Vanderbilt report: Models suggest Tennessee could reach 1K active COVID-19 hospitalizations in July

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Posted at 1:34 PM, Jun 16, 2020
and last updated 2020-06-16 14:34:12-04

NASHVILLE, Tenn. (WTVF) — This week, Tennessee reported its highest level of active hospitalizations for COVID-19 with 400 patients across the state being treated.

In their most recent report, researchers at Vanderbilt University Medical Center say the current hospitalization rate has not put acute stress on the state's health care system, but that does not guarantee that another increase in hospitalizations will occur in areas with the capacity to treat them.

In its recent projections, researchers believe Tennessee could reach 1,000 concurrent hospitalizations for COVID-19 later this summer.

In Tennessee, the current rate of transmission for the virus is at 1.13 statewide. If the transmission rate remains, the state would hit 1,000 concurrent hospitalizations in late July or early August.

If the rate increases, it could be reached earlier in mid-July. Researchers said only if the transmission rate decreases to 1 or below would the state avoid 1,000 concurrent hospitalizations this year.

Vanderbilt's projections also looked at two scenarios. Scenario A assumes there is a large proportion, between 85 and 90%, of cases that go undetected and an implied lower likelihood of death and hospitalization among infected cases. Scenario B looks at a situation researchers say is more in line with the current scientific consensus by assuming 95% of cases are mild enough to avoid hospitalization and a 0.7% death rate.

The increase in these hospitalizations is occurring particularly in two regions: the Memphis Delta and Southeastern Tennessee, which includes Chattanooga.

Overall, Middle Tennessee has had the largest number of hospitalizations to date, but hospitalizations in this region have been more stable over the last two weeks. The report said Nashville saw its highest levels of hospitalization for COVID-19 in early May.

The current number of active hospitalizations for COVID-19 is an increase of 30% from the week prior. Researchers said the increase in hospitalizations has been more gradual than the increases in cases.

During the first week of June, Tennessee had an average of 570 people testing positive each day, which is 50% higher than the average during the first week of May.

Researchers named two reasons the hospitalization rate has not risen proportionately with case numbers over the course of the pandemic.

One being the risk profile of positive cases has varied over time and across regions.

Vanderbilt researchers are now using a COVID-19 Case Mix Index to track daily infections. This index adjusts case totals to track the hospitalization risk of new positive cases each day and gives insight into the risk of hospitalizations growing based on the degree of vulnerability of the population that has been diagnosed.

The second could be the use of Tennessee hospitals by residents of neighboring states, particularly in hospitals near Memphis and Chattanooga.

Vanderbilt used historical hospitalization data to get an idea of how many out-of-state patients may be treated for COVID-19 in Tennessee hospitals. Researchers estimate about 10 to 15% of COVID-19 patients that are currently being hospitalized in the state are from neighboring states.

"The recent rise in hospitalizations is not a simple story, and is a story with multiple parts,” said Dr. John Graves, associate professor of Health Policy and director of the Center for Health Economic Modeling at Vanderbilt. "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."

The report notes that as hospitals return to elective procedures and as testing capacity increases, many inpatients are tested for COVID-19 regardless of their reason for hospitalization. This can result in "incidental" hospitalized COVID-19 cases numbers among those who test positive but have not been admitted for complications related to the virus.

"We believe this number is small, but the data available do not allow us to distinguish these patients from those hospitalized because of their COVID infection," the report says.

You can read the most recent report by clicking here.