If Tennesseans abandon the social distancing efforts that succeeded at slowing the spread of the coronavirus, more than one out of every 10 state residents could be infected and 50,000 people may be hospitalized in May, Vanderbilt researchers said Friday.

These predictions come from an unlikely scenario where social distancing is reversed despite the advocacy of public health experts and local and state leaders. But the research illustrates the harrowing potential for the virus to spread if residents ignore instructions to minimize exposure.

Even a few people could inflame the outbreak, like embers igniting a wildfire, researchers said. And Tennessee has so much to lose.

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“Our model says the over 4,000 cases we have in the state of Tennessee right now could have been sparked by as a few as 10 patients six weeks ago," Melinda Buntin, a Vanderbilt health policy professor, said Friday. "So it doesn't take many of those 4,000 cases out there going to Easter Sunday services and the like to spark a huge resurgence in cases across the state of Tennessee."

These predictions come from highly anticipated coronavirus modeling by the Vanderbilt University Department of Health Policy, which studied the virus in an effort to forecast the spread in the coming weeks and months. The modeling is largely based on transmission rates, which is a measurement of far each person spreads the virus.

As of mid-March, every Tennessean with the virus was believed to infect five others, researchers said. Social distancing has since reduced this rate to about 1.4. To fully suppress the outbreak, this rate must drop below 1 and stay there.

Based on the fluctuation of this transmission rate, researchers have forecast three scenarios for the outbreak:

Status quo scenario: In this scenario, Tennessee keeps current social distancing strategies in place and the transmission rate of the virus remains where it is today. It is predicted the virus would peak in June with about 5,000 hospitalizations, which would stretch but not shatter the capacity of hospitals.

In this scenario, Tennessee keeps current social distancing strategies in place and the transmission rate of the virus remains where it is today. It is predicted the virus would peak in June with about 5,000 hospitalizations, which would stretch but not shatter the capacity of hospitals. The optimistic scenario: Improvements to social distancing lowers the transmission rate below 1, which means the virus peaks in mid-May with only 2,000 to 3,000 hospitalizations. Hospitals should be more than capable to handle the patient load.

Improvements to social distancing lowers the transmission rate below 1, which means the virus peaks in mid-May with only 2,000 to 3,000 hospitalizations. Hospitals should be more than capable to handle the patient load. The reversal scenario: If Tennessee were to abandon social distancing now, the transmission rate of the virus may rise back to where it began. Each infected person would infect as many as five others, and as much as 13% of the population would be infected. By mid-May, 50,000 people would be hospitalized.

Lack of testing, underreported deaths

None of the scenarios presented on Friday estimate how many Tennesseans will die.

Vanderbilt officials said fatalities are particularly difficult to predict, at least in part because the current deaths are likely underreported due to limits on the availability of coronavirus testing.

John Graves, a Vanderbilt professor at the core of the modeling effort, said Thursday a lack of testing hampered efforts to forecast the virus also.

“Our model has to assume that only a fraction of people who are infected have been tested,” Graves said. “And we’ve seen some delays and stalls in testing over the last month or so. So, I think, we are definitely not at the place right now where we have the widespread testing necessary to relax social distancing.”

Gov. Bill Lee and state officials often tout Tennessee as a nationwide leader on coronavirus testing. Tennessee has the 16th highest rate of testing in the U.S. — second in the south behind Louisiana — according to data from The COVID Tracking Project.

Lee said Thursday he was not aware of any testing facility turning away people who had been recommended for a coronavirus by a medical professional.

"We are trying to get ourselves in a position where folks are not turned away and, in fact, developing strategies to ramp up testing significantly all across the state,” Lee said. "We have a strong commitment to it.”

As of Friday afternoon, nearly 63,000 residents have been tested for the virus, detecting 4,862 positive cases according to the Tennessee Department of Health.

At least 98 people have died.

Confusion on coronavirus projections

The governor has said this Vanderbilt modeling will be a guide as his administration works to combat the outbreak in the coming weeks and months. However, on Thursday, a key member of Lee’s cabinet appeared to misinterpret the modeling.

When asked about some predictions in the model — a peak in June and 5,000 hospitalizations — Health Commissioner Lisa Piercey dismissed this scenario as unlikely.

“It is our understanding, and this is subject to change based on further conversation, but it’s our understanding that the model that projects a big surge in June is contingent upon complete reversal of the current social distancing practices,” Piercey said. “I don’t believe anybody expects that to happen.”

Piercey was wrong. In actuality, the Vanderbilt model predicts a June peak and 5,000 hospitalizations if Tennessee continues on its current course, which Vanderbilt describes as a "status quo" scenario.

Gillum Ferguson, a spokesman for the governor, said Friday the Lee administration had “multiple follow-up conversations” with Vanderbilt to clarify some aspects of the Vanderbilt modeling.

“We're looking at a number of models, not just Vanderbilt's, but ultimately, a model is just that – one of many tools in our toolbox — so excessive weighting of statements in the model itself or by individuals should be avoided,” Ferguson said.

Brett Kelman is the health care reporter for The Tennessean. He can be reached at 615-259-8287 or at brett.kelman@tennessean.com. Follow him on Twitter at @brettkelman.