Are masks effective against the coronavirus disease?

do masks prevent the spread of coronavirus

There has been plenty of debate about wearing masks to help prevent the spread of coronavirus.  And with good reason.  At the start of this pandemic, we didn’t really have much scientific evidence.  And what little evidence we had involved other diseases, like the flu, which can’t be applied to the COVID-19 virus, SARS-CoV-2 or Coronavirus.

When this all got really bad, I was in Peru, desperately trying to get home the day before that country shut its airports.  I was traveling with a handful of other doctors, and none of us wore masks.  We were sure that anything other than an N95 was pointless.

But I was wrong.  We were wrong.  The WHO is STILL thinking wrong.  Because we were thinking backward.  We were thinking of how to avoid getting it.  But we should have been thinking about how to avoid spreading it.  

Because yes, if an infected person coughs in your face, you are likely to get infected unless wearing an N95 and face shield. But a simple cloth face mask turns out to be remarkably effective at keeping someone’s germs to themselves, especially during the presymptomatic phase of the disease. 

I’m not here to force you to wear a mask, or to call you stupid for not wearing one.  I’m just here to show you the evidence that changed my mind.  I hope you come to the same conclusion as I did:  We don’t have to choose between killing the economy or killing people.  With simple face masks in addition to hand washing we can eliminate the virus, reopen the economy, and save thousands of lives all at the same time.

This information was previously published on my personal FaceBook page. I’ve included some additional information specific to masks in the gym to tailor it to the readers of my blog. Here is a link to the original post on FB. If you have read that post and just want to see my new section on how this applies to the gym, you can click HERE.


The truth is that coronavirus is largely spread by respiratory droplets.  And homemade masks can block the majority of those droplets.  “Healthy” people infect just as many people as sick ones.  And places like Austria saw a 90% drop in COVID infection within two weeks of mandating masks.  So all of us should be wearing masks.  But please don’t take my word for it.  I’ve been wrong before, I’ll be wrong again.  Instead, look at all the evidence below.


First of all, we needed to realize exactly how coronavirus spreads.  This is primarily through respiratory droplets which are about 5-10 microns in diameter.  Studies tracing the outbreaks in China show that the transmission mode was primarily through these larger droplets.

Still we can’t rule out transmission through aerosols (droplets smaller than 5 microns). But, fortunately cloth masks can block both droplets and aerosols.

A study from Wake Forest (in publication) shows that home-made masks can block almost all droplets, including aerosols.  The better the material, the more droplets they block.  The best masks are made with two layers of batik quilting fabric, or else cotton backed with flannel.  These block even more droplets than a standard surgical mask, like the one I’m wearing in the photo on this post.

Surgical Masks vs Homemade Masks

Other studies have shown that unfitted surgical masks can drastically reduce the spread of the seasonal human coronavirus, a much less virulent cousin that causes mild colds. This study shows that even if aerosols and droplets emerge through the mask, they seem to have been filtered of all coronavirus RNA.

The following video demonstrates the effect on a scale we can see.  These droplets are bigger than the ones we’ve talked about so far.  I use it only to help visualize what the other studies show on the microscopic scale.

Percentage Reduction Matters

And its important to remember, that you have to inhale a certain number of live viruses to actually catch the disease.  That exact number isn’t known for COVID.  But 1000 is the best guess of virologists.  You may think “who cares if the mask blocks most virus?  All it takes is one and I get sick.”  But that’s not correct.

Blocking most of the virus droplets means the people around you are unlikely to inhale enough to get infected.  This is also why being outside is safer than in an enclosed area; the wind spreads your droplets around and people nearby are less likely to get hit with enough live virus to cause an infection


This is a frequent topic of debate.  Why should healthy people be made to wear a mask?  Well there is one major problem: up to half of those infected with COVID don’t know it, but can still spread it.  So you can’t really know whether you are truly healthy.  It’s an assumption of health, and it’s often incorrect.

In fact numerous studies have found that roughly half of COVID infections are transmitted between people before they know they are sick. (These are in process but so is the pandemic.)

This asymptomatic transmission is what accounts for people developing infections after lockdowns and quarantines are instituted.


Using all of these numbers, new models predict a vast drop in COVID cases with the universal use of face masks.  (I know models have been wildly inaccurate, but stick with me just a bit more.) Some actually show it to be far more effective than the economic shutdown we have been going through.  In fact they give us hope that with only 70% of the population wearing masks we could extinguish this disease before a vaccine is ever developed.  That’s something we can all be happy about.


Like I said, the last few months have been full of models and predictions whipsawing from one extreme to another.  And there are valid concerns that average people don’t know how to use masks or that masks might give us too much confidence, leading to unsafe behavior.  But we can look to real-life examples to provide evidence of the effectiveness of masks.  And that shows us that masks can be incredibly effective.  

