Some Georgia restaurants reopened for dine-in service on April 27 as the state continued to relax coronavirus restrictions. Many others chose to remain closed. (Video: The Washington Post)

One week after Georgia allowed dine-in restaurants, hair salons and other businesses to reopen, an additional 62,440 visitors arrived there daily, most from surrounding states where such businesses remained shuttered, according to an analysis of smartphone location data.

Researchers at the University of Maryland say the data provides some of the first hard evidence that reopening some state economies ahead of others could worsen and prolong the spread of the novel coronavirus. Any impetus to travel, public health experts say, increases the number of people coming into contact with each other and raises the risk of transmission.

“It’s exactly the kind of effect we’ve been worried about,” said Meagan Fitzpatrick, an assistant professor at the University of Maryland School of Medicine.

“This is not an unpredictable outcome with businesses opening in one location and people going to seek services there,” said Fitzpatrick, who has reviewed the findings by the university’s Maryland Transportation Institute.

In the week after Georgia businesses reopened April 24, a total daily average of 546,159 people traveled there from other states. That included 62,440 more trips daily than in the week before the reopenings — a 13 percent increase, said Lei Zhang, the lead researcher and institute's director. The trips were measured using anonymized location data in smartphone apps.

The vast majority — 92 percent — came from four adjacent states: Alabama, South Carolina, Tennessee and Florida.

At the time, Alabama, South Carolina and Tennessee had started to allow most “nonessential” retail stores to reopen, with limitations and requirements to continue social distancing. Tennessee also had begun to allow gyms and most sit-down restaurants to reopen. However, only Georgia had permitted the reopening of dine-in restaurants, gyms, hair salons, barbershops and entertainment venues, such as bowling alleys and movie theaters.

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Zhang said the analysis does not yet show where people went in Georgia, though he predicts most were probably personal trips, rather than for work, because many employers had yet to reopen by May 1.

“I don’t think all of them were going to the barbershop,” he said. “But it seems people are traveling there for things they can’t do, or for business that aren’t open, in their own state.”

For example, Zhang said, the biggest jump — 17 percent — came from Florida, where some beaches had reopened but most businesses deemed unessential remained closed until this week.

As about half of states have started to lift business restrictions, the researchers say their findings underscore the potential dangers of doing so piecemeal in a country where people regularly cross state lines for work and leisure. In densely populated places such as the New York tri-state area and the Washington metropolitan region, many residents live in one state, work in a second and routinely attend evening or weekend outings in a third.

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The findings are likely to resonate following Virginia Gov. Ralph Northam’s (D) announcement Monday that he hopes to begin allowing dine-in restaurants, retailers, gyms and hair salons to reopen, with safety requirements, starting May 15.

Maryland Gov. Larry Hogan (R) announced Wednesday that he was reopening state beaches for exercise, allowing elective medical procedures to resume, and permitting some outdoor activities such as golf, tennis and boating. However, he has said, the state’s number of new hospitalizations and intensive care unit patients must either consistently plateau or decline before stay-at-home measures can be lifted.

D.C. Mayor Muriel E. Bowser (D) has said she has no time frame for reopening, saying the city first must see a sustained drop in new cases and rates of infection.

Northam (D) said Wednesday that he would allow local leaders in covid-19 “hot zones,” such as densely populated Northern Virginia, to maintain tighter restrictions. He also said he will continue regular discussions with Hogan and Bowser “to be as consistent as we can” in reopening.

Fitzpatrick said Georgia’s experience demonstrates the need for coordinated reopenings among neighboring states, since new outbreaks in one would quickly spill over into others.

“This is a huge concern for the D.C. region,” Fitzpatrick said. “Our three [jurisdictions] are so closely connected.”

Zhang, the transportation researcher, said he believes Virginia would see even more cross-state travel than Georgia if it reopens first.

“People want a haircut or they’re eager to eat out,” he said. “Virginia businesses could be overwhelmed with too many visitors, which then makes it hard to follow physical distancing rules. If we don’t coordinate among the three, this could cause issues.”

Reopening D.C., Maryland and Virginia: What the latest metrics tell us

Fitzpatrick said it will take at least two weeks to see if Georgia’s increase in interstate travel results in higher rates of covid-19 hospitalizations and deaths.

Even so, she said, the kinds of businesses people are probably flocking to — hair salons, eat-in restaurants, movie theaters — require or allow more personal contact among more people. That, in turn, increases the risk of transmission, including in nearby states with tighter restrictions.

Luisa Franzini, chair of the health policy and management department at the University of Maryland School of Public Health, said she also expects to see coronavirus cases grow in the Washington region if one jurisdiction reopens before the others.

“It makes sense because it’s one region,” Franzini said. “People move in and out all the time. … It’s very, very concerning because not only the states that are opening are at higher risk, but the neighboring states are also at higher risk.”

The University of Maryland researchers said they also have devised a new tool designed to help governors and local officials decide when it is safe to reopen their economies.

The “Society and Economy Reopening Assessment” tool developed by epidemiologists, public health experts, economists and travel researchers tracks 16 data points. They include health measures, such as counties’ and states’ covid-19 death rates, testing capacity and infections associated with out-of-state travel. The tool also considers economic factors, such as unemployment rates, the number of people working from home and declines in consumer spending.

“We’re not telling people what to do or when to reopen because that’s a political decision,” Zhang said. “We’re just giving people the data all in one place. … They can know if it’s really safe to reopen.”

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