Study: Masks ‘considerably reduce’ spread of COVID-19 in schools

TUCSON, Ariz. (KOLD News 13) - A study co-authored by Pima County found that universal mask-wearing “considerably reduces the likelihood of a school-associated COVID-19 outbreak.”

The report was released by the CDC on Friday, Sept. 24, one day after the Tucson Unified School District voted to keep its mask mandate despite a state law that goes into effect next week.

Arizona lawmakers passed several bills which prohibit public schools from requiring face masks in early June, but the law does not go into effect until Wednesday, Sept. 29.

Also, a Maricopa County judge is expected to rule soon on a lawsuit that could overturn the law. The coalition of educators, parents and children’s advocacy groups argue that the provisions in the law were unconstitutionally tucked into several unrelated budget bills. They also claim the highly contagious delta variant of COVID-19 makes the need for masks more pressing.

According to Pima County, the study included 999 K–12 public non-charter schools in Pima and Maricopa counties. The study said schools without mask requirements were “3.5 times more likely to experience a COVID-19 outbreak.”

Pima County Health Department director Dr. Theresa Cullen was one of seven authors of the study, which was led by Arizona State University.

“The findings reinforce and give credence to the existing guidance from the CDC and Pima County: Universal mask wearing in schools is absolutely an essential part of a layered mitigation strategy against the spread of COVID-19,” Cullen said.

Of 191 school-associated outbreaks, 8.4 percent occurred in schools that had a mask mandate in place at the start of the school year, 32.5 percent happened in school with requirements that were put in place later while 59.2 percent happened in schools without a requirement.

The CDC on Friday also released the results of two other studies about masks.

One found case rates in children and teens increased more in U.S. counties where public schools had no mask mandates than in those where schools had that requirement. These studies lacked data on other measures that could have influenced the results.

Another study counted 1,801 coronavirus-related school closures through mid-September, most of them in the South, where many schools opened earlier than those in other regions.