The controversy surrounding mask use and COVID19 is unnecessarily confusing.  The confusion comes from a lack of leadership, a lack of continuity and clear messaging, and a host of other reasons.  Before June 2020, the research was sparse. Scientific publications are now clearly are starting to reveal evidence that wearing a mask helps curb the spread of SARS-CoV-2, the virus that causes COVID19. The issue of wearing a mask is so vital that I will be updating this post as often as relevant literature is posted and available to me. 

“Wearing a mask could very well be your number one defense in avoiding COVID19.  In addition, wearing a mask associates with other useful behaviors such as not touching your face” 

As of today, June 14, 2020, the number of COVID19 cases in many states is rising. It’s not only due to increased testing.  The number of hospitalized patients and ICU beds occupied by COVID19 patients is also rising.  Whether you call this a continuation of the “first wave,” or the start of the “second wave” isn’t nearly as important as recognizing how critical it is to make every effort to curb the spread now.

What should be a clear cut case of objective public-health practice has simply become another hugely polarizing issue across the American landscape.”

In March of 2020, I collaborated with many doctors to write this article, it was read by nearly 10 Million people and helped explain why specific measures were necessary to prevent our healthcare system from being overwhelmed.  Much of what we said just 3 months ago is still very relevant today. 

Clearly, federal, state, and local governments are not going to close up their economies again anytime soon.  Where we go from here is up to us.  We need physicians and public health KOLs to speak up about the importance of wearing a mask in public.  We need to share the relevant scientific literature. The public is confused.  And confusion breeds distrust as represented by the rise in conspiracy theories, and folks claiming that their constitutional rights are being infringed upon. 

“Logic states that the needs of the many outweigh the needs of the few… or the one.” 

Of course, that was Spock. 


masks prevent COVID19 spread
Photo by Adam Nieścioruk


I’m a surgeon. The main reason I have worn masks for the last 25 years is to theoretically protect you from my germs, not to protect me from yours.  

Masks might save lives.  But the degree of protection you have, and the degree of protection you offer to others around you will depend on what mask you have, and how you wear it.

Also, masks might do a better job of protecting others from your germs — rather than protecting you from theirs. Let’s explore this further.  

What types of masks are there? 

  1. cloth masks
  2. surgical masks
  3. N-95 masks
  4. p-100 masks
  • The level of protection for both the person wearing the mask as well as those around you increases dramatically as you go down that list. 
  • Cloth masks are recommended by the CDC and now by the WHO, but as Michael Osterholm points out in his recent podcast on the topic; there is very little high-quality data to support the fact that cloth masks are protecting the person wearing the masks, or those around the person wearing the cloth mask. 
  • Surgical masks offer a higher level of protection, but they don’t hug your face thoroughly.  Air and water always follow the path of least resistance. So when you exhale, much of the air is heading out to the sides. 
  • An N-95 mask that fits tight and snug around your face has an excellent chance of protecting you and those around you. But N95 masks are in short supply, and frontline workers still need them.  Many companies are working on N95 masks or their equivalent to enable availability for public use. 
  • And a side note, don’t wear an N95 that has a valve in the front of the mask… those valves let your exhaled air exhaust unfiltered. That sends a concentrated stream of your virus particles to the people standing in front of you.  

Why we should consider wearing masks

COVID-19 spreads easily through a population because it replicates in your throat.  That means that it can reproduce and make hundreds of millions of copies of itself in your throat, even when you aren’t aware of it. This is referred to as the pre-symptomatic stage.  If a virus is replicating in your throat, merely talking will result in you spreading the virus.  Then, when you go outside, you spread those viral particles to people around you. 

When speaking in the context of the SARS-CoV-2 virus, just talking or breathing can spread virus particles. You do not need to be coughing to disperse droplets. 

Masks could work by decreasing the spread of these particles to others you pass in the store or on the street.  But as  I discussed above, that will depend on the type of mask you wear.  There is still a lack of evidence showing that a cloth mask will protect you. Yes, there are some mathematical computer models as well as some benchtop studies that suggest that cloth masks work, but there is no conclusive proof that a cloth mask will work to protect you.   But the absence of evidence is not evidence of absence.  In other words, we are just not sure.

The science is starting to show that wearing an appropriate mask could be a key variable in mitigating the spread of the SARS-C0V-2 virus.  To date, these studies have not broken down risk according to the different types of face coverings available.  One issue that is not getting a lot of attention is this; when you wear a mask you don’t tend to touch your face as often.  You shouldn’t touch it at all… but that’s a learned behavior and that’s hard.  People who wear masks might be distancing more than others. They might be washing their hands more frequently, but this is just conjecture on my part.  Masks are likely causing us to change other behaviors and the combination of masks and behavioral change is decreasing our risk of catching COVID19. 

