A scientist’s response to “Not-a-Doctor: Do Masks Work? MEGA-ANALYSIS of Anti-Masker Resources” — fact checking the fact checkers.
Author’s note: Citizen fact-checkers often provide a useful service to their audience by devoting their time to looking into controversial or highly technical issues so their audience doesn’t have to. COVID-19 has created a situation where people are more interested in following scientific advances than ever. As a scientist I am excited to see non-scientists putting in the work to read primary sources and understand the methodology of science studies in an effort to understand and convey current scientific information to their audiences. I think this is something everyone could benefit from doing and the inaccessibility of scientific literature to lay audiences is a major problem stemming both from a lack of general science education and a failure on the part of the academic establishment to make their work accessible and understandable to regular citizens. I am a supporter of open science initiatives and I think it’s always preferable for non-scientists to get involved in science learning by reading and trying to understand scientific sources themselves rather than relying solely on popular science journalism, which tends to be highly sensationalized and often misrepresents or exaggerates the research it is quoting.
As such it is not my intent to discourage ‘lay readers’ from accessing and commenting on primary scientific sources themselves. Scientists and the general public both benefit when non-academic readers go to the source and interpret scientific findings for themselves without the filter of pop-science journalism. As our society becomes more reliant on STEM, a scientifically literate public allows important conversations to move into the mainstream, and discussing issues that affect all of us is the right of every citizen, regardless of their educational background. As such nothing in the following “fact check” is meant to disparage the efforts of non-scientists to interpret and discuss scientific literature. I do not believe only experts can or should weigh in on these issues.
I am not uniquely qualified to comment on these issues myself as I am not a virologist, immunologist, epidemiologist or aerosol physicist. My research is not related to COVID-19 and I am not an expert on any of the topics discussed below. However, I am a working scientist with a BSc in Biology from a research institution, where I received a basic education in immunology and virology. I hold a Masters degree in a STEM field (in the area of life sciences) and am currently a PhD candidate in the same. In the interest of anonymity I won’t be any more specific. While this does not qualify me as an expert on COVID-19 I do feel qualified to comment on the scientific method and biological sciences generally, which is what motivated me to write this “fact check of a fact check.”
In the interest of full disclosure, the video I am “fact checking” — “Not-a-Doctor: Do Masks Work? MEGA-ANALYSIS of Anti-Masker Resources”, was brought to my attention by a mutual friend who was asked for his input prior to the video being scripted. When asked for info/resources by “anti-maskers” he contributed some information I had previously posted on the topic, much of which was sadly not included in the final video. Upon watching the video I was disappointed that many of the resources I contributed were not mentioned, and many of the points I made were not considered. I feel this “citizen fact check” fails because it has not addressed the strongest points “anti-maskers” make and as such I wanted to fact check the fact check. Below is my original response to the author of the video, modified for clarity and to remove identifying details.
Link to the original video: https://www.youtube.com/watch?v=BeXAQdqns9A
Fact checking “Not-a-Doctor: Do Masks Work? MEGA-ANALYSIS of Anti-Masker Resources”
I'd like to give a scientist's perspective on your "fact checking" and your charge that people like me who don't believe there is evidence for efficacy of universal masking are "being manipulated" - a rather loaded claim.
The main issues I have with the video overall can be boiled down to the fact that it employs a number of rhetorical devices that have nothing to do with facts, expertise or science. It is also rife with logical inconsistencies. In particular, your video appears to me to utilize a bizarre combination of 1. egregiously strawmanning your real opponents' views, 2. cherrypicking studies/evidence, in an openly hypocritical manner (hopefully unintentional), and 3. lying by omission, both about the available evidence and about the claims made by so-called "anti-maskers."
I'll try to address the various points in your video one by one in a chronological fashion, though I may reorder certain arguments for the sake of clarity.
I'll start out by saying that I am not claiming there is any incontrovertible proof masks don't work - the evidence is weak one way or another. So I may not be an "anti masker" in the strictest sense as I'm not denying some possibility that under certain circumstances masks might prevent viral transmission to some degree. I'm also not "anti mask" in the sense that I don't want to prevent anybody from wearing masks if they want to. I am anti mask mandates - I don't think that governments should have the right to use coercion to impose face coverings on citizens, especially on such a weak evidentiary basis. That being said I'll try to address your main arguments in turn:
1. Masks as source control
First of all, you start by saying that you think masks work primarily as source control. However you drop this topic early on and nothing you mention later in the video makes any extended reference to this concept. This is understandable since to my knowledge there are exactly zero solid studies investigating masks as source control. That being said, "masks work best as source control" is a spurious claim based solely on a hypothetical.
2. Meta-studies
Second, you bring up the idea of a meta-analysis and call your own video a "mega analysis." That is obviously not a scientific term but you appear to be implying your video functions somewhat as a meta-analysis. This is misleading. Normally, in science, a meta-analysis will involve a systematic literature search using predetermined inclusion and exclusion criteria for studies and instead of commenting on the p-values of those respective studies (i.e. "statistical significance") it will weight each study based on sample size (and occasionally other factors), try to pull out covariates and use the raw data from all included studies to find something like an OR/HR (hazard ratio), i.e. an "effect size" for the pooled data. This is important because effect size is not a comment on statistical significance itself (i.e. the chance that a result would be arrived at purely by randomness alone) but rather the actual magnitude of the observed effect. Hence, you will often find meta-analyses reporting that multiple studies found a “moderate” effect of, e.g., a certain drug in reducing a disease symptom, or, e.g., a 30% reduction in mortality.
While statistical significance is used as a proxy for how likely it is an effect is due to a true difference between two groups, or how likely it is to be completely random, you can find a highly statistically significant effect which is so small as to be functionally insignificant — say, a 0.1% reduction in mortality. Averaging over multiple studies won’t speak to statistical significance but it will give a better picture of the size of the effect any given intervention has, on average over various studies which may use slightly different methods or sample populations. Keep this difference in mind when assessing primary experimental research (like the studies discussed in the video) and meta-analyses or systematic reviews which combine evidence from multiple studies (while meta-analyses always mathematically pool data, systematic reviews may not and may simply summarize studies instead).
Many meta-analyses have been published on mask wearing since the beginning of 2020, most rushed and sloppy, but some of higher quality have been conducted both prior to COVID and throughout the pandemic.
One such study which I linked you to earlier is the below:
https://www.frontiersin.org/articles/10.3389/fmed.2020.564280/full
Here are the main findings:
"Results: A total of 23,892 participants between 7 and 89 years old involved across 15 studies from 11 countries were involved. Key settings identified were Hajj, schools, and in-flight settings. A modest but non-significant protective effect of SM on ARI incidence was observed (pooled OR 0.96, 95% CI 0.8–1.15). Subgroup analysis according to age group, outcome ascertainment and different non-healthcare settings also revealed no significant associations between SM use and ARI incidence.
Conclusion: Surgical mask wearing among individuals in non-healthcare settings is not significantly associated with reduction in ARI incidence in this meta-review."
To interpret that for you further, based on these 15 included studies and the confidence interval of the OR their results are compatible with either a small decreased risk (about 20%) or a small increased risk (15%) of illness due to mask wearing.
This is not inspiring.
