There are MAJOR FLAWS with the Duke study that concluded kids under 12 should wear masks in schools

The New York Times published an op-ed by Dr. Kanecia Zimmerman, an associate professor of pediatrics at the Duke University School of Medicine and Dr. Danny Benjamin Jr., a pediatric-infectious-disease specialist at Duke Health that concluded “one of the most one of the most effective and efficient strategies for preventing SARS-CoV-2 transmission in schools”:

For kids under 12 who cannot be vaccinated, universal masking is “one of the most effective and efficient strategies for preventing SARS-CoV-2 transmission in schools.”https://t.co/6BWn7Ku1Qy

— Apoorva Mandavilli (@apoorva_nyc) August 11, 2021

The researchers found only 363 cases out of 40,000 exposed in schools and believe “the low rate of transmission occurred because of [universal masking”:

https://twitter.com/linseymarr/status/1425246801699946506

But there are some major flaws with their analysis. . .

“The evidence here that unmasked kids spread COVID more than masked kids in school seems to be a handful of anecdotes, some from foreign countries, and others from summer camps”:

The evidence here that unmasked kids spread COVID more than masked kids in school seems to be a handful of anecdotes, some from foreign countries, and others from summer camps. https://t.co/wwoXmSqO1W

— Tim Carney (@TPCarney) August 10, 2021

And they admit they “could not compare masked schools to unmasked schools”:

"Because North Carolina had a mask mandate for all K-12 schools, we could not compare masked schools to unmasked schools."

Headline:https://t.co/tEaotOl8Sz

— Corey A. DeAngelis (@DeAngelisCorey) August 10, 2021

In other words, there is NO CONTROL GROUP in this study:

Must-read thread. Authors of a study that supported masking in schools had no control group. https://t.co/Msir11zp6p

— Robby Soave (@robbysoave) August 10, 2021

A topline finding of the Duke/ABC Science Collaborative report, and what they claim here, is that masks in schools help lower transmission. Except all their schools were under a mask mandate. I asked the authors how they could make a claim on masks when there was no control …

— David Zweig (@davidzweig) August 10, 2021

In order to claim an effect you must compare one group with an intervention to a different group *without* the intervention, which they didn't do. Instead, the authors replied with the Israeli study, saying that showed masks in schools work. Except…

— David Zweig (@davidzweig) August 10, 2021

1)You cannot use another study as evidence for a claimed finding in your study
2)The Israel study was of grades 7-12; windows were closed; and all schools were exempt from masks. If anything, the fact that there was only one outbreak suggests the lack of effectiveness of masks

— David Zweig (@davidzweig) August 10, 2021

pic.twitter.com/vwt5QLqPbf

— David Zweig (@davidzweig) August 10, 2021

The authors do the same thing in this Opinion piece, citing some districts that had mask mandates and low transmission as evidence of their effectiveness, and cherry picking some places that didn't to suggest the opposite…

— David Zweig (@davidzweig) August 10, 2021

Yet schools in Florida, and more so throughout many parts of Europe did not and do not have mask mandates for kids, with varying age cutoffs, and there is no correlated explosion of cases originated in those schools

— David Zweig (@davidzweig) August 10, 2021

Sadly, they buried the lede from their report, which is that distancing of more than 3 feet or less than 3 feet made no difference in transmission rates

— David Zweig (@davidzweig) August 10, 2021