According to data released Friday by the Centers for Disease Control and Prevention, schools in Arizona that did not require masks for students and staff were nearly four times more likely to experience a COVID-19 outbreak than those that did.
According to the data, just under 60% of Maricopa and Pima County schools that reported outbreaks after in-person classes resumed in late July did not have mask requirements for students and staff.
Of the 999 kindergarten through 12th-grade public schools included in the analysis, 191 reported outbreaks of the virus, which were defined as two or more confirmed cases among students or staff within a 14-day period and at least seven days after in-person learning started, the agency said.
Among the schools with outbreaks, 113 did not have masking requirements and 20 implemented face covering policies within roughly two weeks or more of classes resuming, it said.
Sixteen of the outbreaks occurred in schools that enacted mask requirements before or soon after reopening, the data showed.
“CDC recommends universal indoor masking in K-12 schools,” the agency researchers wrote. “However, masking requirements in K-12 schools vary by school district, county and state.”
Maricopa and Pima counties, which encompass the Phoenix metropolitan area, account for more than 75% of Arizona’s population, according to U.S. census figures.
At the time of the analysis, 48% of Maricopa County residents and 59% of Pima County residents had received at least one dose of a COVID-19 vaccine, the CDC reported.
The analysis did not include data on the number of COVID-19 cases among students and staff reported in school outbreaks.
However, a separate report, also released by agency Friday. found twice as many cases among students in counties without school mask requirements nationally than in those with them in place.
About 96% public and private schools in the United States opened for full in-person learning this fall, according to the CDC.
Still, between Aug. 2 and Sept. 17, there were 248 public school district-wide closures and 384 individual school closures — lasting one day or more — linked with COVID-19 outbreaks across the country, the agency said.
The closures affected more than 1,800 schools — or just under 2% of those nationally — nearly 934,000 students and nearly 60,000 teachers in 44 states, with the “number of closures … highest in the South.” it said.
Only people age 12 years and older are eligible to receive the COVID-19 vaccines, although Pfizer-BioNTech announced Monday that the two-dose shot was shown to be safe and effective in clincial trials in children as young as 5 years old.
The similar vaccine from Moderna, as well as the one-dose Johnson & Johnson shot, still are being evaluated in children.
“To prevent COVID-19 outbreaks in schools, CDC recommends multicomponent prevention strategies, including vaccination, universal indoor masking, screening testing and physical distancing,” agency researchers wrote in one of the reports released Friday.