This is not to say no studies reported any protective effect but peer-reviewed literature since the pandemic began leans toward no efficacy of masks. Pre-COVID, it’s hard to find any meta-analyses of mask efficacy versus a control, but many find no significant difference between properly fitted n95s and surgical masks — and if masks work as you claim they work in your video, there should be a significant difference. As you yourself point out later on, the filtration efficacy of n95s is provably much higher than that of surgical masks, and n95s should be sealed on the sides, preventing leakage.
Here are some more examples of meta-analyses from before COVID:
“The use of N95 respirators compared with surgical masks is not associated with a lower risk of laboratory‐confirmed influenza. It suggests that N95 respirators should not be recommended for general public and nonhigh‐risk medical staff those are not in close contact with influenza patients or suspected patients.”
(Source: https://onlinelibrary.wiley.com/doi/full/10.1111/jebm.12381)
“ In the meta-analysis of the clinical studies, we found no significant difference between N95 respirators and surgical masks in associated risk of (a) laboratory-confirmed respiratory infection (RCTs: odds ratio [OR] 0.89, 95% confidence interval [CI] 0.64–1.24; cohort study: OR 0.43, 95% CI 0.03–6.41; case–control studies: OR 0.91, 95% CI 0.25–3.36); (b) influenza-like illness (RCTs: OR 0.51, 95% CI 0.19–1.41); or ( c ) reported workplace absenteeism (RCT: OR 0.92, 95% CI 0.57–1.50). In the surrogate exposure studies, N95 respirators were associated with less filter penetration, less face-seal leakage and less total inward leakage under laboratory experimental conditions, compared with surgical masks.”
(Source: https://www.cmaj.ca/content/188/8/567.short)
Conversely, I found one study from before 2020 reporting some advantage of masks overall, though it appears predominantly to apply to bacterial, not viral infections:
“Compared to masks, N95 respirators conferred superior protection against CRI (RR = 0.47; 95% CI: 0.36–0.62) and laboratory-confirmed bacterial (RR = 0.46; 95% CI: 0.34–0.62), but not viral infections or ILI. Meta-analysis of observational studies provided evidence of a protective effect of masks (OR = 0.13; 95% CI: 0.03–0.62) and respirators (OR = 0.12; 95% CI: 0.06–0.26) against severe acute respiratory syndrome (SARS). This systematic review and meta-analysis supports the use of respiratory protection. However, the existing evidence is sparse and findings are inconsistent within and across studies.”
(Source: https://academic.oup.com/cid/article/65/11/1934/4068747)
Suffice it to say that the evidence from meta-studies was not strong pre-pandemic nor does it appear to be strong currently.
3. Evidence-based medicine
You go on to say, and I quote, “unequivocally, 100%, [the studies] all show that masks work.” There is no other way to characterize this statement than as a blatant mischaracterization of the existing data. As you can see from the above meta-analyses, even those that reported a positive effect of masks equivocate quite a lot, and refer to “inconsistent” and “sparse” evidence across the literature.
You might argue that many of these studies were published pre-COVID and that there is better data now. This is partially true as there has been one major study published in 2020 on masks (I will get into this later), but by and large untrue. In fact the evidence remains quite weak and inconsistent, the positive evidence extremely equivocal.
To drive this point home, let’s discuss systematic reviews. In the science community there are a few quite famous centers/groups for evidence based medicine whose sole purpose it is to assess evidence quality for various medical interventions. I should think this would be the first place any non-scientist fact checker would go to find “facts” about the quality of evidence for medical interventions.
[Aside: I did link you to one such assessment prior to the making of your video, but you called the article “problematic” for unstated reasons and characterized it as an “opinion piece.” This is an understandable mistake to make, as rapid systematic reviews may read like an op-ed or commentary to a lay reader. They are not primary research, and in some instances (as with the first article below) are not always formally peer-reviewed. However, systematic reviews, meta-analyses and other types of evidence synthesis are typically regarded as the highest quality evidence, above randomized controlled trials (RCTs), in science and particularly in evidence-based medicine. You mistakenly refer to RCTs as the gold standard of scientific evidence in your video, but systematic reviews which usually assess multiple RCTs, are a step above.]
(Source: https://ncu.libguides.com/researchprocess/systematicreviews)
All of them, with no exceptions, are quite clear that the evidence for mask efficacy both in the COVID-19 context and the influenza/ILI context is weak and inconsistent. I’ll quote some relevant passages and also link the articles.
The Oxford Center for Evidence Based Medicine:
“In 2010, at the end of the last influenza pandemic, there were six published randomised controlled trials with 4,147 participants focusing on the benefits of different types of masks. Two were done in healthcare workers and four in family or student clusters. The face mask trials for influenza-like illness (ILI) reported poor compliance, rarely reported harms and revealed the pressing need for future trials.
Despite the clear requirement to carry out further large, pragmatic trials a decade later, only six had been published: five in healthcare workers and one in pilgrims. This recent crop of trials added 9,112 participants to the total randomised denominator of 13,259 and showed that masks alone have no significant effect in interrupting the spread of ILI or influenza in the general population, nor in healthcare workers.
The design of these twelve trials differed: viral circulation was usually variable; none had been conducted during a pandemic. Outcomes were defined and reported in seven different ways, making comparison difficult. It is debatable whether any of these results could be applied to the transmission of SARs-CoV-2. Only one randomised trial (n=569) included cloth masks. This trial found ILI rates were 13 times higher in Vietnamese hospital workers allocated to cloth masks compared to medical/surgical masks, RR 13.25, (95%CI 1.74 to 100.97) and over three times higher when compared to no masks, RR 3.49 (95%CI 1.00 to 12.17).
… It would appear that despite two decades of pandemic preparedness, there is considerable uncertainty as to the value of wearing masks. For instance, high rates of infection with cloth masks could be due to harms caused by cloth masks, or benefits of medical masks. The numerous systematic reviews that have been recently published all include the same evidence base so unsurprisingly broadly reach the same conclusions. However, recent reviews using lower quality evidence found masks to be effective. Whilst also recommending robust randomised trials to inform the evidence for these interventions.”
(Source: https://www.cebm.net/covid-19/masking-lack-of-evidence-with-politics/)
CIDRAP (I’ll link here a podcast by Michael Osterholm, part of Biden’s pandemic planning team and one of the most extreme COVID doomsayers around):
“This issue of cloth mask use has been one of the toughest COVID-related issues we’ve had to deal with, because much of the discussion and consideration of use hasn’t been science-based but rather heavily influenced by misinformation, emotion, and even partisan politics. … Currently there is inadequate information to answer critical questions about how well cloth masks protect anyone from being infected or infecting others. …
Please know that the vast majority of information you’re hearing every day in the popular literature or even in the news about cloth masks is not coming from anyone with any expertise in aerosol science. It amazes and disappoints me how many of my professional colleagues have no real understanding of aerosol science and the physics of respiratory virus transmission, but are very willing to present themselves to the media as such experts. It would be like if I were brought in to the computer science world and because I have a PhD in environmental health I could make apparent authoritative statements about computer science. …
In the earliest days of this pandemic we knew that breathing air would be the main way the virus would be transmitted. We believed that there was a likelihood that this virus might be an aerosol transmitted virus, as we know definitively happens with influenza. Those who do not yet believe that influenza is transmitted by aerosols are just not current with the large body of scientific information available that shows just that. …
Never before in my 45 year career have I seen such a far-reaching public recommendation issued by any governmental agency without a single source of data or information to support it. This is an extremely worrisome precedent of implementing policies not based on science-based data or why they were issued without such data. …
I believe this cloth mask recommendation situation represented the other low point in CDC’s response to COVID-19 with the other being the failed testing situation. I have talked to close friends and colleagues who work at CDC and who were involved on the periphery with this issue. They universally disagreed with the publication of this recommendation based on the lack of information supporting that cloth masks actually reduced the risk of virus transmission to or from someone wearing a cloth mask. …
I urge you go online to the CDC website yourself and you’ll not find one piece of information supporting that cloth masks are effective in reducing respiratory virus transmission. Ironically, what you will find is that the National Institute for Occupational Safety and Health, an institute that is part of CDC, states on the CDC site the following; “A surgical mask does NOT provide the wearer with a reliable level of protection from inhaling smaller airborne particles and is not considered respiratory protection”; and “that leakage occurs around the edge of the mask when the user inhales.” One must logically ask, how can one part of CDC state that surgical masks do not provide adequate protection against aerosol exposure and then another part of CDC states we should use cloth masks to provide community protection from SARS-CoV-2 even though we know cloth masks are less effective in reducing the inhalation or exhalation of aerosols than are surgical masks.”