The CDC recommends that a face covering is necessary in public to help prevent the spread of COVID19.  Yes, initially they said it wasn’t necessary. We can move past that. This is what happens when you’re trying to advise a nation in the setting of dealing with a novel pathogen. 


wear a mask
Photo by pixpoetry


Why does the CDC recommendation matter?  It could theoretically increase your risk.  Cloth face coverings don’t do a great job at filtering at really small particles such as a virus.  Some argue, certainly, a cloth mask is better than nothing? Right?!?  Well… are you going into places or placing yourself in social situations because you think that your cloth mask is protecting you?  If you answered that to the affirmative, then you may be putting yourself in harm’s way.  It is this overconfidence that you are being protected that might lead to harm.  Wearing a cloth mask should not give you the confidence of going into a crowded indoor space.  

Then again, we don’t need to block 100% of virus particles to decrease the risk of infection.  And the severity of a COVID19 infection might be related to how many virus particles you inhale, and how deeply you inhale them.  You need a particular “viral load” to cause disease. One viral particle isn’t going to do it.  So the more particles you block from getting away from your face, the less chance those around you have of catching the virus, and vice versa.   

Nevertheless, mask-wearing in the US is far from ubiquitous;   

  • Is it because people do not understand how important it is?
  • Is it because the messaging early on was unclear? 
  • I doubt it’s due to the lack of quality data since that didn’t stop the CDC from publishing its guidelines.  

I’ve heard many reasons. Very little surprises me these days. 

Despite the issues I articulated earlier, the CDC and WHO both recommend wearing a face covering.  The evidence that Michael Osterholm references should bring about a whole new level of conversation.  It should also spur innovation so that we can affirmatively say that when N95 equivalents emerge on the scene that people must be wearing masks to protect themselves and those around them. 

What should be a clear cut case of objective public-health practice has simply become another hugely polarizing issue across the American landscape.  


This paper was published in June 2020. It shows masks can reduce the spread of COVID19 by 40-60%.   

Face masks reduce the spread of COVID19 

How did we get here?  How did a mask become such a polarizing issue in America?  

As Dr. Bob Wachter recently pointed out in a thread on twitter, “mask-wearing has exposed many fault lines in American life.” Well.. to be honest, the entire COVID19 pandemic has widened the cracks that have been present on our landscape for hundreds of years.  The same regions with food insecurity, lower life expectancy, and less access to healthcare have been the very same areas suffering most from the COVID19 pandemic.  

Other issues which compound the mask-wearing disparity include: 

  • facts vs. emotion: facts have a hard time in our society now. Beliefs and emotions reign supreme in many circles.  
  • Protecting self vs. others: Masks often protect others from you.  They may protect you too, but many people are looking out for #1. 
  • state power vs. individual liberty

And the mask issue ratchets up the volume by adding yet another variable, vanity. 

Our politicians aren’t helping.  

Have you seen the videos of the senate hearings?  Many Democrats are wearing masks, and Republicans aren’t. Some politicians who face a tough election wear a mask at times, and at other times they don’t.  It’s silly. It sends a dangerous message. Where are the adults in the room?  Voters, even republicans, think that the president should be wearing a mask.  

Most recently, the white house press corps was asked to sit very close to one another in the Rose Garden during a speech by the president.  They admitted that it was done for appearances.  Face it; this pandemic looks terrible for the president. And for some reason, he and his “colleagues” believe that wearing a mask if somehow a sign of weakness.  This lack of leadership will result in harm because fewer people will distance themselves, or wear masks because they are following his lead.  


The CDC now recommends a face covering or mask in public.

But, but the CDC and Dr. Fauci said masks weren’t necessary???

Things change when we are dealing with a novel deadly virus.  Both the CDC and Dr. Fauci both recommend using a mask or face covering when distancing cannot be maintained.  Here is the link to the CDC page on guidance for masks or face coverings. 

I want to add once again, the research that a cloth mask will protect you is weak.  Yes, it may be better than nothing, BUT you should not be putting yourselves into social situations because you feel that you are being protected by wearing a mask. 

Wearing a mask, social distancing, and handwashing remain your best-combined methods to avoid catching the SARS-CoV-2 virus. 

Masks prevent the spread of COVID19
Click on the image to view the article.


What type of mask should I wear? 

There are three different realistic considerations.  The first is an N95 mask. If properly fit and adequately used, an N95 mask should block 95% of virus particles from reaching our face.  These are useful for frontline personnel who are dealing with COVID-19 positive patients all day long or are exposed to hundreds of people per day. 

