Study Showing Masks Aren't Harmful May Do More Harm Than Good

John Mandrola, MD


November 03, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's  Coronavirus Resource Center.

I got into trouble (again) on Twitter. My tweet concerned a research letter published in the Journal of the American Medical Association on the safety of wearing a nonmedical mask.

For this study, 25 people recruited from a retirement condominium self-recorded their oxygen saturations before, during, and after wearing a three-layer disposable mask.

There were no differences. The pooled mean sats were about 96%. The authors concluded that wearing a mask was not harmful.

I described this as a howler "study" that worsens our science trust problem and demeans an important journal.

I then made an unforced error in the reply thread by saying, "Does literally anybody think a mask is hazardous?"

Numerous people scolded me for being either too dumb or too arrogant not to have realized that many people say masks are hazardous.

While I regret suggesting that no one thinks masks are hazardous, I stand by my original take that publishing dubious COVID-19 papers is counterproductive. It persuades no one, demeans the mission of medical journals, and is potentially harmful to the progress of science.

Below is my thinking.

First, the Lack of Persuasion

Of course, I know that there are people who don't want to wear a mask and that some of them cite health hazards. But any rational person understands that masks are not dangerous. A mask is dehumanizing and uncomfortable—it may create a sense of increased work when breathing during heavy exertion—but a mask is not hazardous.

Irrational people will not be convinced by a research letter—in any journal.

A person who holds an irrational mask concern who is shown this study could say, "What about the CO2?" Then you'd have to do another study with blood gases. If that was negative, an irrational person could say a mask causes arrhythmias. Then you'd have to do a study with ECG monitors. Irrational people can make any claim about masks. The quest to disprove them is foolish.

Since the authors of the paper, and the editors of JAMA are physicians, they well know that people who hold irrational beliefs are not persuaded by a study of 25 participants.

My friend Saurabh Jha, MD, summed up the mask issue well in a tweet: "Rationale for masks isn't empiricism but the  precautionary principle. What's worrying is that people can't seem to act solely on the precautionary principle." Weak studies, Jha holds, only intensify the mask debate.

Loss of Trust in Science

In the internet age, if you are going to make an empirical argument, it had better be airtight. This study is far from that. Anyone with medical knowledge, or access to the internet, knows that oxygen saturation is a lousy surrogate of pulmonary well-being. I've seen people nearly die because of CO2 retention—with oxygen saturations in the normal range.

The authors knew there would be no difference in oxygen saturations from a single nonmedical mask, but they still did the study. The editors knew the study proved nothing, but they still published it. In one day, the paper had more than 13,000 page views and an Altmetric score of 536. This paper will be cited often.

The business model of medical journals is attention—page views, citations, and media coverage. That a top-tier medical journal publishes the equivalent of a high-school science project tempts me to believe that attention trumps scientific merit.

Think about the next time JAMA publishes a really important finding—say, a study on vaccines. People turned cynical by the publishing of flawed attention-grabbing studies could reasonably think the journal editors are not fair judges of good science. When the important paper comes, scientists will now have to say, yes, yes, we know medical journals publish flawed studies for attention, but this really important paper is different.

In addition to attention, the findings of this study will surely be held up as a cudgel to persuade people to wear masks, the enforcement of which is a policy issue. When medical journals take sides in political debates, they lose the perception of impartiality.

That is a problem because dealing with a pandemic requires people to cooperate. This requires trust. And trust is hard-won but easily lost.

Reducing True Scientific Progress

Academic cardiologist Venk Murthy, MD, highlighted the opportunity costs of this study: "The issue isn't whether it was clickbait or not but whether the researchers, IRB, reviewers, editors, etc could have spent their time more productively than [on] something so obviously true."

The incentive structure for scientists is also attention—publications and citations. When scientists see papers like this garner attention, it's natural for them to do similar studies, however dubious.

Scientists, who are also supposed to be impartial, can easily perceive the policy positions of a journal's editors. Thus, not only are researchers incentivized to do dubious studies, they are also incentivized to discover findings consistent with the prevailing narrative.

Murthy's take is that worthy research in virology, public health, cancer, heart disease, and other areas has been put on hold by the race to garner attention with COVID studies.

Restoring Faith in Masks and Science

Medical leaders must embrace uncertainty, and medical journals should steer clear of any perception of dualities of interest. Impartiality is a must. Journal editors must not be perceived as favoring certain findings.

As for masks, if we want people to wear masks, and we do, the answer is not to promote flawed science. It is to use the tools of any good doctor: humility, empathy, and common sense.

The humility to tell people we don't know—exactly—how much masks slow the spread of the virus.  

The empathy to say that we know that masks take away a lot of what makes us human.

The common sense to say that masks are not dangerous, and, because mask-wearing probably helps reduce viral spread, and it isn't forever, please, wear a mask—especially in confined indoor spaces.

John Mandrola practices cardiac electrophysiology in Louisville, Kentucky, and is a writer and podcaster for Medscape. He espouses a conservative approach to medical practice. He participates in clinical research and writes often about the state of medical evidence. 

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