Certainly the dumbest thing that’s happened during the COVID-19 pandemic is the politicization of wearing masks.
At the beginning of the pandemic, almost all authorities recommended against the public wearing masks. Anthony Fauci reports that the reason that the public was not told to wear masks was because of fears of hoarding masks among the public creating a PPE shortage for doctors.
Well, we had the PPE shortage anyway.
And now it looks like it was a gigantic mistake in hindsight not to recommend everyone wear masks from the beginning.
But how big a deal is this really? Just how likely are masks to reduce the spread of SARS-CoV-2?
Before we get into the numbers
The context here is really important. For the foreseeable future, COVID-19 prevention will require non-pharmacologic means.
In English: until we have a vaccine, we have to figure out how to reduce the spread of the virus with our actions rather than a magic pill.
This means the obvious - hand washing, physical distancing, not touching your face, and masks.
But sometimes it’s helpful to understand the numbers a bit more so that we can understand just how important these things are.
After all, wearing a mask is really unpleasant. Personally, I hate it. An N95 leaves marks on your face for hours. While wearing it, you’re stuck smelling your own breath, which, even if you just brushed your teeth, seems to smell like you’ve been without access to running water for weeks. Plus, the pressure on my nose seems to lower my sneeze threshold. It’s super unpleasant.
Surgical masks aren’t that much better. They irritate my face constantly. They make my breath smell only slightly better than an N95.
And the other parts of this can’t be underestimated. Masks make our interactions weird. We can’t see smiles and we can’t share meals together. The social impact of masks is not trivial, which I suspect is part of the reason why there has been a mask backlash.
So I wanted to learn (and subsequently write) about how big a deal masks actually are.
What do the numbers look like?
The Lancet just published a large, systematic review paper looking at all of the studies that have been published on coronavirus transmission.
The authors of this paper looked at 172 studies across 16 countries and 6 continents. It was an exhaustive analysis!
They studied all different types of scenarios. They looked at the impact of different types of masks in different types of settings - respirator, non-respirator, hospital, out of hospital.
So are masks really that big a deal?
Turns out that they are!
The risk in viral spread from wearing a mask is about 15% compared to not wearing one.
Respirator masks (N95s) are even more impressive, with about 4% of the viral transmission compared to no masks. When you take away the effects of N95s and just look at medical or reusable cloth masks, it’s closer to 33% of the risk (still a 67% reduction!).
There seems to be an interaction between the number of mask layers and the transmission risk. Meaning that if you’re buying a cloth mask, more layers = better.
The more compelling reasons to wear a mask
These numbers are clearly impressive. In fact, quite a bit more impressive than I would have expected. Across continents and populations, we see a consistent impact on viral spread from wearing a mask.
But your individual risk is only a small part of the story here.
The multiplicative impact of everyone wearing masks on transmission is even more remarkable. Meaning, if everyone wears a masks, these effects compound across society.
The converse is also true - if no one wears a mask, the risks geometrically increase across society.
Since you can spread the virus as an asymptomatic carrier, your actions may have consequences if you neglect to participate in this easy way of reducing transmission.
So in my opinion, the decision about wearing a mask comes down to a couple of things:
Uncertainty - you don’t *know* that you’re not infected. You also don’t know that the people you’re interacting with don’t have major risks for a bad infection such as poorly controlled diabetes, heart disease, or cancer.
Willingness to be part of a public health solution - until we have a vaccine, we’re stuck with behavioral means to stopping viral spread. Are you willing to inconvenience yourself to do your part?
We’ve all heard of the golden rule: do unto others as you want them to do unto you.
But with masks, the silver rule applies: do not treat people in a way that you do not want to be treated by them.
If you’d want people around you (who might be infected with COVID-19!) to wear a mask, do your part and wear a mask yourself.
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