I’ll stop here but the interview is worth reading in full as it is extremely informative about both the level of evidence available and the political manoeuvering that led to mask recommendations. I’ll point out that only one study of note has been published since (more on that later) so despite the date on this it is essentially current with regard to the available evidence.
(Source: https://www.cidrap.umn.edu/covid-19/podcasts-webinars/special-ep-masks)
In addition to this interview, CIDRAP has published several other commentaries on masks — these are not systematic reviews but add an expert perspective on existing primary literature:
“If the data are limited, how can we say face coverings are likely not effective?
We agree that the data supporting the effectiveness of a cloth mask or face covering are very limited. We do, however, have data from laboratory studies that indicate cloth masks or face coverings offer very low filter collection efficiency for the smaller inhalable particles we believe are largely responsible for transmission, particularly from pre- or asymptomatic individuals who are not coughing or sneezing. At the time we wrote this article, we were unable to locate any well-performed studies of cloth mask leakage when worn on the face — either inward or outward leakage. As far as we know, these data are still lacking.
The guidelines from the Centers for Disease Control and Prevention (CDC) for face coverings initially did not have any citations for studies of cloth material efficiency or fit, but some references have been added since the guidelines were first posted. We reviewed these and found that many employ very crude, non-standardized methods (Anfinrud 2020, Davies 2013, Konda 2020, Aydin 2020, Ma 2020) or are not relevant to cloth face coverings because they evaluate respirators or surgical masks (Leung 2020, Johnson 2009, Green 2012).
The CDC failed to reference the National Academies of Sciences Rapid Expert Consultation on the Effectiveness of Fabric Masks for the COVID-19 Pandemic (NAS 2020), which concludes, “The evidence from…laboratory filtration studies suggests that such fabric masks may reduce the transmission of larger respiratory droplets. There is little evidence regarding the transmission of small aerosolized particulates of the size potentially exhaled by asymptomatic or presymptomatic individuals with COVID-19.” As well, the CDC neglected to mention a well-done study of cloth material filter performance by Rengasamy et al (2014), which we reviewed in our article. …
A cloth mask or face covering does very little to prevent the emission or inhalation of small particles. As discussed in an earlier CIDRAP commentary and more recently by Morawska and Milton (2020) in an open letter to WHO signed by 239 scientists, inhalation of small infectious particles is not only biologically plausible, but the epidemiology supports it as an important mode of transmission for SARS-CoV-2, the virus that causes COVID-19.”
Two more CIDRAP articles:
https://www.cidrap.umn.edu/news-perspective/2020/11/confronting-notion-face-masks-reduce-covid-dose
Finally, the agency which is widely considered to be the gold standard in evidence based medicine, Cochrane Reviews (this one published only 3weeks ago, November 20th 2020):
“ Medical or surgical masks
Seven studies took place in the community, and two studies in healthcare workers. Compared with wearing no mask, wearing a mask may make little to no difference in how many people caught a flu-like illness (9 studies; 3507 people); and probably makes no difference in how many people have flu confirmed by a laboratory test (6 studies; 3005 people). Unwanted effects were rarely reported, but included discomfort.
N95/P2 respirators
Four studies were in healthcare workers, and one small study was in the community. Compared with wearing medical or surgical masks, wearing N95/P2 respirators probably makes little to no difference in how many people have confirmed flu (5 studies; 8407 people); and may make little to no difference in how many people catch a flu-like illness (5 studies; 8407 people) or respiratory illness (3 studies; 7799 people). Unwanted effects were not well reported; discomfort was mentioned.”
I understand you are not a doctor, but rather than quoting Facebook groups which have a low barrier to entry and variable vetting of the information they post, it may have been worth your time to seek trusted scientific resources on mask efficacy before making statements like “[the studies] unequivocally … show that masks work.”
4. Sneezing and coughing
This is a minor point, but you mention that masks obviously work because we typically cover our noses when we sneeze. This is a fair point, we do do this. There are two main reasons why this has no bearing on mask efficacy. The first is that if something much easier to implement, like sneezing into an elbow (an elbow by the way is far less permeable than a mask and therefore physically a better barrier), works to stop droplets then there is no need for a mask. The second is that elbow-sneezing is predicated on the sneezer being symptomatically sick enough to sneeze or cough, but since the beginning of this pandemic people who have symptoms of respiratory illness have been told to self-isolate completely and to avoid leaving their homes. So if mask wearing is meant merely as a barrier for sneezes/coughs we shouldn’t need it at all, since public health advice during the pandemic has forbidden any exit from the home when experiencing symptoms. It would be disgusting and unsanitary to sneeze into a mask anyway, and carry the germs around in a soaking, contaminated mask. Once a mask is wet it should be discarded immediately so sneezing into an elbow, or a kleenex, is preferable.
5. Primary research articles (randomized controlled trials)
In what ultimately makes up the bulk of your video, you go on to “take down” some science articles purporting to show no efficacy for preventing ILI with masks. First of all, as a pedant, I implore you not to use language like “this is not a valid study” when discussing science, as “validity” in a scientific context has a very specific meaning; in fact, discussions of validity are usually divided into internal and external validity. Internal validity concerns whether the scientific method has been followed properly and is reproducible (you give no hint that this is not the case in the studies you critique) and external validity (sometimes called “ecological validity”) concerns whether a study explains a natural phenomenon adequately or can be extrapolated to the “real world.” You seem to have no issues with the reproducibility of the studies so if anything the critique might be that these studies are not ecologically valid, but almost by definition RCTs on human behaviour are not and can not be ecologically valid. Indeed, you are asking people to behave in ways they normally wouldn’t, for the sake of science. More on this later. I think what you mean by “valid” here however is “up to my personal standards”, and this is where the hypocrisy in your personal evidentiary standard comes in.
