The Danish Mask Study

This is the fuller post.   The headline result–wearing a mask makes no difference in cases or in level of transmission in the community.   It is obvious to all of us now, that this is true, as we can see the case growth in areas of the country with extremely high mask-wearing rates.  Here is the cite.  (Danish Mask Study)  Coupled with the withdrawal of the county study which purported to show a benefit based on limited time period study, this should put an end to any Governor claiming that mask mandates are backed by science and data, but it won’t.  As I noted in my flash report, people are already coming out with all kinds of BS criticisms of the trial. It is amusing in a sense, that people who just accepted all the mask modeling “research” without any quibbles or skepticism are finding all kinds of criticism directed at an actual randomized trial attempting to answer a real-life question–what is the effect of wearing a mask in the community.

Before describing the study and its findings, let me make a couple of preliminary observations.  I have been reading medical research for 40 years and science papers for even longer.  When you read this study and you know the history of the attempt to get it published, you are immediately struck by what the authors must have been forced to do to get any reputable journal to publish it.  They were clearly forced to constantly refer to limitations and caveats about the study and there is a discussion about the confidence intervals around the results that you absolutely never see in the published reports of research.  What kind of science is it that decides in advance what the results have to be and tries to suppress any research that challenges those pre-ordained results?  When I complain that science has become completely politicized, what happened to this study is Exhibit A.

Unlike all the garbage modeling studies about mask mandates and mask wearing reducing cases, this was an actual randomized trial on the critical question–does wearing a mask in the community affect the level of transmission, the number of cases, in that community.  It is real-life, we aren’t wearing masks in a model simulation or in some experimental room.  We wear them in the community, in real life, properly, improperly, touching them, not touching them, with gaps, without gaps, changing them frequently or not, washing them or not.  That is the reality of mask-wearing.  That is what this study replicated.

6000 people participated in the study.  3030 were randomly assigned to the mask group and 2994 to the control arm.  Out of the entire group 4862 completed the study period.  These were adults who spent more than 3 hours a day outside their homes and didn’t wear masks at an occupation.  Both the mask wearing arm and the non-mask wearing arm were told to follow social distancing measures.  The mask-wearing group was encouraged to wear a mask outside their home and were given 50 surgical masks for this purpose.  So better masks than cloth ones.  The primary outcome was number of infections after one-month.    42 people got infected in the mask wearing group and 53 in the control group.  Because more dropouts occurred in the mask group, there was no statistical difference in infection rate.  One interesting little nugget in the characteristics of the groups is that more people in the control arm had what might be considered higher-risk occupations than in the mask wearing arm.  Yet still no difference in infection rate.

Some of the criticisms are that the data on mask usage were self-reported, this only tested the effect on the mask wearer, not whether they might be less likely to infect others, and other niggling concerns.  The real criticism is that it doesn’t fall in line with the orthodoxy on all of us needing a mask glued to our face 24 by 7.  Self-reported adherence was good, with over 90% of the mask-wearers saying they largely complied with the recommendation and almost half saying they always did.  Taking out the 7% who reported poor adherence did not change the primary finding.  And very importantly, looking only at those persons who reported always complying with the mask recommendation also did not change the outcome.  It appeared there was very low in-home transmission that caused the infection in either arm of the study, so most transmission was occurring in the community.  Another interesting finding was no difference in infection with other respiratory viruses.

This was a well-designed study. If masks made a difference in the community, it would have been seen in this large a group. And that distinction between protecting the wearer versus others makes no logical sense. Think about it. If wearing a mask doesn’t do a better job of keeping you from getting infected, i.e. keeping the virus from coming in, why would it do a better job of keeping it from going out? In fact, you might expect the opposite, there is less pressure in the inhale than the exhale.

And if the problem is that people who are infected aren’t wearing a mask then wouldn’t we expect to see even higher levels of community spread among the non-mask wearing population–if masks worked, at least on a relative basis the masked people would be better protected from infection than the unmasked ones.  Think about it logically for a minute, if lots of people aren’t wearing masks, and they weren’t at this time in Denmark, according to mask theory there is a tremendous risk of exposure in public.  So there should be an even greater protective effect of a mask protecting the wearer from getting infected, because there is more opportunity for exposure to the virus.  But according to this study, a mask did no better job of protecting the wearer in this hazardous environment than did not wearing a mask.  If anything, this aspect of the trial strengthens the finding.

So wear them if you want to or have to, but don’t for one second think they are offering you or others any significant degree of protection.  And that is my concern about the mask mandate fetish, not only are people being lied to about the science, but they are being misled into thinking they will have a level of protection they won’t.