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Unmasking the Evidence

Abstract: The use of a face mask as a preventive device for COVID is not supported by real, unbiased science. Because I follow the science in an evidence-based practice, I will not require either patients or staff to wear a mask at the clinic.


I just listened to a press conference Joe Biden, the possible President-Elect. Among other things, he implored all Americans to “wear a mask” as their patriotic duty. “We are all in this together,” he says, so we should all make the sacrifice to wear a mask for the next several months. The mask is, if you listen closely to what he is saying and emphasizing, the centerpiece of his strategy.


The mantra of his political party has been “follow the science. Trust science. Do what the scientists say.” I am a person of faith, but my faith is not in science or scientists, so pardon my skepticism for a moment. The sheer religiosity of the argument I just heard on television gives me pause.


I feel compelled here to interject a comment about the nature of knowledge. Science does not prove anything. Science is a process of inquiry. Scientists make observations, form hypotheses to explain those observations or question them, then design studies to generate data. Based on the data, we accept or reject hypotheses. This means that the conclusions of science may change over time as more information is available. Our understanding of the universe around us evolves this way. Science is part of my everyday existence at work. It is one of the three pillars of evidence-based practice. So what does the science really say about the use of facemasks in the context of the pandemic emanating from communist China?


Debate has been refueled with the study that came out last Wednesday from Denmark, published in the Annals of Internal Medicine. This study looked at infection rates of people who wore masks and those who didn’t. There was no statistically significant difference at all in their infection rates. One immediate conclusion is that the mask makes no difference. Critics who are mask advocates point out that the study did not measure whether the mask protected noninfected people. Nevertheless, if masks could reduce infection rates from a viral agent, then wearing them would make sense. The data do not suggest this at all.


Many of those who advocate “follow the science” like to quote the Center for Disease Control (CDC) as a definitive source. The CDC has already released a study this past fall that concluded that masks do not prevent infection from Covid 19 even among those who wear them consistently. “In the 14 days before illness onset, 71% of case-patients and 74% of control participants reported always using cloth face coverings or other mask types when in public,” the report stated. There is not a chasm of difference between 71% and 74%. Maybe the Danish study is correct.


From Global Research, a publication of the Center for Research on Globalization, we have several studies in synopsis:

So far, most studies found little to no evidence for the effectiveness of cloth face masks in the general population, neither as personal protective equipment nor as a source control.

  1. A May 2020 meta-study on pandemic influenza published by the US CDC found that face masks had no effect, neither as personal protective equipment nor as a source control.

  2. A July 2020 review by the Oxford Centre for Evidence-Based Medicine found that there is no evidence for the effectiveness of cloth masks against virus infection or transmission.

  3. A Covid-19 cross-country study by the University of East Anglia came to the conclusion that a mask requirement was of no benefit and could even increase the risk of infection.

  4. An April 2020 review by two US professors in respiratory and infectious disease from the University of Illinois concluded that face masks have no effect in everyday life, neither as self-protection nor to protect third parties (so-called source control).

  5. An article in the New England Journal of Medicine from May 2020 came to the conclusion that cloth face masks offer little to no protection in everyday life.

  6. A July 2020 study by Japanese researchers found that cloth masks “offer zero protection against coronavirus” due to their large pore size and generally poor fit.

  7. A 2015 study in the British Medical Journal BMJ Open found that cloth masks were penetrated by 97% of particles and may increase infection risk by retaining moisture or repeated use.


The Global Research piece goes on to talk about studies that are supportive of mask use:

Some recent studies argued that cloth face masks are indeed effective against the new coronavirus and could at least prevent the infection of other people. However, most of these studies suffer from poor methodology and sometimes show the opposite of what they claim.

Typically, these studies ignore the effect of other measures, the natural development of infection numbers, changes in test activity, or they compare countries with very different conditions.

An overview:

  1. A German study claimed that the introduction of compulsory masks in German cities had led to a decrease in infections. But the data do not support this: in some cities there was no change, in others a decrease, in others an increase in infections (see graph below). The city of Jena was an ‘exception’ only because it simultaneously introduced the strictest quarantine rules in Germany, but the study did not mention this.

  2. A study in the journal PNAS claimed that masks had led to a decrease in infections in three hotspots (including New York City). This did not take into account the natural decrease in infections and other measures. The study was so flawed that over 40 scientists recommended that the study be withdrawn.

  3. A US study claimed that mandatory masks had led to a decrease in infections in 15 states. The study did not take into account that the incidence of infection was already declining in most states at that time. A comparison with other states was not made.

  4. A Canadian study claimed that countries with mandatory masks had fewer deaths than countries without mandatory masks. But the study compared African, Latin American, Asian and Eastern European countries with very different infection rates and population structures.

  5. A much-cited meta-study in the journal Lancet claimed that masks “could” lead to a reduction in the risk of infection, but the studies considered mainly hospitals (Sars-1), medical (not cloth) masks, and the strength of the evidence was reported as “low”.


A friend recently asked me, “If masks are not effective in preventing disease, why have hospitals use them for so long?” This is not a bad question at all. Hospitals have used them. Particularly in operating rooms and other areas where isolation for infection control is necessary, masks have always been a mainstay. However, this is an apple to orange comparison. The purpose for the mask in this situation is to prevent bacteria from leaving the mouth and contaminating a surface area or open wound. This is vastly different from trying to stop a virus, which is molecular in size. Masks have their place, but don’t think for a minute that they will screen viruses.


Back to my humble clinic for a minute: based on the evidence, I do not see a strong case to be made for wearing a mask to prevent infection from Covid 19. While many businesses are requiring people to wear a mask upon entry, including grocery stores, retail establishments, and even churches, I will not require a mask at the clinic. The evidence before me does not support mandatory masking. Adults will be treated like adults who have full power of choice. Certainly, patients are welcome to mask if they so desire or if it increases a sense of security. But, please know that the lack of a mask in the context of the Iris City Chiropractic Center is not related to a lack of knowledge or concern, but rather is related to the paucity of evidence to compel it.





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