A Deceptive Covid Study, Unmasked

Duke researchers look at transmission in schools and end up reinforcing their prior assumptions

By Jay Bhattacharya and Tom Nicholson. Excerpts:

"‘Follow the science,” we keep hearing, but sometimes scientists and the media present findings in a misleading way. Consider a new study by Duke University’s ABC Science Collaborative, conducted in partnership with the North Carolina Department of Health and Human Services. Researchers examined the effect of a “test to stay” approach to schoolchildren identified as “close contacts” of Covid-positive people. Test to stay excuses these children from quarantining if they test negative for the virus. The study’s primary conclusion was that test to stay is a good way to move away from lengthy quarantine.

That’s reasonable and useful. But the researchers peppered their report with rhetorical sleights of hand aimed at misleading readers into other, less well-founded conclusions that were mostly inevitable products of their own study design. One of their primary conclusions is that “in schools with universal masking, test-to-stay is an effective strategy.” That invites readers to assume that test-to-stay doesn’t work without forced masking. But since they studied no unmasked schools, this conclusion is baseless. An honest report would either have said so or not mentioned masking at all."

"True, the ABC researchers found a higher rate of transmission during sports. But that was entirely a product of how the researchers defined Covid “exposure.” Students were counted as exposed only if they were unmasked during the interaction with an infected person. In mask-mandatory schools, that happened only during lunch and sports. If a transmission occurred in a masked classroom, the definition didn’t count it as a close contact. And the study found only three sports-related positives out of 352 tests. When combined with the three lunch-related positives, the six total positives resulted in a mere 1.7% of maskless exposures ending up with a Covid-19-positive contact."