The senior author of a study of coronavirus spread in schools in one county in Wisconsin corrected Secretary of Education Miguel Cardona after he cited the study to back the use of masking in schools, in comments on Twitter.
“A Wisconsin study found that schools that required masking had a 37% lower incidence of COVID-19 than the surrounding community,” Cardona claimed in a tweet on Monday.
Cardona cited a study on the Centers for Disease Control website that looked at coronavirus transmission in 17 schools in Wood County, Wisc., from August 31 through November 29 in 2020. The study found that just seven students and zero staff members contracted coronavirus from in-school transmission, even while coronavirus positivity rates exceeded 40 percent in all of Wood County during the time of the study.
However, the senior author of the study, Dr. Tracy Beth Høeg, replied to Cardona that the study was not able to say whether mask-wearing affected the low transmission rates observed in the schools.
“Secretary Cardona, I was the senior author of this study. Our study is not able to give any information about the role masks played in the observed low in-school transmission rates,” Høeg wrote. “We had no control group so don’t know if the rate would have been different without masks.”
Secretary Cardona, I was the senior author of this study. Our study is not able to give any information about the role masks played in the observed low in-school transmission rates. We had no control group so don't know if the rate would have been different without masks.
— Tracy Høeg, MD, PhD (@TracyBethHoeg) September 28, 2021
The study notes that self-reported masking compliance within the schools was high and that mitigation techniques including masking may be effective in allowing students to return to class in-person.
“With masking requirements and student cohorting, transmission risk within schools appeared low, suggesting that schools might be able to safely open with appropriate mitigation efforts in place,” the summary of the study states.
The study was released in January 2021, weeks after the U.S. began administering coronavirus vaccines. In March, Høeg and other researchers contended in a USA Today op-ed that the CDC was misinterpreting the Wisconsin study and other data for its school reopening guidance.