Restaurants, gyms and hotels have the highest risk of COVID-19, study finds

Reopening restaurants poses the greatest risk of the spread of COVID-19, according to a recent study that followed nearly 100 million Americans through their cell phones.

Researchers at Stanford University and Northwestern University used anonymity phone data to map the movements of people in 10 of the largest metropolitan areas in the United States as they left their own neighborhoods for more than 500,000 different destinations, including restaurants and places of worship, from March 1 to May 2. They then overlaid the data on a model of how the virus spreads to determine the infection patterns.

“If you think of restaurants, people stay there for a long time, and many of them are small places where people are crowded,” said Jure Leskovec, lead author of the study, published Tuesday in the journal Nature. “The population density there is quite high compared to the grocery stores and department stores which are larger places and are nowhere near as crowded as the restaurants.”

The chances of getting infected are also higher in gyms, cafes, hotels and places of worship, but the risks are about four times lower than in restaurants, according to the study.

As cases of COVID-19 increase across the country, cities are instituting new restrictions. In New York, Governor Andrew Cuomo, Wednesday imposed a 10 p.m. curfew on restaurants, bars and gyms. The measures were imposed after new infections were frequently attributed to visits to these types of sites, Cuomo said.

In Chicago, just 10% of so-called points of interest – very compact out-of-home sites ranging from full-service restaurants to car dealerships – account for more than 80% of COVID-19 infections, the researchers found. Without limiting where people walk or implementing other containment measures, a third of the U.S. population would be infected with COVID-19 in a single month, according to the results.

“This means that the virus spreads very quickly, and social distancing and staying at home are effective measures to prevent the spread of the virus,” Leskovec said.

According to the study, capping occupancy rates has proven to be an effective reopening strategy. Yes Chicago restaurants, for example, were to reopen at 20% of its capacity, compared to full occupancy, coronavirus infections would be reduced by more than 80%, according to Leskovec. These dining establishments, meanwhile, would only see a 42% reduction in the total number of visits.

Indeed, the relationship between predicted infections and the number of visits is not linear. “One can achieve a disproportionate reduction in infections with a small reduction in visits,” the authors wrote.

“What we are showing very well is that early openings are not all or nothing. Reduced occupancy reopening can be a very effective way to reduce the number of infections,” Leskovec said.

Low-income populations are more prone to infections, the study also showed. This is partly because they could be less able to work from home, or have their groceries delivered, forcing them to come into more frequent contact with people who may be infected with COVID-19.

“In wealthier neighborhoods, people can stay at home,” Leskovec said. “But people in poor neighborhoods have to go to work, or maybe they can’t afford to deliver food.”