How Much Mask-Wearing Do We Need?

Just how much mask-wearing do we need? That depends on how good our masks are. If they’re highly efficient, we can get by with fewer people wearing masks. If they’re not so great, we need a lot more people wearing them. Alan Kot has deployed a vast flotilla of Greek letters to come up with a theoretical model that produces this chart:

Each of these curves represents a disease with a particular value of R0 and shows what it would take to get R0 down to 1.0. COVID-19, for example, has an R0 of about 2.5, so take a look at that curve. On the bottom right, it shows that you can get this down to 1.0 with 100 percent of the population wearing masks that are about 35 percent efficient. At the top of the curve, you can achieve the same result with 60 percent of the population wearing masks that are 100 percent efficient. Anyplace else along the curve also works.

Fine. So how efficient are the cloth masks that we’re all wearing these days? I’m glad you asked:

The obvious problem with some of these is that, efficient or not, you’d barely be able to breathe through them. But how about silk or chiffon? They look to be about 50-60 percent efficient and are probably breathable. If we could get 80 percent adoption of masks like this, Kot says, that would be enough to get R0 below one and extinguish the the pandemic entirely.

Wear a mask! With the exception of 80 thread-per-inch quilter’s cotton, they’re all effective enough to make a difference.

UPDATE: I originally misinterpreted Kot’s chart. It’s corrected now.

HERE ARE THE FACTS:

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ONE MORE QUICK THING:

Our fall fundraising drive is off to a rough start, and we very much need to raise $250,000 in the next couple of weeks. If you value the journalism you get from Mother Jones, please help us do it with a donation today.

As we wrote over the summer, traffic has been down at Mother Jones and a lot of sites with many people thinking news is less important now that Donald Trump is no longer president. But if you're reading this, you're not one of those people, and we're hoping we can rally support from folks like you who really get why our reporting matters right now. And that's how it's always worked: For 45 years now, a relatively small group of readers (compared to everyone we reach) who pitch in from time to time has allowed Mother Jones to do the type of journalism the moment demands and keep it free for everyone else.

Please pitch in with a donation during our fall fundraising drive if you can. We can't afford to come up short, and there's still a long way to go by November 5.

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