You provide 5 examples of studies which are “provided over and over” (by anti-maskers, presumably) in order to prove that masks don’t work and claim they’re invalid. You show on screen a list of dozens of studies from which you appear to have chosen these five as examples, but don’t link to the bigger list in the anti-mask resources provided with your video so viewers can only speculate about what the list contains. I won’t discuss these chronologically but I’ll make note of the order in which you discuss them. [Note for readers: all studies discussed here are provided in comments below the video, if you want to read them for yourselves.]
i. The third study you mention, Bae et al. (2020), is as you say retracted, so I wonder why you chose to focus on this one at all. It seems cheap to specifically choose a retracted study out of the dozens of non-retracted studies showing low mask efficacy. This is an extreme sort of cherrypicking.
ii. The other two according to you have two main issues. The first, Jacobs et al. (2009), followed 32 healthcare workers (HCW) over 77 days (you say this is too low a sample size, although considering that HCW are continuously exposed to viruses on a daily basis the trial length of 77 days seems sufficient to me) but ultimately only 1 participant per group got a cold. True, that’s fairly uninterpretable other than suggesting that perhaps healthcare workers are unlikely to contract colds in general. (It is worth noting here that in most hospital systems HCW are required to get a flu vaccine every season and tend to observe strict hygiene measures, so they may contract ILI at lower rates than the general population).
iii. The second, Canini et al. (2010), follows 306 participants in households during the 2009 swine flu and you claim the study isn’t “valid” because it was conducted over one year rather than the originally planned two years. You say this makes it “invalid” because the study could not be continued into a second year due to ethics concerns related to pandemic measures put into place by the French government. However this study followed 306 participants for 21 days, more than enough for a clinical trial, and had a staggeringly high total rate of infection at 49/306 participants ultimately infected. As you will see this sample size of infected patients (24 and 25 in groups of sizes 148 and 158 respectively) is actually huge for a study like this and is more than enough data with which to run a statistical analysis. I put this staggering high infection rate down to the fact that they had an actively ill household member as a basic inclusion criterion. There is no other reason given for considering the study “invalid” beyond the ethics committee shortening the trial at the conclusion of one flu season.
iv. There are two other studies you claim are not valid due to the “low” adherence of 56% in the mask groups and “high” adherence of 23% in the non-mask group in the first, and because kids slept in the same room as their parents in the second, respectively. While I struggle to see what is inherently invalidating about a study where multiple household members share a room (this is usual in many cultures and even in many western households — in fact this may make the study more ecologically valid, not less), I understand how variable mask adherence may be a problem for a study like this. It is not, however, unusual. More on this later (see point 6).
v. As your counterexamples to these “invalid” studies you provide three studies (I suppose we are to take it that they are “valid” studies not suffering from the same issues as the three above). In the entirety of your video these are the only clinical trials you discuss in a positive light so I assume this is the overwhelming, “unequivocal” evidence you speak of at the beginning of your video.
This pool of evidence is rife with problems from the get-go. I note that all three studies you cite as proof positive for masks working are by the same research group with the same lead author in the same geographical location, introducing a type of bias a scientist normally wouldn’t abide in a lit review let alone a meta-analysis. But this is not the biggest problem.
The bigger problem is the hypocritical double-standard you apply to the supposedly “not valid” studies and the 3 studies you hold up as apparently valid. Let me explain:
a. The first study you go over, MacIntyre et al. (2011), was not designed to test masks versus no masks. They do have a control arm (which is not very controlled; it is a ‘convenience’ arm where participants did whatever they usually do) which assumes a lower rate of mask wearing than normal in-hospital, but adherence was not measured and easily could have approached or exceeded the 23% threshold in the previous “invalid” study. In fact most of the analysis tables don’t even compare the n95 fit test, n95 non-fit test or medical mask groups against the control arm, just against each other. In one analysis all arms are compared against the convenience control group but there is no significant difference between the control and most of the mask arms. For laboratory confirmed influenza they find no difference between surgical mask and control groups, no difference between fit-tested n95 and control groups, and the only significant difference they find is between non fit-tested n95 and control groups. Why is this?
Well, it’s because there were no infections at all in the non-fit tested n95 group. For the other groups there were 3, 3, and 5 (fit test n95, surgical and control respectively) out of 500, 1000, and 500 n groups respectively.
There are two things to note here. First, you called the Jacobs et al. and Canini et al. studies “invalid” for having low sample sizes, but the Jacobs et al. had 1 and 1 and the Canini et al. had 24 and 25 infected participants. This study had 3, 3, 0 and 5. That is not far off 1 and 1 considering the size of the starting samples and is much smaller than 24 and 25 and thus by your own standards you should probably have likewise declared this study “invalid.”
Second, according to your own logic (explained later in the video) a fit-tested n95 should naturally work better than an unfitted n95, so finding a larger positive effect for an unfitted n95 (0 vs 3 infections) should suggest that deliberately unfitting your n95 mask has a larger positive effect, compared to fitting it properly, than wearing a properly fitted n95 compared to no mask at all (3 vs 5 infections). This makes no logical sense, but following your earlier point, we are dealing with really small numbers here. This is most likely a fluke.
Finally the authors themselves caution against interpreting this study as a comparison of masks and no-masks as the control group was, well, not very controlled:
“However, the convenience no‐mask group was not a randomized control arm and hospitals in this group were actually selected on the basis that most of their staff did not wear masks (which is not the norm in hospitals in Beijing), suggesting that conditions in those hospitals were different than those in hospitals from the masks groups. As a consequence, it is not possible to make any definitive judgement on the efficacy of masks on this basis.”
b. I’ll take your third ‘valid’ study first, for flow (MacIntyre, 2016). This one’s easy. It should be a gooder because it is the only study discussed so far to actually attempt to look at source control. Like the first study, which you claimed was “invalid” due to only 1 person per group having laboratory confirmed illness, this study also only produced one laboratory confirmed infection per group. This is very clear cherrypicking and a very clear double standard. You do nothing to explain why 2 infections make one study “invalid” but another “valid.” Moreover, the authors conclude:
“The study indicates a potential benefit of medical masks for source control, but is limited by small sample size and low secondary attack rates. Larger trials are needed to confirm efficacy of medical masks as source control.”
You go on to say that the authors’ conclusion about their own research is wrong, and that “the conclusion then, should not be that there’s no studies with verified outcome that shows a benefit, it’s that if you’re running a study on something that has a beneficial effect, and you do not consider … adherence … and your study is not blinded … you’re gonna see a lot of bias there.”
This is a weird take as the authors report in all their studies that self-report is the most valid method to determine adherence. It’s an even weirder take because, in fact, it does appear to mean that there are no studies with verified outcomes showing a benefit. At least you have not found any. All the “valid” studies in your video so far report no clear, verifiable benefit.
It is shameful to say you are “fact checking” a claim and showing “100% … unequivocal” evidence for your claim only to trot out the excuse that, while you can’t find any studies showing a clear benefit, it’s because the studies are badly done. Assuming there would have been a benefit shown with your preferred methodology is begging the question (and as you admit a couple sentences later, blinding is impossible in a mask study anyway). In the absence of evidence, you have to be ready to consider that your assumptions may be wrong.
c. Your second “valid” study is MacIntyre et al. (2009), which by your own admission is “not a very helpful study” and found no significant difference between P2, medical mask and non-mask arms. For some reason despite the study’s inability to disprove the null hypothesis you somehow conclude that it does, somehow, prove masks work. To be fair to this study it’s similar to the Canini et al. study both in its design and in the number of recruited and infected participants overall, and finds the same result (no difference in ILI following mask wearing). However this study is far shorter than Canini et al., as far as I can tell tracking mask wearing over only a 5 day period with a currently symptomatic, infectious household member. The study protocol doesn’t even look at mask wearing in the community, since the intervention arms only required adults to wear masks indoors at all times when in the same room as an infected child.
