Student Well-Being What the Research Says

CDC: COVID Outbreaks Far Higher at Schools Without Mask Mandates

By Sarah D. Sparks — September 24, 2021 3 min read
Two students wearing masks and backpacks in front of lockers.
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In the first month of school alone, more than 1,800 schools nationwide have been forced to close or move to virtual learning because of pandemic outbreaks, new federal data show—but schools that required universal masking were much less likely to see widespread infection.

That’s the upshot of new research on the post-Delta school landscape, released Friday afternoon by the Centers for Disease Control and Prevention. Researchers in two studies analyzed overall child coronavirus infections in 520 counties with different school masking policies, as well as specific outbreaks in schools in the two largest districts in Arizona.

Nearly 250 districts nationwide, as well as 384 additional individual schools, have had to close at least one day because of outbreaks since the 2021-22 school year began in August, one of the studies found. Those closures reduced in-person learning time for more than 933,000 K-12 students. Georgia, Kentucky, Tennessee, and Texas each had more than 250 schools closed due to outbreaks in August, with the closures in Tennessee topping 400. Both Tennessee and Texas bar school districts from requiring face masks, while Georgia and Kentucky allow school districts to decide mask mandates.

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Image of a face mask on school notebook.
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In Pima and Maricopa counties in Arizona, researchers led by Megan Jehn of Arizona State University compared outbreaks in schools that required universal masking indoors from the first day of school to those in schools that implemented mask requirements later or not at all. Of about 1,000 schools in the districts, about 48 percent never required masks; 21 percent required masks from day one; and 31 percent required masks after a few weeks.

The study found schools that required all students and staff on campus to wear face masks—regardless of whether or not they were vaccinated—were 3.5 times less likely to have a coronavirus outbreak by mid-September than schools that didn’t implement masking, after controlling for other factors in the schools.

‘Past time’ to require masks, says schools chief

Arizona Schools Superintendent Kathy Hoffman, who has been fighting against Gov. Doug Ducey’s statewide ban on mask mandates, said the results suggest it is “past time” for schools to be able to require masks.

“It is irresponsible of the state government to stand in the way of local leaders making decisions that protect the health and safety of their students and staff,” Hoffman said in a tweet. “Until we have suppressed community spread by vaccinating more individuals, including children under 12, universal masking will continue to be a critical tool in limiting the spread of the virus in our schools.”

A separate study also found that nationwide, counties where schools did not require face masks had bigger jumps in the rates of children under 18 contracting COVID-19 once school started. Researchers compared child infection rates in July, before school started, to those through Sept. 4. About two weeks after the start of school—the normal range for new COVID-19 infections to show symptoms—the daily pediatric case rates jumped by about 16 per 100,000 for children in counties with school masking, compared to nearly 35 per 100,000 for children in counties without school masking.

The study covered all pediatric COVID-19 cases, not just those among school-age children, and it did not control for the levels of teacher or student vaccination in each school, but researchers pledged a follow-up study to look at these factors.

Though prior studies have also suggested masking, vaccination, and regular COVID-19 testing can reduce the spread of COVID-19 in schools, states and districts have been mired in legal battles for months over whether and when to require teachers and students to wear face masks.

Tobin Novasio, the superintendent for the Lockwood school district in Montana, said he doubts research will sway policymakers in his community.

“The pendulum has kind of swung in our district, and I think the [school] board, they’re hearing so much from the anti-maskers that it’s going to be a difficult call for us to ever go to require masking,” he said. “We are implementing other mitigation strategies, but masking has become such a flashpoint. ... I think that people are so dug into their positions, that it will take personal exposure, personal impact to get people to change where they are at at this point.”

School Mask Mandates at a Glance

  • As of Dec. 1, nine states have banned school districts from setting universal mask mandates. Those bans are in effect in four states. In the remaining five states, mask mandate bans have been blocked, suspended, or are not being enforced. Seventeen states and the District of Columbia require masks be worn in schools.


    1. Florida

    On Sept. 22, Florida's surgeon general instituted a rule that gives parents and legal guardians "sole discretion" over masking in schools. On Nov. 5, a judge sided with the state health department in a legal challenge to rule. On Nov. 18 Gov. DeSantis signed a bill that allows parents to sue school districts that require masks.

    2. Oklahoma

    On Sept. 1, an Oklahoma judge temporarily blocked the state law banning school mask mandates, but students or their parents can still opt out of school mask mandates if they choose.

    3. Utah

    In Utah, local health departments can issue 30-day school mask mandates with approval from the state or county government, according to the state’s top education official.

    4. Texas

    On Dec. 1, an appeals court halted a federal judge’s order that had stopped Texas from enforcing its ban on mask mandates in schools.


    1. Arizona

    On Sept. 27, a judge in Arizona blocked the state laws banning mask mandates that were set to take effect on Sept. 29. On Nov. 2, the Arizona Supreme Court upheld that ruling.

    2. Arkansas

    In Arkansas, a judge paused the state law that prohibits local officials from setting mask mandates, meaning school districts can—at least for now—set their own local mask requirements.

    3. Iowa

    On Sept. 13, a federal judge ordered Iowa to halt enforcement of its law banning mask mandates in schools. The order was later extended.

    4. South Carolina

    On Sept. 28, a federal judge suspended South Carolina from enforcing the rule that banned school districts from requiring masks for students.

    5. Tennessee

    On Nov. 14, a federal judge ordered the temporary suspension of a new Tennessee law that prevented schools from issuing mask mandates.


    1. California
    2. Connecticut
    3. Delaware
    4. District of Columbia
    5. Hawaii
    6. Illinois
    7. Louisiana

    According to a State of Emergency proclamation issued Nov. 23, students are required to wear masks in schools, but districts can opt out of the mandate if they adopt an isolation and quarantine policy consistent with the state's department of health protocols.

    8. Maryland
    9. Massachusetts

    On Oct. 26, Massachusetts extended the mask requirement through Jan. 15. On Sept. 27, Massachusetts said schools can apply for a waiver from the face covering rules if 80% of their students and staff have been vaccinated. If a school reaches the 80% threshold, unvaccinated students and employees are still required to wear masks.

    10. Nevada
    11. New Jersey
    12. New York
    13. New Mexico
    14. Oregon
    15. Pennsylvania
    16. Rhode Island
    17. Virginia
    18. Washington
  • Updated 12/02/2021 | Sources: Local media reports | Learn more here

A version of this article appeared in the October 06, 2021 edition of Education Week as CDC Director Approves Booster Shots For Teachers, Reversing Panel’s Decision


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