Controversy on COVID-19 mask study spotlights messiness of science during a pandemic

Women wearing face masks in a park
Women wearing face masks in a park

risingthermals / Flickr cc

Late last week, a group of researchers posted a letter that they had sent to the Proceedings of National Academy of Sciences (PNAS) requesting the retraction of a study published the week before that purportedly showed mask use was the most effective intervention in slowing the spread of COVID-19 in New York City.

Though PNAS editors have yet to respond to the request, scientists have roundly criticized the study's methodology, and the entire kerfuffle has highlighted the difficulty of "doing science" amid a full-blown pandemic.

The paper in question, "Identifying airborne transmission as the dominant route for the spread of COVID-19" states, "After April 3, the only difference in the regulatory measures between NYC and the United States lies in face covering on April 17 in NYC."

The group of scientists, many from Stanford and Johns Hopkins universities, took umbrage with that conclusion and said it is verifiably false on several accounts: Other parts of the country had mandated mask use, and different parts of the United States had different degrees of "lockdown."

"While masks are almost certainly an effective public health measure for preventing and slowing the spread of SARS-CoV-2, the claims presented in this study are dangerously misleading and lack any basis in evidence," they wrote in a letter to the PNAS editorial board, requesting retraction. "Unfortunately, since its publication on June 11th, this article has been distributed and shared widely in traditional and social media, where its claims are being interpreted as rigorous science."

'Stakes are much higher than before'

Noah Haber, ScD, a postdoctoral fellow at Stanford University, said he has heard from PNAS editors that they have received the letter. Haber was the first co-signer of the letter requesting retraction.

"The policy implications of this paper is immediate, so we hope response is commensurate with the decisions that need to be made," he told CIDRAP News.

Haber said he and his colleagues are not arguing the usefulness of masks, but instead pointing out that the study in question could not evaluate how effective masking policies are relative to other policies.

"There are an enormous number of severe errors with the paper," Haber said. "Unfortunately, this is not a new problem in science, but the stakes are much higher than before."

Haber said the paper also highlights the problems of doing science in the midst of a pandemic caused by a novel virus: An enormous, unprecedented volume of studies have been published on COVID-19. But unfortunately, many don't hold up and are methodologically flawed.

"Under normal circumstances, years-long debate would filter wheat from the chaff, but everything is happening so immediately now," he said. 

No time for science to self-correct

David Kriebel, ScD, a professor of epidemiology at the University of Massachusetts-Lowell, has followed the controversy. While he agrees that the PNAS study is flawed, he does not agree with a retraction at this time. The paper wasn't a failure of the peer review process, he said, but rather a failure of understanding the limits of science during a pandemic.

"The kind of science we are talking about—and the public has become so remarkably informed about—is applied science being used to inform decision-making on a mass scale," Kriebel said. "That kind of science is really quite different in important ways from the work of geologists, chemists, or astronomers. It has an urgency; it has to be translated to millions of people, and quickly."

Kriebel said that usually science is self-correcting, given enough time. But currently there is not enough time for science to self-correct when it's being used to craft public health policy. He said that's a problem for policy makers over-relying on "capital S" science to justify decisions.

"It's actually not helpful for scientists to hide behind a curtain of certainty. There is uncertainty about masks. But that doesn't mean we shouldn't be wearing them," Kriebel said. Instead of clamoring for scientific studies to back up mandates on mask use, Kriebel argues for more transparency in public health messaging.

"I would say, 'Mask use is our best judgment right now, and we will tell you if we get more evidence," he said.

Both Kriebel and Haber agree that masks probably do offer a level of protection, but right now there is no way to tease out how much protection masks offer versus physical distancing of 6 feet or more, or hand washing.

"The world is much messier than we would like to admit," said Kreibel. "We do our best and admit our uncertainty."

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