The authors also point out that:
“In this study, it is only possible to talk about a statistical association between adherent mask use and reduction in the risk of ILI-infection. The causal link cannot be demonstrated because adherence was not randomized in the trial. Although we found no significant difference in handwashing practices between adherent and non-adherent mask users, it is possible that adherent mask use is correlated with other, unobserved variables that reduce the risk of infection.”
The reason you seem to like this study is that they do a little regression modeling with ILI related to mask adherence, except adherence is measured simply in days (none, less than 2, 3, and 5 are the bins). How this relates to the low adherence percentages earlier in the study is unclear but you seem to be missing the bigger point here. Which is what studies like this actually say about adherence.
Adherence started at around 40 percent on day 1 and dropped to around 28 percent by day 5. Participants were not asked to wear masks after 5 days. More than half the users reported issues wearing the mask in just this 5 day period, the main one being discomfort, but including factors such as the children in the household being afraid/not liking the masks.
As you yourself admit, the authors consequently claim that “community use of facemasks is unlikely to be an effective control policy for seasonal respiratory diseases” but you wave away this point, claiming that COVID-19 is “a more deadly disease” than flu so maybe adherence will be higher in response to COVID-19 than the group in this study.
This brings me to my next point, ecological validity and feasibility….
6. Ecological validity and feasibility (and thus adherence)
I don’t know how you can possibly look at a set of studies all reporting low to medium high mask adherence (anywhere between 23 and 78 percent) even in hospital settings by healthcare workers, or over very short time-frames, and conclude that a COVID response requiring all citizens to wear masks in almost all settings for months to years will somehow result in higher adherence to mask-wearing. This is magical thinking.
A key principle of public health is that a certain level of nonadherence (and attrition of adherence over time) should always be baked into all public health responses. No HIV interventions expect 100% condom or antiviral use, and that’s a much deadlier illness. No reasonable public health scientist would ever expect above 60–70% adherence for an intervention as invasive as constant mask use, especially not over a long period of time.
(Moreover, it is well-documented that adherence to an intervention is usually increased by a number of factors including trust and respect between providers and patients, see article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1661624/ … forcing people to wear masks under threat of punishment does not increase trust or respect.)
Indeed this is mentioned in the 2019 WHO pandemic planning scenarios document (which says, by the way, “There have been a number of high-quality randomized controlled trials (RCTs) demonstrating that personal protective measures such as hand hygiene and face masks have, at best, a small effect on influenza transmission.” The WHO and CDC until just a few months ago had no qualms about claiming that the efficacy of masks is unproven and likely to be negligible. Why should we believe these agencies about masks now if we are to believe they were lying only a few months ago? If there has been a dramatic change in the state of the literature driving this about-face, why hasn’t it been explained? One source, BBC medical correspondent Deb Cohen, claims that a WHO contact told her “evidence had not backed masks but they recommended them due to political lobbying” — Source: https://twitter.com/deb_cohen/status/1282244773030633473)
This document, which up until a couple months before the pandemic started was seen worldwide as authoritative, even “expert” document on pandemic measures, states that mask recommendations are “Likely to be acceptable, but not appropriate in some circumstances and the adherence and compliance is low.”
(source: https://www.who.int/influenza/publications/public_health_measures/publication/en/)
Scientists already know mask adherence is likely to be low. This is a reason to avoid recommending them, as per the WHO document.
You claim that it’s different with COVID-19 than flu because COVID is more severe and non-seasonal. Calling COVID-19 non-seasonal is just plain silly as it’s followed a clearly seasonal pattern in every temperate region around the globe, but it’s also not particularly more severe than seasonal influenza.
The WHO themselves published a report in mid-October with an estimate of the COVID-19 infection fatality rate:
“Across 51 locations, the median COVID-19 infection fatality rate was 0.27% (corrected 0.23%)”
(Source (for PDF download): https://www.who.int/bulletin/online_first/BLT.20.265892.pdf)
The CEBM has a similar estimate of the IFR:
“Taking account of historical experience, trends in the data, increased number of infections in the population at largest, and potential impact of misclassification of deaths give a presumed estimate for the COVID-19 IFR somewhere between 0.1% and 0.35%.*”
(Source: https://www.cebm.net/covid-19/global-covid-19-case-fatality-rates/)
Influenza A is often estimated at around 0.1% but note that COVID-19 estimates are continuously dropping and will continue to drop as cases far outpace deaths. Simply put, COVID-19 is not so much more severe than influenza, so there is no reason to expect that it will drive up mask adherence to previously unforeseen rates. In fact, 9 months of real world data shows us quite clearly that it has not driven up mask adherence to near-100% rates, and mask adherence is likely to drop further over time. If masks were to work, at the population level, in the real world, they should work with imperfect use and at adherence rates of 60–70%, the upper bound in most studies you yourself cited. Expecting an adherence rate much higher than this is, again, magical thinking.
What you also seem not to have noticed is that this study of household transmission from children employed the one type of mask use that most public health bureaucrats have not even suggested implementing: continuous mask use within the home around family. We already know that household interactions drive a large proportion of COVID-19 transmission so if you really wanted people to ape this (inconclusive, 5 day long) study (with adherence dropping to 20ish percent after 5 days) you’d need to ask them to continuously wear masks in their own homes. Yes, even while sleeping if they sleep in the same room as a child, roommate, or spouse (note that study only required mask-wearing around one child with a confirmed infection, but here you’re suggesting them to prevent asymptomatic/presymptomatic spread, so you’d have to wear them around every household member at all times). Yes, even while eating and drinking water. Surely you realize this kind of intervention would have an approximately 0% adherence rate and would only further undermine trust in public health authorities if it was even suggested.
7. Cloth masks & other real-world considerations
Of course, none of this addresses the giant elephant in the room: Most of these studies are looking at n95s and medical grade masks, not the “fake” 1-ply medical masks or cloth masks worn by most of the general public*. I encourage you to look at the boxes of ‘surgical’ masks you see at the store. They will have a disclaimer on the box saying they are not for medical use/not suitable for preventing infections with viral pathogens. There is some physical evidence (as you mention later in the video) for potential efficacy of certain types of cloth or scarves, but RCTs for cloth masks are severely lacking when it is cloth masks that are mandated/recommended, and most common.
(Your favourite research group led by MacIntyre did look into cloth masks in 2015 and concluded: “This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection.”
Source: https://bmjopen.bmj.com/content/5/4/e006577)
Moreover, several of the studies you cite are dealing with symptomatic, actively infectious people who per current pandemic restrictions should be self-isolating at home, so catching sneezes or coughs should be a moot point. Symptomatic sick people are not the target of mask mandates. I think you’ll find most “anti-maskers” don’t take issue with currently sick people wearing masks if they are around other people.
Finally, mask adherence is not just an issue of percent adherence but of the quality of the adherence itself.