A surgical mask MIGHT prevent anywhere from 60-80% of particles from reaching your face. But these are benchtop lab studies.  This does not account for the fact that air will take the path of least resistance towards and away from your mouth. That means that the air will travel around the mask and not necessarily through it.  So the actual level of protection provided might be far less. Again, we just don’t know what the accurate scale of protection is. 

A cloth mask might block a small number of larger particles, and that will vary based on the fabric used, its thickness, etc. 

But all of those mentioned above will block at least some larger droplets from leaving your mouth and entering the airspace of those people you will casually come into contact with when you are out and about.   Just talking alone allows droplets to leave your mouth and linger in the air in front of you. They might linger for 10 minutes or so. A lot of variables will determine how long those droplets hang around.  

Droplets and COVID 19 spread and why you need to wear a mask
Click on the image to read the article.


How do masks prevent the spread of COVID-19? 

This is an interesting video that models how we would limit infections in the US if different percentages of people wearing masks.  The concept is simple.  If you are infected, and without symptoms, you will spread the virus to many other people.  Some of those will get sick. Some of those will die. If this video doesn’t help convince you why you should wear a mask, then you do not need to read any further.  


Masks are awkward 

After living in Japan for a long while, I became very accustomed to watching people wear masks.  It took a while, but we weren’t facing a pandemic. Perhaps I would have been more understanding earlier on if we did face such a threat.  Some Americans perceive mask-wearing to be a sign of weakness.  There was a dramatic take-down on Twitter the other day when members of the armed services proudly showed their masks and boldly hinted that anyone who doubted their toughness or hinted that they were cowards were welcome to have an in-person chat :-).  

Would people think you were a coward because you wore a parachute, seatbelt or bicycle helmet?  I doubt it. 

When should I wear a mask? 

If you are out and about and cannot maintain a six-foot distance from people around you, then you should wear a mask.   Anytime you are indoors around others, you should wear a mask. If you are sick, then you should be wearing a mask at all times in your home as well.  If you are sick, you should NOT be going outside.  Again, you are protecting others from your germs.  

The key take-home is this… cloth face masks probably confer very little overall protection.  It might be better than nothing… but you should NOT be placing yourself into situations because you feel that your cloth mask is protecting you.  Social distancing and handwashing remain your best means of avoiding getting sick and avoiding spreading your germs to others.  


Disclaimer:  this information is for your education and should not be considered medical advice regarding diagnosis or treatment recommendations. Some links on this page may be affiliate links. Read the full disclaimer.

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About the author:

Howard J. Luks, MD

Howard J. Luks, MD

A Board Certified Orthopedic Surgeon in Hawthorne, NY. Dr. Howard Luks specializes in the treatment of the shoulder, knee, elbow, and ankle. He has a very "social" patient centric approach and believes that the more you understand about your issue, the more informed your decisions will be. Ultimately your treatments and his recommendations will be based on proper communications, proper understanding, and shared decision-making principles – all geared to improve your quality of life.

9 comments on “Masks Prevent The Spread of COVID19… the Evidence Is In

  • Great reading ,I learned a alot I will share this and Pray that people start wearing masks .
    Thank You

  • Dr Luks,
    I really enjoy your blogs and your tweets. Who produces your drawings/photos for your website?
    Thank you!
    P.S. please visit Craig Russell and I next year or when it becomes safe on our boat in Riviera Beach. I grew up in Pleasantville and Christine Carosella was my doctor for years! (AWESOME!) I recognized your name immediately as my ex-husband Scott Perlman is/was a patient. It’s a small world! Be safe and keep writing! We appreciate you!

    • Ah! That’s great! Such a small world. I use an artist from Portland for my images. She’s fantastic. Her name is Lorraine Yow.

  • Dr Luks,

    Thanks for writing this thoughtful and educational article! I’ve shared it with 20+ people so far!

  • i just want to say thank you for this post,i just hope everyone will read & wath this posting

  • I’m confused. Perhaps you can help? (I do wear a non-medical grade mask in public.)
    The video claims much higher effectiveness rates than I’ve seen elsewhere for:
    Surgical Mask – 56%
    Homemade – 2%
    I wear the Buff when hiking outside. Is it at all effective? or just a “feel good” courtesy?

    • I have updated the post… you may want to read it again. And I agree with you… a neck buff is more of courtesy. I would not assume that it is protecting you.

  • Thank you for this thorough article. As a dentist, our entire community always wear masks, gloves, eyewear and there has been no documented dental related case of Covid internationally, including Wuhan…per the CDC. Our common denominator is our surgical (not N95) masks…can’t wait for more research as we learn more about its transmission. I am most interested in the transmission from the asymptomatic carrier.

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