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Rush hour traffic on I-10 West becomes lighter than usual amid the outbreak of coronavirus (COVID-19) in New Orleans, Monday, March 16, 2020.

Baton Rouge and Acadiana will still get hit hard by the community spread of the novel coronavirus, but Louisiana will be spared the most intense infection rates New Orleans experienced in March largely because people are staying home from work, an analysis of the commuter figures indicate.

The most intense hot spots of confirmed cases of the often deadly COVID-19 started in New Orleans then spread along commuter routes into the city’s suburbs. The daily hot spots moved to Jefferson and St. Tammany, then St. John the Baptist and St. Charles parishes, according to a comparison of the Louisiana Department of Health reports and the counts collected by the American Association of State Highway and Transportation Officials, and the U.S. Census Bureau. The program is a planning tool designed to show travel flow between home and work.

The commuter reports also document that far more people, from far more parishes come to work in Baton Rouge than in New Orleans.

The commuter statistics indicate the virus would have blossomed out across the state from Baton Rouge, but for the governor’s “stay at home order” issued after seeing what was happening in the New Orleans metro area, said Dr. Catherine O’Neal, who teaches infectious diseases at the LSU medical school and is chief medical officer at the Our Lady of the Lake Regional Medical Center in Baton Rouge.

“If we had not sheltered in place, if New Orleans had a lower level of positives (that wouldn’t have alerted officials), then the cat would have gotten out of the bag,” O-Neal said. “It’s not like we’re a good spot. … But the ‘stay in place’ slows it down, not just for Baton Rouge but for Bunkie, Eunice and Ville Platte.”

“We’re watching the entire state,” Gov. John Bel Edwards told reporters Friday after noting that the New Orleans area is seeing improvements. “We want to make sure everybody is trending in the right direction. ... Some areas of the state are behind others.”

But the capital area is growing at a “slightly less alarming” rate than New Orleans did.

The coronavirus outbreak was first recognized in December in Wuhan, China. On Jan. 30, the spread of coronavirus was considered an international public health emergency and by March 11 was recognized as a pandemic.

The virus spreads easily, apparently traveling through the air in tiny droplets when an infected person breathes, talks, coughs or sneezes. That’s why all the precautions, such as frequent hand-washing, the “shelter in place” directives and limits to gatherings of more than 10 people were put in place.

Louisiana’s first positive test was March 9 in New Orleans. The spread of the disease grew exponentially causing Edwards to close casinos and suspend schools. Edwards then joined a number of states by ordering everyone but essential workers to stay at home starting March 23. That order has been extended to at least April 30, which will keep thousands of businesses closed.

But for two weeks, 93,086 people commuted into New Orleans for work, nearly all of them from eight parishes and two Mississippi counties, according to the AASHTO/Census Bureau figures. Of that number, 54,438 drove into the city from Jefferson Parish and another 14,221 crossed the Interstate 10 twin span and the Causeway Bridge from St. Tammany for their jobs.

The number of people testing positive for coronavirus infections in Orleans Parish increased to 95 on March 17 and to 827 a week later. New Orleans charted 5,600 cases with 235 deaths on Sunday.

More tests became available during the time period, but at the same time, the color-coded maps used by the federal Centers for Disease Control and Prevention showed blue circles growing ever darker, indicating higher concentrations of confirmed COVID-19 cases, in suburban communities along I-10.

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The numbers in Jefferson Parish showed a jump from 7 on March 14, to 90 on March 20 and 744 positive cases a week later. Jefferson had 4,990 confirmed cases Sunday while St. Tammany, whose numbers also escalated over a similar time-period had 864 cases Sunday.

St. John Parish, just across the Bonnet Carre Spillway from Jefferson Parish saws its numbers start to dramatically increase about four days later on March 24. On Friday, the parish had the highest per-capita death rate in the U.S.

East Baton Rouge Parish went from one case on March 18 to 105 confirmations on March 26. As of Sunday, 25 days after the first discovery, East Baton Rouge had 1,223 cases.

About twice as many drivers as New Orleans commute from 276 locales to work in Baton Rouge. Another 23,009 Baton Rouge residents head out to work in 39 other parishes. Suburban communities, particularly in Ascension Parish are charting high positive tests but not at the same steep rate as the New Orleans suburbs.

About 2,300 drivers go between Baton Rouge and Lafayette, the largest commuter flow between two Louisiana cities, while about 1,500 workers travel between Baton Rouge and New Orleans for work, the second largest.

Commuting statistics are not part of the predictive modeling Louisiana uses.

The governor’s modeling, generally, has been aimed at projecting peaks in the number of cases under various scenarios — what happens if schools and workplaces close, for instance — then comparing those predictions with available hospital beds and equipment.

The administration is using Statistical Analysis System software that begins with health officials’ calculation of how many people a single sick person would infect under different scenarios. The software generally takes various statistics and executes analytic algorithms that can predict various outcomes for official to analyze.

The state also uses R software, which more easily can turn the numbers into graphs.

Edwards said last week that a result of Louisiana’s sheltering in place directive is a decrease in that number mathematically from three to four other people being infected by a single person to below two.

Aly Neel, the health department’s spokeswoman, said commuter information is not incorporated in Louisiana’s models, though officials have noted that the well-respected models created by Johns Hopkins University in Baltimore does include such data. The state is “looking forward to partnering soon” with Johns Hopkins, she said.

“While we do not collect or track spread by commuters specifically, the Department (of Health) and the governor have said repeatedly we believe COVID-19 to be in every parish of this state. It's because we are concerned about spread that the governor put in place and then extended the ‘stay at home’ order,” Neel said.


Email Mark Ballard at mballard@theadvocate.com.