If the issue with mask adherence by the general population is due to their not wearing masks ‘properly’ (let’s assume for a moment that, despite the lack of conclusive evidence for anything of the kind, properly worn medical masks in medical settings do work well), how exactly do you propose proper, medical-style mask wearing by the general population will be achieved? This would require regularly sanitizing the hands and face and carrying around multiple sanitized masks per day, never touching them once applied to the face, removing and disposing of them in garbage bins/biohazard bins every 1–2 hours, resanitizing the hands and face immediately and again producing fully sanitized masks which never have to be readjusted. Children would have to do this too.
Consider for a moment that the vast majority of people currently wearing masks are wearing masks for entire days or re-wearing them days/weeks at a time, touching them constantly while wearing them, stuffing them in pockets/bags, not throwing them out after use and most importantly are for the most part only wearing them at all because it is mandated by the government and enforced by both businesses and police. This means that a significant portion of people not only don’t wear masks properly but don’t want to and don’t care. How exactly can proper medical mask use be enforced on the entirety of the population at all times when people are doing their damnedest to wear them in the least uncomfortable and intrusive way possible for the least possible amount of time?
(After 2 hours use in healthcare settings masks are fully contaminated, source: http://www.ijic.info/article/view/10788)
*You raise a point somewhere in your video where you note that most mask RCTs to date compare medical masks with n95s and not with a non-mask control arm. You ask if this is “malicious intent or a mistake”? It is neither. Most RCTs on masks are done in hospital settings where some level of mask wearing is the required norm, so of course the purpose of these studies is to see which type of mask is better and not whether masks should be worn at all. This is despite the fact that there is plenty of evidence in fact that mask wearing in hospital settings is likely pointless/unnecessary, as an aside:
(https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD002929/abstract
https://www.sciencedirect.com/science/article/abs/pii/0195670191901482
https://link.springer.com/article/10.1007/s12032-020-01403-8)
8. The one existing large RCT on COVID-19 and masks
You spend a lengthy section of your video lamenting that there are not enough high quality randomized controlled trials and claiming that if there were, they would show the efficacy of masks in the COVID context. However, at the very end of your video (after the video appears to be over in fact) you bring up just such a study — a gold-standard randomized controlled trial of mask use in the COVID context, in the community (not just hospital settings), with extremely high rates of adherence. I wonder why you buried this study at the end and devoted so little time to it when it is exactly the type of high quality evidence you seem to be looking for.
It does not suffer from any of the issues you brought up with any of the other studies you considered “invalid” — the sample size is large, the adherence rate was 93% (either perfect adherence or good adherence), the number of people ultimately infected was large, it compares a mask arm to a non-mask arm directly and these groups are randomized, it investigates the wearing of cloth masks in the community in the COVID-19 context, it was not halted midway through or retracted, etc. Finally, it has the advantage of being implemented in a context when other pandemic measures like lockdowns, social distancing, etc. are already in place, minimizing potential confounds and increasing ecological validity. What were the findings of this study?
“A total of 3030 participants were randomly assigned to the recommendation to wear masks, and 2994 were assigned to control; 4862 completed the study. Infection with SARS-CoV-2 occurred in 42 participants recommended masks (1.8%) and 53 control participants (2.1%). The between-group difference was −0.3 percentage point (95% CI, −1.2 to 0.4 percentage point; P = 0.38) (odds ratio, 0.82 [CI, 0.54 to 1.23]; P = 0.33). Multiple imputation accounting for loss to follow-up yielded similar results. Although the difference observed was not statistically significant, the 95% CIs are compatible with a 46% reduction to a 23% increase in infection.”
Startlingly, your takeaway from this is not that even gold-standard RCTs don’t find a statistically significant effect of masks on infection and thus that masks can’t be shown to work even with properly conducted studies. Instead, in~2 minutes at the end of your video which you devote to discussing this study, you completely invalidate everything else you have said throughout the entire video.
You claim that experimental evidence, in the form of a randomized controlled trial, on masks is completely worthless because the only way masks could work is if everyone in the community was wearing them. This would render all experimental studies on masks automatically worthless as they require a control and experimental arm, both with exposure to an infectious disease. Thus you create a bit of tautological reasoning for why masks could never be shown to work in an actual scientific study — making your claim that they work unfalsifiable, and thus tantamount to a superstitious belief. Yet again, somehow you have devoted a lot of time in your video to saying that the science does show they work.
Of course, your claim that masks don’t work if people around you aren’t wearing them is nonsensical. If a physical barrier works by stopping the spread of droplets as you claim, then it should work even if people around you are not wearing masks. You have a physical barrier on your face. It should stop virions from entering. You are essentially admitting here, at the end of the video, that you don’t think it is possible for masks to work in a protective capacity — so I wonder why you spend an entire video trying to show that they can?
Of course, if what you say is true and RCTs are worthless to determine mask efficacy, we still have another kind of experiment that we can look to for evidence on the efficacy of mask recommendations/mandates — population-level analyses.
9. Population-level correlational studies
Unfortunately these don’t show that masks work either. I won’t belabor the point but there are a few studies investigating whether various interventions at a country/regional level prevented viral spread or death from COVID-19. They find no overall protective effect of country-wide mask mandates.
“The use of face coverings initially seems to have had a protective effect. However, after day 15 of the face covering advisories or requirements, the number of cases started to rise. Similar patterns were observed for the relationship between face coverings and deaths.”
(Source: https://www.medrxiv.org/content/10.1101/2020.05.01.20088260v1.full.pdf)
Another study tried to correlate deaths to the BSG stringency index of implemented pandemic measures (including facial coverings) and found:
“Higher Covid death rates are observed in the [25/65°] latitude and in the [−35/−125°] longitude ranges. The national criteria most associated with death rate are life expectancy and its slowdown, public health context (metabolic and non-communicable diseases (NCD) burden vs. infectious diseases prevalence), economy (growth national product, financial support), and environment (temperature, ultra-violet index). Stringency of the measures settled to fight pandemia, including lockdown, did not appear to be linked with death rate.” [emphasis mine]
(Source: https://www.frontiersin.org/articles/10.3389/fpubh.2020.604339/full#SM6)
If population-wide mask mandates work you should also expect mask mandates to correspond in time with reduced infections/deaths. However, one can easily observe that there is no consistent relationship when mask mandate timing and death/case curves are overlaid:
(https://rationalground.com/mask-charts/)
Here’s a particularly amusing chart comparing Israel (blue) and Sweden (orange), which has recommended against mask use and avoided lockdowns/school closures:
No matter which way you slice the data, then, it seems impossible to honestly conclude that there is any evidence masks work either at an individual or population level.
Interestingly, mask mandates didn’t work during the 1918 Spanish Flu pandemic either: https://www.washingtonpost.com/history/2020/04/02/everyone-wore-masks-during-1918-flu-pandemic-they-were-useless/
10. Health risks of masks
You devote quite a lot of time in the video to a particularly insidious strawman where you ask whether mask wearing poses health risks and then (fail to) answer your own question by focusing exclusively on blood oxygen concentration in mask-wearers, as though this was the main (or only) health concern related to round-the-clock mask wearing. In reality we have very little evidence about the health effects of long term continuous mask use as even in hospital settings masks are rarely worn for more than a few minutes, or at most in the OR a few hours, at a time and not every day.
