Missouri GOP Gov. denies hiding study proving mask effectiveness against COVID

The study showed that the masked regions had lower rates of infection compared to unmasked regions. While regions with mask mandates reported an average of 15.8 newly confirmed COVID-19 cases per day for every 100,000 residents, regions without mask mandates reported an average of 21.7 cases per day for every 100,000 residents.

In a November 3, 2021 email forwarded to Parson's office, state health Director Donald Kauerauf wrote that the study showed that masked regions reported "a lower positivity rate per 100,000 and experienced lower death rates."