Let’s talk about Japan (we’ve had 10 times their number of cases despite only being 2.5 times as large.) They’ve had no lockdown and closed no stores, but everyone wears masks.  And they’ve had days with no new cases reported.  But there could certainly be other reasons for their low case levels, such as total testing and differences in reporting.  Besides, you could argue that their culture is used to wearing masks and would use them more effectively. 

Learning From The World

So instead let’s look at Austria, a country with no previous culture of face mask wearing. They made masks mandatory in public starting April 6.  Two weeks later, infections had dropped by 90%.

Let’s look at the Czech Republic.  They required facemasks in mid March.  Within three days, the people produced enough masks at home for every man, woman and child, all 10 million. Coupled with their social distancing, this has kept the total cases in Czech Republic to one of the lowest in Europe, with only 50 deaths.

Similarly, Slovakia, the second country in Europe to implement facemask use has had some of the lowest cases and deaths in Europe.

Masks in America

And finally let’s look to America.  What happens when a hot zone institutes face mask policies?  Well Brigham and Women’s Hospital in Boston instituted universal masking of patients and staff, the rate of staff COVID infections dropped by 50%.

Other than that, it’s hard to say.  Our testing rates are low, case reporting and compiling vary significantly from state to state, and most states only require employees to wear masks when in contact with customers.  We really don’t have reliable data from which to draw conclusions.


While this seems like a reasonable and simpler solution at first, it is logistically impossible.  Most elderly people here live in multigenerational homes and can’t afford to live on their own.  Even if they stay home, their families will bring COVID home to roost.

And if we were to round them all up and put them in some sort of protective housing, well that too would be an enormous violation of civil rights.  Plus putting many high risk individuals together just means that when a care worker at this facility eventually infects somebody, we will have just set up a slaughterhouse and made the disease that much more likely to kill them all.

Plus you have the final piece in this puzzle.  Unfortunately it’s another one that puts egg on the face of the medical community and our assumptions.  It turns out that wearing an N95 mask is maybe not the best way to keep yourself from getting sick.  Having the infected person wear the mask is.  In a study published (and largely overlooked) in 2013 in the Journal of Aerosol Medicine and Pulmonary Drug Delivery, it was shown that even a simple surgical mask on a source of aerosol was better at preventing exposure than an N95 on the “healthy subject.”


Putting it all together, we should definitely all be wearing masks as much as possible in public.  Especially situations with high risk of transmission (office buildings, restaurants, parties, bars, nightclubs, public transit, gyms, and religious services). For more info on that, please read this incredibly informative article by Dr. Erin Bromage at Dartmouth

I’ll be the first to admit that the medical profession is playing catch up here.  And the inconsistent, conflicting messages have been very confusing.  Hell, I’m contradicting the WHO!  But I think the evidence is solid. And so do others:

Face Masks Against COVID-19: An Evidence Based Review


I know I sometimes think “I’d rather just catch this virus, get it over with and get back to normal life.”  I’m sure many of you do too.  Some think that risking infection is their duty to return the country to normal.  But that’s letting the virus win.  

Patriots make sacrifices, sure.  But not senseless ones.  And risking infection is an unnecessary sacrifice because wearing a mask, washing your hands, and keeping 6 feet away is the only sacrifice you have to make.  (Well, that and getting your brain tickled by the COVID nasal swab if you have symptoms.)

I hope you come to the same conclusion I did.  I hope we can all agree to make these accommodations.  For so long, it has seemed like we would have to choose between our people and our economy.  But with this new information, for the first time in a long time, I’m hopeful we can save both.


There are many reasons the gym or box poses a higher risk than other areas right now. People are breathing hard, often in close proximity, in an enclosed area. That certainly puts it into the high-risk activity category

Of course, you and I both know that exercise is good for your physical and mental health. We talked about that before. Maybe that protects you from a severe COID infection.

But even if you are one of the people that avoids a severe case, you can still spread it to people who aren’t so prepared. Your gym probably has at least a few older athletes. And even fit, healthy people have died from this disease.

High-Altitude Training Masks

So maybe it’s time to try one of the Altitude Training masks you’ve seen high-level athletes wearing? These masks are designed to limit oxygen intake, forcing your body to adapt to the added metabolic stress. They can help increase VO2 Max, red blood cell volume, hemoglobin levels, and mitochondria number and function.

As a fit person, you are more likely to be an asymptomatic spreader. But wearing a form-fitting high-altitude mask while working out can keep your friends safe. And it can enhance you aerobic capacity significantly. Win-Win!

You can take a look through this link on Amazon to find one. If you want to combine a new aerobic challenge while helping prevent the spread of COVID, look for ones with filtered exhalation vents (or un-vented) to help filter out any virus you may unknowingly be exhaling.

You probably know that my Amazon links often contain an affiliate link to help pay the bills on this website. But not this time. This is too important. You need to know that this post is all about us, working together, without any monetary benefit.

Stay safe my friends

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