Paging Dr. Frischer: Face Masks
It’s been six months since the beginning of the pandemic lockdown. Yes, we are indeed getting smarter and more knowledgeable about the virus that caused this upheaval. However, it is clear that this ordeal won’t be over anytime soon. Whenever restrictions are relaxed, a bump in cases occurs. Are you aware that here in California, August was the virus’s deadliest month yet?
Facts tend to get muddled by politics, and clear messages can be hard to come by. Let’s look at the science behind wearing masks.
Here is the bottom line, so feel free to stop reading after this: The science shows that face masks work. The Centers for Disease Control (CDC) is clear that masks are one of the most important weapons for fighting the coronavirus pandemic. Masks absolutely reduce the transmission of respiratory droplets; an unmasked cough can send droplets some eight feet, and as much as 12 feet. Most of us have been using six feet as a guideline for physical distancing. Unmasked, that is simply not far enough.
Research does show that some masks are more effective than others. N95 masks appear to be best, but are still in short supply and needed by healthcare workers. Transmission can still be successfully reduced with simple and affordable alternatives. A recent study found that a three-ply surgical mask made of nonwoven material noticeably reduced droplets dispersed while speaking, coughing, and sneezing. As we might expect, a three-ply mask was more effective than one with two layers, and was far more effective than one layer. Homemade masks should ideally be made with three layers.
I am often asked about face shields. Studies have found that shields can significantly reduce the exposure to larger aerosol particles but are less effective against smaller particles, which tend to remain airborne longer. Therefore, the CDC does not recommend face shields for everyday activities or as a substitute for masks.
What about a neck gaiter (or buff), a stretchy cloth that extends below the chin? One preliminary study out of Duke University tested it and found that it did very little, and even worse, found that it dispersed large droplets into many smaller droplets, consequently increasing the droplet count and potential spread. More research is underway.
The CDC does not recommend facemasks with one-way valves or vents. These masks do filter incoming air, but allow potentially infected droplets to escape. These masks were not designed for the needs of a pandemic, where every single one of us needs protection.
The good news is that far more Americans are now wearing masks. Studies show that almost everyone, even those with chronic lung disease, is able to wear a non-N95 mask safely, without significant impact on their oxygen or carbon dioxide levels.
It’s helpful to know that contracting COVID-19 is dose-dependent; that is, exposure to a smaller dose can prevent the disease or lessen its severity. Facemasks greatly reduce the quantity of virus spread to others, and they do protect the wearer of the mask as well. However, all masks are not equal in their ability to prevent coronavirus spread. I urge you to wear surgical masks and/or well-fitting homemade triple-layer (or at least double-layer) masks. Of course, any mask is better than nothing.
The data is clear that this virus is very easily transmitted. Infected people without a mask can infect those around them, even those who are wearing a proper mask. Getting through this pandemic is going to require ALL of us to wear a mask. Let’s be team players and get through this sooner.
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