Study: Mask mandates cut virus’ spread in St. Louis

November 18, 2020 GMT

ST. LOUIS (AP) — Mask mandates in St. Louis and St. Louis County slowed the spread of the coronavirus this summer when compared to neighboring counties that didn’t require face masks, a Saint Louis University study found.

The study compared infections in St. Louis and St. Louis County beginning in July, when leaders in those communities began requiring masks, to neighboring Franklin, St. Charles and Jefferson counties, the St. Louis Post-Dispatch reported Wednesday.


The study found average daily case growth was 44% less in St. Louis and St. Louis County compared to the neighboring counties three weeks after the metropolitan areas required masks. Twelve weeks after St. Louis-area mask mandates took effect, the average daily case growth was still 40% lower in those areas than in the other suburbs.

The study’s lead author, professor Enbal Shacham, told the newspaper that the study has been submitted to an academic journal for publication and is being peer-reviewed.

A co-author of the study, St. Louis Metropolitan Pandemic Task Force chief Dr. Alex Garza, pushed Missouri Gov. Mike Parson to require face masks throughout the state, despite the Republican’s repeated refusal to do so.

Parson has stressed personal responsibility as key to reducing the virus’ spread. He regularly encourages the use of face masks, social distancing and regular handwashing, though he often posts photos of himself mask-less around other people.

“We are past the time when individual behavior alone can address this disaster,” Garza said during a news briefing Friday. “The spread of cases are blanketing the state and no locale is safe anymore.”

The Saint Louis University study also found that mask mandates in the metropolitan areas reduced disparities in the virus’ impact on higher-risk communities by decreasing the spread in densely populated areas and among people of color.

Residents in middle- and high-income areas stayed home to limit their risk of infection, the study’s authors theorized. Mask mandates particularly helped protect people of color and city residents who were more likely to work essential jobs in grocery stores, health care and public transportation, and therefore couldn’t work from home.


The study’s release comes as COVID-19 cases are surging in Missouri. The state health department as of Wednesday reported more than 30,000 new cases in the past week, or roughly 4,293 per day on average. Close to a quarter of those tested for COVID-19 in the past week were positive.

As of Sunday, 2,453 people with COVID-19 were hospitalized.

A dozen people at the Jackson County jail tested positive and 90 inmates have been quarantined, Kansas City’s KMBC-TV reported.

Twenty residents have died from the virus at a Lee’s Summit nursing home, the Kansas City Star reported. The Jackson County Health Department says John Knox Village Care Center is the site of the largest outbreak in eastern Jackson County, with 157 cases.