Schools without mask mandates in Michigan saw 62% more coronavirus spread

Michigan students who attended K-12 schools with mask requirements in August and September had lower rates of coronavirus transmission than those at schools without mandates, new data from the University of Michigan and the state health department shows.

“There’s a ton of studies out there and we can see it with our own data here in Michigan: Masking helps prevent transmission,” said Marisa Eisenberg, an associate professor in U-M’s departments of epidemiology and complex systems.

Eisenberg led a team at the university comparing case rates among children in school districts with no mask requirements to those with rules in place.

The rate of infection reached an average of about 45 cases per 100,000 students by late September in school districts with mask mandates.

Virus spread was 62% higher in school districts with no mask rules, where the infection rate averaged 73 cases per 100,000 by late September.