Research shows Tennessee counties without mask mandates have higher COVID-19 death rates

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Posted at 10:55 AM, Nov 10, 2020
and last updated 2020-11-10 11:55:35-05

NASHVILLE, Tenn. (WTVF) — New research from Vanderbilt University Medical Center shows counties in Tennessee that do not have mask mandates have a significantly higher death rate of COVID-19 cases.

Researchers compared areas of the state that did not have mask requirements over the summer and found those with mask requirements had "substantially lower death rates due to COVID-19" in comparison. As of the first week of October, areas that never implemented a mask requirement saw more than four deaths per 100,000 residents. Whereas areas that implemented a mandate over the summer saw two deaths per 100,000 residents.

Counties that adopted a mandate early saw the death rate begin to decline in July. Counties that adopted one later saw a decline in August and September. Areas that still continue to not require masks have seen death rates rise.

The analysis showed death rates were at first higher in areas where masks became required, but after weeks of a mandate in place, there was a sharp decline in deaths per 100,000 population in comparison to areas without a mandate.

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This graph shows the trends in deaths per week in Tennessee, based on the date of death and the county in which the deceased lived. This analysis expands on VUMC's earlier analyses of the impact of masking policies by dividing counties into groups depending on the timing of mask policy implementation. Specifically, counties are categorized based on whether they were an early adopter (i.e., mask mandate in place as of July 10, the cutoff date used in our previous reports; these counties are shown in GRAY), a later adopter (i.e., mask mandate in place after July 10; shown in BLACK), or a never adopter (shown in RED).

Researchers noted the data they looked at reflects the actual date of death, which lags in reporting by several weeks. Due to the lag, Tennessee's report of COVID-19 deaths only represents deaths through the first week of October.

"Deaths are a lagging indicator, following increases in cases and then hospitalizations, so we expect any intervention such as a mask requirement to take some time to demonstrate effectiveness. Rising rates of COVID-19 are a big ship to turn, and it is important to act early enough to be effective," explained Dr. Melissa McPheeters, a research professor of Health Policy and Biomedical Informatics.

As of November 10, about 63% of Tennesseans live in areas where a mask is required when in public, 37% live in an area where masks have never been required and 8% live in areas where a mask mandate has since expired.

"This analysis shows that strategies, including but not limited to masking while in contact with others, can have real impact on people’s lives," said Dr. John Graves, director of Vanderbilt's Center for Heath Economic Modeling. "Mask mandates are associated with greater mask wearing and other behaviors like limiting close contacts with others, and the combined impact is clear and substantial."

As active cases rise in Tennessee and around the country, researchers are pointing to small gatherings as potential spreading events. According to a study by Carnegie Mellon University, 80% of Tennesseans reported that they are wearing masks. However, mask-wearing can be inconsistent when around personal contacts or family members.

"Individuals may not understand the risk of exposure to friends and family and may ‘let down their guard’ in situations where they are meeting in small groups with close contacts," the researchers said. "Mask ordinances demonstrate leadership by sending a clear signal that behavior must change to mitigate spread of the virus."

Restrictions on group gatherings, business capacity and operations were lifted after September 30 in 89 counties, where about 60% of Tennesseans live.

Active cases and hospitalizations have been surging in the state for nearly a month. Tennessee has topped its records for single-day new cases, active hospitalizations and single-day reports of deaths frequently since early October. As of November 9, 3,610 people have died from COVID-19 in Tennessee.