Besides the obvious ableism of dismissing people’s concerns about their lived experiences and feelings of well-being (when mainly less healthy people have issues wearing masks to begin with) this goalpost shifting is disingenuous to the extreme. There are many reasons why someone might not want to wear a mask which don’t even require a study — e.g., people, particularly rape victims or abuse victims, with PTSD related to covering their noses and mouths — but there are also well-documented and numerous health effects even when masks are worn properly, and particularly in the groups most vulnerable to COVID infection:
In COPD:
“Breathing frequency, blood oxygen saturation, and exhaled carbon dioxide levels also showed significant differences before and after N95 use.”
(Source: https://pubmed.ncbi.nlm.nih.gov/31992666/)
In pregnant women:
“Breathing through N95 mask materials have been shown to impede gaseous exchange and impose an additional workload on the metabolic system of pregnant healthcare workers, and this needs to be taken into consideration in guidelines for respirator use.”
(Source: https://aricjournal.biomedcentral.com/articles/10.1186/s13756-015-0086-z)
In people with lung issues:
“Importantly, we found evidence for significant respiratory compromise in patients with severe obstructive pulmonary disease, secondary to the development of hypercapnia. This could also happen in patients with lung infections, with or without SARS-CoV-2.”
(Source: https://eurjmedres.biomedcentral.com/articles/10.1186/s40001-020-00430-5)
In people with physical jobs:
“Ventilation, cardiopulmonary exercise capacity and comfort are reduced by surgical masks and highly impaired by FFP2/N95 face masks in healthy individuals. These data are important for recommendations on wearing face masks at work or during physical exercise.”
(Source: https://link.springer.com/article/10.1007/s00392-020-01704-y)
In epilepsy (also may be true of anxiety/panic disorders and asthma):
“While concrete evidence is lacking, if we consider that wearing a face mask may simulate hyperventilation, at least to some extent, we would probably avoid recommending this practice indiscriminately to all PWE.”
(Source: https://onlinelibrary.wiley.com/doi/full/10.1111/ane.13316)
In anyone who has to wear a mask at their job:
“Healthcare providers may develop headaches following the use of the N95 face‐mask. Shorter duration of face‐mask wear may reduce the frequency and severity of these headaches.”
(Source: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0404.2005.00560.x)
In various chronic diseases:
“Exercising with facemasks may reduce available Oxygen and increase air trapping preventing substantial carbon dioxide exchange. The hypercapnic hypoxia may potentially increase acidic environment, cardiac overload, anaerobic metabolism and renal overload, which may substantially aggravate the underlying pathology of established chronic diseases.”
(Source: https://www.sciencedirect.com/science/article/pii/S0306987720317126)
Impacts on thermoregulation, heart rate:
“We discuss how N95 and surgical facemasks induce significantly different temperature and humidity in the microclimates of the facemasks, which have profound influences on heart rate and thermal stress and subjective perception of discomfort.”
(Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7087880/)
“ Filtering facepiece without exhalation valve restricted respiratory heat flows.Caution is warranted when using N95 masks and exercising indoors to reduce stress.”
(Source: https://www.sciencedirect.com/science/article/abs/pii/S0360132319303622)
Considering that mask mandates currently require, practically, everyone including the ill to wear masks in order to go about their daily life tasks, and moreover require almost everyone with a physically taxing job to exercise continuously with a mask regardless of health status, and often require exercisers to wear masks during strenuous exercise when exercise is particularly necessary for the chronically ill and for maintaining a healthy immune system and metabolism, I don’t think these concerns can be dismissed as trivial. In fact even subjective perception of discomfort and pain on a continuous basis cannot be dismissed as trivial even in otherwise healthy people who have an 80% chance of completely asymptomatic illness even if they contract COVID-19 but are now being asked to live with indefinite chronic discomfort, pain, or worse.
There are also potential negative psychological and psychosocial effects of widespread mask wearing, especially on children who can experience delays in cognitive development due to lacking social cues and a corresponding decay in empathy. For example, masks introduce confusion into emotional communication:
https://www.frontiersin.org/articles/10.3389/fpsyg.2020.566886/full
Implying that the only possible health concern related to continuous mask use is blood oxygen saturation is not only tone deaf but a very dishonest characterization of people’s real, important concerns.
11. The physics of masks
You devote an entire section of the video to discussing the physics of aerosol and droplet spread but you miss a couple of obvious points here. First, it has been fairly conclusively established that droplet transmission is not the only/most significant mode of COVID-19 transmission, although the jury is still out on whether the primary mode is aerosol or fecal-oral (science papers lean toward aerosols as the primary mode of spread). Sources, if you don’t believe me:
“Asymptomatic and pre-symptomatic individuals, by definition, do not cough or sneeze to any appreciable extent. This leaves direct or indirect contact modes and aerosol transmission as the main possible modes of transmission. Much media attention has correctly focused on the possibility of direct and indirect transmission via for example contaminated hands, with public health messages focusing on the importance of washing hands thoroughly and often, and of greeting others without shaking hands.
Less attention has focused on aerosol transmission, but there are important reasons to suspect it plays a role in the high transmissibility of COVID-19. Air sampling performed by Booth et al. (2005) established that hospitalized patients infected with SARS during the 2003 epidemic emitted viable aerosolized virus into the air. Notably, that outbreak was caused by SARS-CoV-1, the closest known relative in humans to the SARS-CoV-2 virus responsible for the current pandemic. These viruses are not the same, but recent experimental work by van Doremalen et al. (2020) demonstrated that aerosolized SARS-CoV-2 remains viable in the air with a half-life on the order of 1 h; they concluded that both “…aerosol and fomite transmission of SARS-CoV-2 is plausible, since the virus can remain viable and infectious in aerosols for hours and on surfaces up to days.””
(Source: https://www.tandfonline.com/doi/full/10.1080/02786826.2020.1749229)
“In the absence of overt symptoms, such as coughing and sneezing, these observations raise the question of how infectious transmission is occuring. Ample literature reports that aerosol droplets <5 µm associated with normal breathing and talking and occasional coughing of healthy individuals predominate (Fabian, Brain, Houseman, Gern, & Milton, 2011; Johnson et al., 2011; Johnson & Morawska, 2009; Morawska et al., 2009). Furthermore, there is good agreement across the studies that normal breathing and talking result in size distributions of droplets with the majority, 80–90%, in the <1 µm range (Morawska et al., 2009). In short, from these and other similar observations, there has been growing acceptance in the daily public press and discussions among health experts that transmission occurring from asymptomatic persons is an important pathway (Asadi, Bouvier, Wexler, & Ristenpart, 2020; Lewis, 2020; Meselson, 2020; Morawska & Cao, 2020).”
(Source: https://onlinelibrary.wiley.com/doi/full/10.1111/risa.13500)
Other sources:
https://www.sciencedirect.com/science/article/pii/S0160412020319942
https://jamanetwork.com/article.aspx?doi=10.1001/jama.2020.4756
https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa1270/5898577
https://academic.oup.com/cid/article/71/9/2311/5867798
https://www.nature.com/articles/d41586-020-02058-1
https://time.com/5883081/covid-19-transmitted-aerosols/
etc…
If transmission is fecal-oral then constantly adjusting a piece of cloth on one’s face can’t help, but if aerosols are the main mode of transmission then there is no point whatsoever to wearing anything other than a perfectly fitted respirator, since aerosols are freely and easily expelled not just through the front of most masks but also through the top, bottom and sides. There are countless videos on the internet demonstrating this visually, if you don’t want to get into the physics. (E.g., https://www.youtube.com/watch?v=TkdTyZ9xd_g) As Michael Osterholm of CIDRAP mentions in the excellent podcast I linked above, this is key to understanding whether masks should physically work at all but you almost entirely gloss over the issue in the video, focusing instead on particle movement through the fabric of the mask itself.
