I question the conclusions drawn in the letter to the editor in last week’s paper Un-masking the truth. The primary reference upon which this letter is based is the recent review from the Cochrane Library titled Physical interventions to interrupt or reduce the spread of respiratory viruses, January 30, 2023. Based on this review from the Cochrane Library, the author of last week’s letter concludes “the science shows masking does not reduce infection.” As pointed out in the Editor’s Note in the parallel column, the reader must be aware of what was actually evaluated in this Cochrane report. This report is a review of the effectiveness of mask mandates, not a review of the effectiveness of mask wearing. In an updated comment on this Cochrane Library report (April 26, 2023) the authors of the Cochrane report state “This review did not directly assess the impact of wearing a mask but compared the outcome in populations assigned to an intervention aimed at increased mask wearing compared with not being assigned to this intervention group.” The correct conclusion based on this Cochrane report is that protocols that seek to promote mask wearing (mask mandates) have not proven to be effective in reducing respiratory infection rates. Or simply, mask mandates have not worked.
The next logical question is why have mask mandates been ineffective? I can suggest two possibilities: 1) the mask mandates weren’t followed, or 2) masks don’t work. Let’s consider the first option. The authors of the Cochrane report state: “The high risk of bias in the trials, variation in outcome measurement, and relatively low adherence with the interventions during the studies hampers drawing firm conclusions.” And “Adherence with interventions [eg. masks] was low in many studies.” This is an admission that masks were not worn as directed, ie. the mask mandates were not followed. For example, in one of the studies upon which this Cochrane report is based (Alfelali 2020), only 24.7% of participants in the intervention group used masks daily, while 14.3% participants in the control group used masks. And of the mask users, the majority reported using the mask for less than 1 hour per day. So the answer to the question “Do mask mandates work?” is predictable – if the people in the study didn’t wear masks, then the study won’t find any benefit from mask wearing. But that doesn’t mean that masks don’t work, it only means that you can’t find any benefits from mask wearing among people who don’t wear masks. And it has not been demonstrated that mask mandates are ineffective when compliance with mask wearing is high.
Now back to the second option – do masks work? When I again researched this question as I have done a number of times over the past three years, I was surprised by the number of articles now available on the subject and my impression is that the weight of evidence showing benefits from mask wearing is growing (and yes, I am well aware this is a hotly debated subject, and there are many who vehemently disagree with me – that’s one of the benefits of living in a free society – we don’t have to agree. You can believe and act as you choose, and I can do the same. And each of us will enjoy or suffer the consequences of our choices). Do a Google search for “masks effectiveness evidence” (or something similar) and disregard the “sponsored” hits (assuming they are likely to be biased). Perhaps the most pointed article I have seen is one published in the Journal of Travel Medicine, October 2021, Unmasking the mask studies: why the effectiveness of surgical masks in preventing respiratory infections has been underestimated, which concludes: “When interpreted in light of these considerations, the evidence indicates that, in addition to preventing the wearer from spreading respiratory infections, masks also protect the wearer from contracting them. The studies that did not find statistically significant effects prove only that masks cannot offer protection if they are not worn.”
As a person who has been wearing a mask for 30+ years while working in a health care setting (for many years a surgical mask, for the past couple of years an N95 mask) I have a hard time understanding why so many people object to wearing a mask. Masks do take some getting used to, but once you adjust to the mask I find it easier to wear a mask than to wear glasses. Yet millions of people wear glasses, whether corrective lenses, sunglasses, or for eye protection, with little complaint. Wearing a mask is a simple thing individuals can do to help protect themselves. Finding a comfortable and well-fitting mask can take some effort – I’ll admit I’ve worn some pretty uncomfortable masks. Another study, Effectiveness of Face Mask or Respirator Use in Indoor Public Settings for Prevention of SARS-CoV-2 Infection ” California, February-December 2021, from the CDC, reports “consistently wearing a face mask or respirator in indoor public settings reduces the risk of acquiring SARS-CoV-2 infection,” with higher levels of protection associated with better masks (cloth < surgical < N95) and more consistent wear (never < some of the time < most of the time). The above study reports up to an 83% reduction in the odds ratio of a positive Covid test among the “N95” group (and one would assume these were also in the “most of the time” group) relative to those who did noy wear a mask. Masks are not a silver bullet – they can’t confer 100% protection, but they can significantly reduce your risk of spreading or contracting a respiratory infection when a well-fitting mask is worn consistently.
Jeff Corbett
McBride, BC
