Tennessee and Kansas studies show masks slow spread of virus

Vanderbilt Hospital graphic: The hospitals were grouped into
four categories: fewer than 25% of patients from Tennessee
counties with mask mandates; 26-50%; 51-75%; over 75%.

As coronavirus cases and covid-19 hospitalizations rise in Kentucky and the nation, a study in Kansas shows that mask mandates reduce new-case numbers, and a Tennessee study shows they prevent hospitalizations.

The Tennessee study, at Vanderbilt University, compared hospitalizations from counties with mask requirements and those without. Tennessee has left mask mandates up to county governments.

The study found that in hospitals where at least 75 percent of patients came from counties that were subject to a local mask requirement, covid-19 hospitalizations were at about the same level in October as they were on July 1.

In hospitals where fewer than 25% of covid-19 patients were subject to a mask mandate, hospitalizations were more than 200% higher than their July 1 levels.

That said, the researchers note that masking is not a "silver bullet," since early October every region of the state has seen a growth in hospitalizations.

"Again, however, this growth has been most dramatic in hospitals that draw a large percentage of patients from areas without mask requirements," says the study report. Further, it says, "This “flattening” of the hospitalization curve is what public health authorities mean when they discuss the role of behavior change and non-pharmaceutical interventions in limiting the impact of covid-19 on the health care sector until new therapeutics and a vaccine are available."

 

University of Kansas chart, with internal labels added by Kentucky Health News

The Kansas study, by the University of Kansas Institute for Policy and Social Research, also found that masks work to slow the spread of the virus, reports The Wichita Eagle.

This study compared the seven-day rolling average of daily cases in counties that did not opt out of the statewide mask mandate with counties that did. Data for the study was collected between March and October.

The researchers found that the counties with a mask mandate saw a decrease in virus cases starting 14 days after the mandate, and their case numbers have remained on a rough plateau. 

The counties that opted out of the mandate have seen a steady increase of cases, and in September, those counties started seeing higher rates compared to the counties with a mask mandate. 

"We found a 50% reduction in the spread of covid-19 in counties that had a mask mandate compared to those without," Donna K. Ginther, director of the institute, said in a video presenting the study's findings.