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.