Another issue worth mentioning is that the eye mucosa is also a point of entry for viral pathogens yet wearing goggles has generally not been seriously recommended by health officials.
It bears repeating also that insofar as you do discuss the physics of mask use as a physical barrier to viral droplets/aerosols, you fail to explain why this physical barrier would work one way only (as source control but not as infection prevention). This seems illogical.
You do cite a few studies showing that masks can function as a physical barrier effective against some droplets. I don’t want to get into details here as I think the point is moot regardless. I do want to point out that many studies find very low filtration efficacy for non-n95 masks in experimental conditions as well, so the science on this is also mixed and inconclusive — e.g.:
“The rates of all infection outcomes were highest in the cloth mask arm, with the rate of ILI statistically significantly higher in the cloth mask arm (relative risk (RR)=13.00, 95% CI 1.69 to 100.07) compared with the medical mask arm. Cloth masks also had significantly higher rates of ILI compared with the control arm. An analysis by mask use showed ILI (RR=6.64, 95% CI 1.45 to 28.65) and laboratory-confirmed virus (RR=1.72, 95% CI 1.01 to 2.94) were significantly higher in the cloth masks group compared with the medical masks group. Penetration of cloth masks by particles was almost 97% and medical masks 44%.” [emphasis mine]
(Source: https://bmjopen.bmj.com/content/5/4/e006577)
12. “Trusted authorities”
You bring up a number of points which have less to do with evidence for masks and more to do with what you perceive to be the faulty reasoning behind anti-mask views. One of these reasons is that anti-maskers appear to trust statements made by various self-styled experts, or even past statements made by self-styled experts who have since recanted.
First you mention that “authorities” such as Fauci have been called out for their about-turn on masks but that it’s fine because they were actually lying in order to “preserve” masks for healthcare workers. This is just plain disingenuous as HCW do not sew masks at home or buy them at the grocery store — they get them through completely different supply lines and the “medical masks” you can buy on amazon or at the store aren’t real medical masks anyway. This was always a nonsense excuse. Second it is bizarre to ask people to trust these same authorities after admitting they lied for months at the peak of the epidemic. Why should we then assume they aren’t lying now? If cloth masks work so well why didn’t they recommend them before massive viral spread occurred?
Second, you say that there are no doctors or medical authorities still not recommending masks now, even if they didn’t recommend them before. This is a plain lie. There are hundreds of scientists and doctors who have maintained that masks don’t work or are unlikely to work well continuously throughout the pandemic and continue to say so now. Among them are several national government health agencies:
“However, the Swedish Health Agency, largely behind Sweden’s no-lockdown strategy, has refrained from recommending masks, citing poor evidence of their effectiveness and fears that masks might be used as an excuse to not isolate when experiencing symptoms.”
(Source: https://www.reuters.com/article/idUSKBN28D1TH?edition-redirect=ca)
“When the prevalence of COVID-19 in society is as low as it is now, many people would have to wear face masks for the measure to have any measurable effect. With 100 new cases of infection in Norway in one week, 200 000 people would have to wear face masks in society for one week to prevent one new case. If this increases to 1 000 cases in a week, only 20 000 people would have to wear a face mask for a week to prevent a new case.”
(Source: https://www.fhi.no/en/news/2020/recommendations-about-face-masks/)
They also include the world’s most respected evidence-based medicine agencies (CIDRAP, CEBM, Cochrane), and well-respected scientists such as Stefan Baral, Jay Bhattacharya, Thomas Jefferson, Carl Heneghan, Sucharit Bhakdi, and many many more.
Finally you cherry-pick, again in what seems a most disingenuous fashion, a number of supposedly popular “anti-mask” doctors, professors and pundits (I haven’t heard of most of them) and proceed to undermine their expertise by pointing out that they are, e.g., chiropractors or “climate change denialists.” This is a weird tack for someone whose video series is called “not a doctor” as you seem to be dismissing the idea that someone who has socially unacceptable opinions about a different topic entirely, or is not technically an MD, can have and express an educated opinion about something which you then go on to express your opinion about. If your points were strong you would not need to resort to personal smears or guilt by association to discredit “anti-maskers.”
I will mention that Denis Rancourt is a former full professor at the University of Ottawa in physics with a VERY high H factor and a pretty spotless publication record in the field of physics, so he’s probably far more qualified to write a systematic review on aerosol physics than you, me, or any of the numerous pundits who weighed in on his supposedly lacking credentials. The fact that you mention he’s a physicist in your video as if it were a bad thing just shows that you do not understand what the mask issue is about on the most basic scientific level. A physicist is much better equipped to discuss mask efficacy than a medical doctor. Medical doctors are (usually) not scientists and most have no particular expertise on this topic.
You also mention that a “Dr. Eric Nepute” got slammed by the FTC for his charity work giving away vitamin D/saying it’s a treatment for coronavirus. While it may well be technically illegal to make specific claims about unapproved substances as a ‘cure’ for any disease, he is correct that vitamin D is one of the best evidenced prophylactic treatments/preventatives for COVID-19 (and is also very safe):
https://pubmed.ncbi.nlm.nih.gov/33146028/
https://pubmed.ncbi.nlm.nih.gov/32511549/
https://pubmed.ncbi.nlm.nih.gov/32474141/
So again, your intent seems to be to discredit this chiropractor as a quack when his apparent crime was giving away a useful supplement for free and running afoul of a technicality in the law while doing it. At least vitamin D supplements are shown to work much better than masks.
But real doctors who disagree with you get smeared too — in response to actual medical professionals who disagree with you on masks you say “I don’t know if it’s an attention thing.” After all your appeals to authority, you’re still happy to assume that you know better than people with far more expertise than you, so I wonder why you bothered to appeal to authority at all.
13. Other logical fallacies
Ultimately, this “fact check” suffers most profoundly from a lack of self-awareness. While explaining that medical doctors who disagree with you are either looking for attention or doing so because they approach the issue with pre-existing bias, you seem unaware that your own bias may be blinding you to reality. While you are accusing the many people involved in publishing peer reviewed research which you claim is inherently marred by author bias (and editor bias, and reviewer bias, I suppose?) of misinterpreting the evidence, you yourself misinterpret and twist the evidence you present.
Your narrative by the end of the video seems confused and internally contradictory — masks definitely, 100%, unequivocally work, but it is not possible to determine whether they work scientifically. You present zero evidence for their efficacy but this is because all studies to date are bad and all scientists are biased. Different studies are held to different standards, seemingly according to how closely they track with your pre-existing opinions. Good-faith messaging and outreach are paramount, but instead of addressing your opponents’ points you resort to mockery.
I’ll leave you with a little list of common fallacies of reasoning compiled by Dr. Vinay Prasad, a fairly balanced commentator on the COVID-19 crisis. A lot of these apply to your video, but learning to recognize and correct for our biases is the first step to better, and more honest, reasoning.
https://threadreaderapp.com/thread/1337624249297641472.html
As with what I’m responding to, I welcome responses/debunkings of my claims if any are forthcoming!
