COVID-19 hospitalizations in Tennessee have increased by 30% since early June, driven largely by rising case numbers and hospitalizations in the Chattanooga and Memphis regions, according to a new study released Tuesday.

The report from faculty researchers at Vanderbilt University Medical Center and Vanderbilt University School of Medicine found that the number of hospitalized COVID-19 patients reached its highest level to date on Monday, June 15, when more than 400 patients were hospitalized across Tennessee.

The largest increases were in the Memphis Delta region and Southeast Tennessee around Chattanooga, according to the report.

The Tennessee Department of Health reported an additional 40 hospitalized patients on Tuesday, June 16, for a total of 448 patients with COVID-19 hospitalized in the state.

Although the state's health systems have handled the volumes of COVID-19 patients thus far, authors of the report said the noteworthy increase underscores how quickly hospitalizations can swell.

Vanderbilt's projections indicate that if current case trends continue, the state may see days with 1,000 or more COVID-19 hospitalizations at the same time in July or August. That scenario assumes that 95% of cases are mild enough to avoid hospitalization, and that 0.7% of infected cases result in death.

"The rise in hospitalizations is as much about the virus expanding its footprint into additional areas of the state as it is about hospitalizations increasing in facilities that were already treating COVID-19 patients," John Graves, associate professor of health policy and director of the Center for Health Economic Modeling at Vanderbilt, said in a news release.

The report highlights Chattanooga as a region of newly rising case numbers and hospitalizations.

On Tuesday, Rae Bond, chairwoman of the local COVID-19 Task Force, said there were 57 coronavirus patients at the area's hospital systems, which include Memorial, Erlanger and Parkridge in Chattanooga, as well as Tennova in Cleveland, Tennessee, and Hamilton in Dalton, Georgia. She said that total is down from the region's high of 64 patients.

The Hamilton County Health Department on Tuesday reported 44 COVID-19 hospitalizations (including 14 in the intensive care unit or ICU). That's down from a record-high 53 (including 22 in ICU) last week.

The county also added 52 new cases Tuesday for a total of 1,941 cases — 983 active cases, 936 recovered and 22 deaths since the pandemic began.

On Monday, Hamilton County Mayor Jim Coppinger said it's important to remember that the county's hospital data includes patients from outside the region. He also said that the county's hospitals are not currently overwhelmed with COVID-19 patients.

On the other hand, Memphis has seen a steady rise in the number of hospitalized COVID-19 patients, as well as patients requiring intensive care and ventilators. Nashville's hospitalizations have remained below their height in early May, according to the Vanderbilt report.

Researchers attributed these differences to the Memphis population being at higher risk for serious COVID-19 infection, compared to Nashville, which has a younger, more healthy population in general.

Another potential reason for the rise in hospitalizations is that patients from neighboring states come to Tennessee for medical care, which is especially relevant to Memphis and Chattanooga, researchers said.

"While our data do not contain information on home residence of hospitalized COVID- 19 patients, we can use historical hospitalization data to get a sense of how many out-of-state patients may be in Tennessee hospitals. If historical hospital use patterns apply to COVID-19 patients, we estimate that approximately 10-15% of COVID-19 patients currently hospitalized in Tennessee may be from neighboring states," the report states.

Bond said area hospitals are going to start differentiating how many people of the COVID-19 patients hospitalized in Hamilton County are residents from outside counties, but that data is not now available publicly.

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