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Home » Face masks for COVID-19 – despite politics, science says they do work

Face masks for COVID-19 – despite politics, science says they do work

Last updated on September 9th, 2020 at 10:53 am

The latest battle in the world of the coronavirus pandemic is about COVID-19 face masks. Of course, the group led by President Trump, who think that the pandemic is irrelevant and face masks are some sign of weakness, eschew masks and scream at people in stores who try to enforce rules.

And there’s the other group, of which this ancient raptor is a proud member, which accepts the scientific evidence that face masks protect not only the wearer but also others from passing the coronavirus. It’s not a political decision, it is simply a public health policy that makes sense. It is altruistic. It helps us limit this pandemic.

Sure, it’s not the only way to do this – social distancing, hand-washing, and being diligent every time you leave the house along with face masks is how we protect ourselves and others from this virus.

This is just like the nonsense we see from anti-vaccine zealots – use pseudoscience or science denialism plus a healthy dose of some imaginary freedom that isn’t supported by any law or legal precedent. I, and many others, used to argue that the anti-vaxxers would see the errors of their ways if only they could see what would happen if any disease from our past – measles, polio, mumps, smallpox, rotavirus, or many others – returned as an epidemic.

Well, they went ballistic when New York tried to stop a huge outbreak of measles, with anti-vaxxers like Del Bigtree using anti-semitic imagery to stop mandatory measles vaccinations. And the anti-vaccine rabble are deep into the COVID-19 denialism. 

Apparently, the millions of infected people and hundreds of thousands of deaths mean nothing to the anti-vaxxers who overlap the COVID-19 deniers almost 100% on the Venn diagram of pseudoscience.  And that’s why we end up with a denial of face masks.

Recently, there have been several studies published that seem to have led to a solid scientific consensus – face masks work. It’s not political. It’s not an indication that you’re weak. It does not make you run out of oxygen. It doesn’t mean you’re a conservative or liberal. It just means you have chosen to protect yourself and others.

There shouldn’t be a battle over face masks, yet here we are. Let’s take a look at some of the science that seems to debunk the numerous myths about masks.

Face masks – a systematic review

A systematic review and meta-analysis were published in The Lancet by Derek K Chu, MD, in June 2020. The researchers examined the effect on physical distancing, face masks, and eye protection on the transmission of SARS-CoV-2.

Before we review this article and data, let’s take a step back and make sure that every reader understands what this kind of research is. Firstly, these types of reviews are literally at the pinnacle of the hierarchy of biomedical research. They represent data that is accumulated from dozens, maybe hundreds, of clinical or epidemiological studies rolled up into one neat package. They are not perfect, but they often are the foundation of the scientific consensus

Even though a lot of people conflate meta-analyses and systematic reviews (I do occasionally), there are different. Systematic reviews are reviews of the literature that uses systematic methods to synthesize findings of numerous other research studies using both qualitative and quantitative methodology. Systematic reviews attempt to answer questions by exhaustively summarizing the best current research evidence that has been published. It tries to eliminate bias and only include studies that meet objective standards like study design, statistical analysis, and other parameters. 

A meta-analysis, on the other hand, is a statistical analysis that essentially pools the results of multiple published peer-reviewed scientific studies. As more and more studies are added into the pool of data, the results become more and more stable, and outlying data becomes fairly obvious. 

A meta-analysis can be a part of a well done systematic review (as this study we’re going to review does), but it does not invalidate a systematic review if a meta-analysis isn’t included.

So let’s go back to the face masks review. I’m going to ignore the parts of this review that look at physical distancing and eye protection because they’re not the focus of my article. But suffice it to say that social distancing of about 1 m showed about an 82% reduction in risk along with a nearly doubling of the reduction per additional meter of distancing.

Eye coverings showed a similar risk reduction. So both physical distancing and eye protection show a statistically significant decrease in risk in COVID-19.

As for face masks, the researchers analyzed 29 unadjusted and 10 adjusted studies and found that the use of face masks was associated with statistically significant and large decreases in transmission for not only N95 masks (which are required to remove 95% of airborne particles) but also for disposable surgical masks and reusable 12- to 16-layer cotton masks. The authors stated that these masks and respirators reduce the risk of infection by 85%. Of course, they found that there was greater effectiveness in healthcare settings, as expected than in the general community. 

The authors concluded that:

…our findings continued to support the ideas not only that masks in general are associated with a large reduction in risk of infection from SARS-CoV-2, SARS-CoV, and MERS-CoV but also that N95 or similar respirators might be associated with a larger degree of protection from viral infection than disposable medical masks or reusable multilayer (12–16-layer) cotton masks.

