now? Gao suspects it’s because people were still avoiding close-quarters gatherings.
Measuring how far people travel doesn’t tell you whether they are also meeting up in groups. The proximity index — which measures how close two mobile devices get to each other — does.
And that number began surging in Wisconsin in September, Gao said. That coincides with the start of school and the onset of colder weather.
Whereas people in Wisconsin at one point reduced proximity to each other by 60% overall, by September and October, they had reduced proximity only by around 30%, according to Gao.
He suspects the increased number of close contacts is helping drive COVID-19 cases in Wisconsin to record numbers.
“Try to stay within your household,” Gao said. “Because that is based on the science. In this special period during the pandemic, we really need to behave more cautiously. The goal is to get out of this pandemic.”
Several studies have demonstrated the effectiveness of stay-at-home orders and social distancing on reducing the spread of COVID-19, including one that Gao and his colleagues published in the medical journal JAMA Network Open in September.
They found that across the country, people traveled less and stayed at home after stay-at-home mandates were issued in their state and that growth in COVID-19 cases appeared to slow after such orders were put in place.
But because of the exponential nature of COVID-19 transmission, the level of adherence is crucial to keeping rates down, experts said.
“You’ll see people say ‘we have masks on and clearly it doesn’t work.’ Well, it doesn’t work because we need really high compliance with it or the virus runs away,” Pothof said.
With the percentage of people testing positive in Wisconsin regularly topping 30% each day, even relatively safe places like grocery stores become more risky because the chance of interacting with a COVID-positive shopper is high.
“It just doesn’t take very much,” Pothof said. “With linear spread, you could probably make a case for 60% or 70% compliance to slow things down. With exponential spread, you need way tighter adherence, like 95% adherence. And we’re nowhere close to 95%.”
Some public health experts are pointing out that the use of cellphone data — even if anonymized — also brings up privacy and ethical considerations that researchers must grapple with.
Cellphone data has been widely available for years and mined by the business sector to understand people’s traffic patterns and optimize business. But it has not been used at this scale in public health before, said Sethi.
Sometimes, “technology outpaces the public discourse on whether we should be doing this stuff,” Sethi said. “Everything has to be done on a case-by case basis.”