Missouri health department found mask mandates work, but didn’t make findings public
By Rudi Keller, Derek Kravitz and Smarth Gupta | Missouri Independent
Published December 1, 2021 at 3:38 PM CST
Missouri Governor's Office
Donald Kauerauf, the director of the Department of Health and Senior Services, speaks during a press conference at the Missouri Capitol in July.
Mask mandates saved lives and prevented COVID-19 infections in Missouri’s biggest cities during the worst part of the delta variant wave, an analysis by the state Department of Health and Senior Services shows.
But the analysis, conducted at the request of Gov. Mike Parson’s office in early November, was never made public and was only obtained by The Missouri Independent and the Documenting COVID-19 project after a Sunshine Law request to the department.
The study compared infection and death rates in St. Louis, St. Louis County, Kansas City and Jackson County with the rest of the state. New state health Director Donald Kauerauf wrote in an email that the study’s findings showed the effectiveness of mask mandates and forwarded it to Parson’s office.
The analysis wasn’t included in material the department prepared for cabinet meetings, the emails show. Neither the health department nor Parson’s office responded to requests for comment asking why the data has not been shared publicly.
The comparison showed infection rates in “masked” jurisdictions were higher than the rest of the state in the six weeks prior to the emergence of the delta variant. Case rates then fell below other regions as the surge gathered force in late May and have remained lower since that time.
The statewide data shows that, from the end of April to the end of October, jurisdictions with mask mandates experienced an average of 15.8 cases per day for every 100,000 residents compared to 21.7 cases per day for every 100,000 residents in unmasked communities.
The four jurisdictions imposed their mask mandates in late July and early August, as the delta variant wave was peaking.
Mask requirements remain in place in St. Louis and St. Louis County. The Jackson County Legislature voted to end its requirement in early November, and the mandate in Kansas City ended Nov. 5 except for schools and school buses.
There are a number of variables that impact infection and death rates, the health director wrote in a Nov. 3 email. But the effectiveness of masks is clear, he wrote.
"I think we can say with great confidence reviewing the public health literature and then looking at the results in your study that communities where masks were required had a lower positivity rate per 100,000 and experienced lower death rates,” Kauerauf wrote.
Mask mandates have been one of the hottest political issues of the year, pitting the authority of local officials against political opposition to masks led by Republican state officials.
Parson has spoken out repeatedly against local mask mandates, calling them "WRONG" in a tweet and a contributor to the erosion of public trust. Attorney General Eric Schmitt has gone a step further, suing St. Louis, St. Louis County, Kansas City and Jackson County to block enforcement of their mask mandates.
“Jackson County has imposed an unlawful, arbitrary, and capricious mask mandate that is not supported by the data or the science,” the opening sentence to Schmitt’s lawsuit against Jackson County states.
Schmitt has also sued Columbia Public Schools for instituting mask mandates.
The state’s analysis backs up St. Louis’ push to keep its mask mandate, said Nick Dunne, spokesman for St. Louis Mayor Tishaura Jones.
“More than anything it confirms for us what our public health experts have been saying, that masks are an effective tool for reducing community transmission,” Dunne said.
By Rudi Keller, Derek Kravitz and Smarth Gupta | Missouri Independent
Published December 1, 2021 at 3:38 PM CST

Missouri Governor's Office
Donald Kauerauf, the director of the Department of Health and Senior Services, speaks during a press conference at the Missouri Capitol in July.
Mask mandates saved lives and prevented COVID-19 infections in Missouri’s biggest cities during the worst part of the delta variant wave, an analysis by the state Department of Health and Senior Services shows.
But the analysis, conducted at the request of Gov. Mike Parson’s office in early November, was never made public and was only obtained by The Missouri Independent and the Documenting COVID-19 project after a Sunshine Law request to the department.
The study compared infection and death rates in St. Louis, St. Louis County, Kansas City and Jackson County with the rest of the state. New state health Director Donald Kauerauf wrote in an email that the study’s findings showed the effectiveness of mask mandates and forwarded it to Parson’s office.
The analysis wasn’t included in material the department prepared for cabinet meetings, the emails show. Neither the health department nor Parson’s office responded to requests for comment asking why the data has not been shared publicly.
The comparison showed infection rates in “masked” jurisdictions were higher than the rest of the state in the six weeks prior to the emergence of the delta variant. Case rates then fell below other regions as the surge gathered force in late May and have remained lower since that time.
The statewide data shows that, from the end of April to the end of October, jurisdictions with mask mandates experienced an average of 15.8 cases per day for every 100,000 residents compared to 21.7 cases per day for every 100,000 residents in unmasked communities.
The four jurisdictions imposed their mask mandates in late July and early August, as the delta variant wave was peaking.

Mask requirements remain in place in St. Louis and St. Louis County. The Jackson County Legislature voted to end its requirement in early November, and the mandate in Kansas City ended Nov. 5 except for schools and school buses.
There are a number of variables that impact infection and death rates, the health director wrote in a Nov. 3 email. But the effectiveness of masks is clear, he wrote.
"I think we can say with great confidence reviewing the public health literature and then looking at the results in your study that communities where masks were required had a lower positivity rate per 100,000 and experienced lower death rates,” Kauerauf wrote.
Mask mandates have been one of the hottest political issues of the year, pitting the authority of local officials against political opposition to masks led by Republican state officials.
Parson has spoken out repeatedly against local mask mandates, calling them "WRONG" in a tweet and a contributor to the erosion of public trust. Attorney General Eric Schmitt has gone a step further, suing St. Louis, St. Louis County, Kansas City and Jackson County to block enforcement of their mask mandates.
“Jackson County has imposed an unlawful, arbitrary, and capricious mask mandate that is not supported by the data or the science,” the opening sentence to Schmitt’s lawsuit against Jackson County states.
Schmitt has also sued Columbia Public Schools for instituting mask mandates.
The state’s analysis backs up St. Louis’ push to keep its mask mandate, said Nick Dunne, spokesman for St. Louis Mayor Tishaura Jones.
“More than anything it confirms for us what our public health experts have been saying, that masks are an effective tool for reducing community transmission,” Dunne said.