Another recent systematic review published in the International Journal of Nursing Studies by MacIntyre and Chughtai found in a review of 19 randomized, controlled clinical trials, that the data suggests:

…that community mask use by well people could be beneficial, particularly for COVID-19, where transmission may be pre-symptomatic. The studies of masks as source control also suggest a benefit, and may be important during the COVID-19 pandemic in universal community face mask use as well as in health care settings. Trials in healthcare workers support the use of respirators continuously during a shift. This may prevent health worker infections and deaths from COVID-19, as aerosolisation in the hospital setting has been documented.

These are two powerful reviews of the current literature that seem to provide evidence that the use of face masks significantly reduces the risk of contracting or transmitting COVID-19. However, both articles make it clear that more data is necessary and that there are only a small number of high-quality primary studies that have been published.

What others are writing about face masks

Recently, two writers whom I immensely respect in the area of examining woo in medicine examined the use of face masks, and they both came down solidly on the side of pro-maskers. Pro-maxxers? I’m working on it.

Steven Novella, MD, wrote on the Neurologica Blog about masks, concluding that:

Pushing back simultaneously against the lockdown and mask wearing is mind-bogglingly absurd. It suggests that those who are engaged with such protests have not thought through what they want, even in the slightest, and are just acting out of pure emotion. Or, like some anti-vaxxers, they are in denial of scientific reality. They think the pandemic is a hoax.

Unfortunately, the choices of the uninformed or the profoundly confused affect everyone. Speed limits are not tyranny, because they affect others on the road, not just you. Smoking bans are not oppression, because your smoke can adversely effect the health of others. Public health mandates, when the science is clear and the benefit outweighs the burden, are not your choice, not if you want to live in society. If you think being told to wear a mask in order to protect other people from your germs is tyranny, then go live in a cabin in the woods.

Or – let’s just all listen to the science and stop making common sense health recommendations into a culture war.

And my fellow zombie enthusiast and Gloryhammer aficionado, David Gorski, MD Ph.D., wrote this recently at Science-Based Medicine:

The bottom line remains, though, that we have to learn to go with what we know, even in the face of uncertainty, even in the face of crappy retracted science papers, and even in this age of political division, and, right here, right now, there is more than enough evidence to suggest that mask wearing significantly decreases the risk of COVID-19 transmission. As Steve wrote last week, this is a marathon, not a sprint, and it is science that will eventually win the day. As I’ve said many times before, science as process can be messy, and in a pandemic every misstep, each of which would probably have made little stir if it were in a different area of science under different circumstances, will be magnified and politicized. We need to keep that in mind and view with caution each new discovery breathtakingly announced to the public.

And, yes, we need to wear our masks but, as Steve put it, continue to behave as though they don’t work very well. Eventually science will settle the issue, but until it does the balance of evidence supports routine wearing of masks. It’s also important to remember that masks are not the be-all and end-all. Social distancing, masks, and face protection all work together to reduce the risk of coronavirus transmission as low as feasible.


Anti-masks has a long history in the USA, going back to the 1918 flu pandemic when people complained about face masks with the same veracity as they do today. And they used the same type of logic we today, the Anti-Mask League “implored the (San Francisco) Board of Supervisors to grant ‘speedy relief’ from the ‘burdensome’ requirement” to wear masks. 

Anti-Mask League?

Yes, the evidence to support the use of face masks hasn’t reached the level of settled science, but the evidence is solid, its use is supported by biological plausibility, and public health agencies across the world think its a good idea. That’s pretty powerful support for its use.

In a recent article in Science

Airborne spread from undiagnosed infections will continuously undermine the effectiveness of even the most vigorous testing, tracing, and social distancing programs. After evidence revealed that airborne transmission by asymptomatic individuals might be a key driver in the global spread of COVID-19, the CDC recommended the use of cloth face coverings. Masks provide a critical barrier, reducing the number of infectious viruses in exhaled breath, especially of asymptomatic people and those with mild symptoms.

Surgical mask material reduces the likelihood and severity of COVID-19 by substantially reducing airborne viral concentrations. Masks can also protect uninfected individuals from SARS-CoV-2 aerosols and droplets. Thus, it is particularly important to wear masks in locations with conditions that can accumulate high concentrations of viruses, such as health care settings, airplanes, restaurants, and other crowded places with reduced ventilation.

That seems clear to me. And no, it is absolutely not a political issue.



Michael Simpson

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