Mask effectiveness study from Denmark counter to CDC recommendation

Those calling on President Trump and others to listen to the scientists on the coronavirus may not necessarily mean all the science, as the release of a highly anticipated Danish trial on the efficacy of masks suggests.

Debate is raging over the randomized study published Wednesday in the Annals of Internal Medicine that found that coronavirus infection rates were nearly the same among those who were told to wear masks and those who were not.

At the same time, researchers did not examine whether the masks protected others from catching the virus, and stressed that the findings should not be construed as concluding that mask-wearing recommendations are ineffective in reducing the spread of COVID-19.

“Our trial of more than 6,000 participants here in Denmark found similar rates of SARS-CoV-2 infection in those who did and those who did not receive a recommendation to wear a surgical face mask when outside the home,” said Henning Bundgaard, the study’s lead author and University of Copenhagen, in a video.

He cautioned that “our study does not address the effectiveness of widespread mask use for preventing the spread of infection from those infected with SARS-CoV-2.”

Such warnings did little to squelch the enthusiasm of the critics of economic lockdowns, school closures and mask mandates — in other words, those frequently derided as “anti-science” — who trumpeted the findings in a “take-that” moment.

“What we should take away is that masks are basically useless as a protective measure,” said Alex Berenson, author of “Unreported Truths About COVID-19 and Lockdowns,” and a leader of the so-called Covid contrarian camp.

“There’s just no evidence that masks protect the wearer,” Mr. Berenson said on Fox News’ “The Ingraham Angle.” “Now, we can discuss this other issue of source control, we can discuss ’my mask protects you’ — there’s not very good evidence for that, but that’s much harder to test in a big randomized trial.”

The results also flew in the face of the Centers for Disease Control and Prevention, which said for the first time in a scientific bulletin posted Nov. 10 that wearing masks may protect the wearers as well as those with whom they come into contact.

“Studies demonstrate that cloth mask materials can also reduce wearers’ exposure to infectious droplets through filtration, including filtration of fine droplets and particles less than 10 microns,” said the CDC bulletin.

Fun fact: the Danish mask study probably OVERESTIMATES the real-world efficacy of masks because people were given 50 free and pretty high-quality masks to use - and instructed in their use.

— Alex Berenson (@AlexBerenson) November 18, 2020

 

Mr. Berenson said that “the CDC said last week masks may protect the wearer, and they should just stop saying that. There’s no evidence for that.”

Sen. Rand Paul, Kentucky Republican, cited the study Thursday as he took aim at recently enacted shutdown orders in his state and Michigan.

“The edicts that are coming from the governor and from the governor of Michigan — they’re completely arbitrary,” Mr. Paul, a physician by trade, said on Fox Business. “They’re not based in any kind of science. There’s really very little objective science to prove that any of this works. In fact, the Danish study on mask shows that objectively, guess what, the cloth masks don’t work, they’re theater.”

Rep. Andy Biggs, Arizona Republican, greeted the study’s appearance by tweeting: “THIS JUST IN. Masks don’t do what the ’experts’ have been telling you that they do.”

Worst fears

Fears that the study would be used to boost facial-covering opponents may have been why it took until November for the study to appear. According to the Danish newspaper Berlingske, at least three major journals declined to publish the research.

Not everyone was happy to see the study featured in a prominent scientific publication.

“Some have turned to social media to ask why a trial that may diminish enthusiasm for masks and may be misinterpreted was published in a top medical journal,” said Dr. Vijay Prasad on MedPage Today. “Woah! First, of all, I am prepared to die on the hill that science means publishing the results of truthful experiments no matter what they show.”

Christine Laine, editor-in-chief of Annals of Internal Medicine, defended the decision to publish the trial.

“The Annals of Internal Medicine published this carefully designed randomized trial because it informs our understanding of the role of masks in mitigating the pandemic,” Ms. Laine said in a video. “It would be irresponsible to squelch the findings because they did not show what we hoped to see as advocates of mask wearing.”

Some major media outlets ignored the story, while others that covered it were quick to stress that masks should still be viewed as de rigueur.

The New York Times emphasized that the findings were “not likely to alter public health recommendations in the United States” in an article headlined, “A New Study Questions Whether Masks Protect Wearers. You Need to Wear Them Anyway.”

The Associated Press mentioned the story in an “explainer,” saying that the research had “a number of flaws,” including participant compliance.

In the trial conducted in April and May, when mask use was uncommon in Denmark, half the participants were told to wear masks outside their homes, and were provided with surgical masks, while the other half were told not to cover their faces.

“During the study period, authorities did not recommend face mask use outside hospital settings and mask use was rare in community settings,” said the study. “This means that study participants’ exposure was overwhelmingly to persons not wearing masks.”

After a month, 1.8% of those who were told to wear masks had tested positive for COVID-19 while 2.1% of those in the control group had developed the infection.

The trial was conducted early on in the pandemic, when detected cases of the virus were not as widespread, and not everyone who was told to wear a mask always did so. Of course, neither do some Americans, even in states and cities with mask-wearing orders.

“Among participants, 46% wore the mask as recommended and 47% wore it “predominantly as recommended,” for a total of 93%,” said Dr. Prasad. “Anyone who has walked around any city or store in America can attest: that is actually pretty good! To my eye, one in four noses are seen protruding, and one in eight masks are worn as a chin strap.”

Ms. Laine concluded that the findings “do not mean that mask wearing during the pandemic is ineffective.”

“Rather, this trial shows that people wearing masks among others who are not wearing masks remain vulnerable to infection,” she said. “Other studies suggest lower spread of infection in settings where most people wear masks. What we know from those studies plus the current trial should motivate widespread mask wearing to protect everyone.”