Three studies released in Friday's CDC Morbidity and Mortality Weekly Report, including one focused on Maricopa and Pima counties, underscore the value of COVID-19 prevention strategies like universal masking in keeping schools open.
The studies show school districts and counties without mask mandates were significantly more likely to see COVID-19 outbreaks.
In Maricopa and Pima counties, K-2 schools were 3.5 times more prone to outbreaks than schools that required masks from the start of the academic year.
In a statement, state Superintendent of Public Instruction Kathy Hoffman said the report reflects what "public health experts have been telling our governor for months," and called the state government "irresponsible" for standing in the way of local leaders' safety decisions.
In addition to masking up, the CDC recommends screening tests and vaccinations for all eligible parties.