Coronavirus hospitalizations are stable or declining in areas of Tennessee such as Hamilton County - where face masks are mandated in public - and growing in areas without such requirements, according to a report from Vanderbilt University released Monday.
Using historical hospital data on patient ZIP codes and daily COVID-19 hospitalization data, researchers from Vanderbilt's School of Medicine and University Medical Center grouped hospitals by the percentage of patients they typically treat from areas with and without face mask requirements.
Hospitals that primarily treated patients from areas without mask requirements on average saw a more than 200% increase in hospitalized COVID-19 patients since July 1, while hospitals that treat more patients from areas of the state with face mask requirements have seen their number of coronavirus patients stabilize or decline.
"There is a lot of variation in both how the pandemic has played out and the masking requirements across Tennessee, and we wanted to know if there's any association between those requirements and COVID-19 hospitalizations," said John Graves, associate professor of health policy and director of the Center for Health Economic Modeling at Vanderbilt.
"We can't say for sure that masking is the reason this is happening, because there are often other interventions in places like Nashville and Memphis where bars and restaurants are limited, but we do see a clear relationship between areas where masks are required and hospitalizations for the coronavirus," Graves said.
Tennessee Gov. Bill Lee has taken heat from physician groups and other advocacy organizations over his decision not to implement a statewide face mask requirement, saying that he doesn't believe in a one-size-fits-all mandate. Instead, he said that decision is best left up to mayors in individual counties.
As of Monday, 26 of Tennessee's 95 counties - containing roughly 68% of the state's population - were subject to masking requirements of some kind, according to the report.
Nearly 100% of the population in the "Highland Rim" region around Nashville and Davidson County and the Mid-South region around Memphis are under a mask requirement, while in other regions of the state, less than 25% of the population is under a mask requirement, according to the report.
COVID-19 hospitalizations, along with new cases and deaths, are one of the key metrics that officials monitor to gauge the severity of the COVID-19 pandemic. Concern remains that if health systems become overwhelmed with patients, they may have to scale back other services, activate overflow plans or compromise the quality of care. Many hospitals, including the ones in Hamilton County, treat patients from larger areas, meaning they're affected by decisions and outbreaks in surrounding counties as well.
Melissa McPheeters, a research professor in the Department of Health Policy who helped author the latest report, said in an email that although parts of Tennessee have seen a "flattening of the curve" when it comes to new cases and hospitalizations over the past couple weeks, the state is by no means out of the woods.
"My concern is that we will react too quickly to that positive news and let up too soon. We need to stay the course with the measures that are just starting to make a difference," McPheeters said. "Certain areas are continuing to see dramatic growth, particularly in our rural counties. We need to keep an eye on those numbers and make sure that all of our counties have the resources they need to stop COVID from spreading."
On Monday, the Hamilton County Health Department reported 82 new cases, bringing the county's number of active cases to 1,398 and cumulative total since the pandemic began to 6,191.
The department reported 75 people hospitalized and 26 people in the intensive care unit with the virus on Monday, both numbers lower than last week. Thirty-three of those patients are Hamilton County residents, and the remaining 49 patients are from outside counties.
Another COVID-19 death was announced Monday, the second reported in two days. Both deaths were white males, one between 51 and 60 years old and the other between 71 and 80 years old. The deaths bring the county total to 55 deaths since the pandemic began and seven so far this month.
"Death is a lagging indicator after hospitalizations, which lags cases. If we use masks to reduce cases, that will in turn lead to reductions in hospitalizations and ultimately deaths," McPheeters said. "It does take some time to turn the ship, but ultimately over a number of weeks, reducing cases through public health interventions like wearing a mask and watching your distance will result in fewer hospitalizations and in fewer deaths."
Last week was the deadliest in the state for COVID-19 since the pandemic began. The virus killed 148 Tennesseans between Aug. 2 and Aug. 8.
Contact Elizabeth Fite at firstname.lastname@example.org.
Staff writer Wyatt Massey contributed to this story.