Good, practical advice. Is he the right guy to be offering it?

#DYK? CDC’s recommendation on wearing a cloth face covering may help protect the most vulnerable from #COVID19. Watch @Surgeon_General Jerome Adams make a face covering in a few easy steps. https://t.co/bihJ3xEM15 pic.twitter.com/mE7Tf6y3MK — CDC (@CDCgov) April 4, 2020

Here’s what he was tweeting about COVID-19 at the start of February:

https://twitter.com/JeromeAdamsMD/status/1223586401280757762

Annnnd here’s what he was tweeting about masks by the end of February:

Seriously people- STOP BUYING MASKS! They are NOT effective in preventing general public from catching #Coronavirus, but if healthcare providers can’t get them to care for sick patients, it puts them and our communities at risk!

https://t.co/UxZRwxxKL9 — U.S. Surgeon General (@Surgeon_General) February 29, 2020

Why can’t our leaders talk to us like adults, wonders Matthew Walther? The “no mask” policy until now was obviously driven by fear that the public would hoard masks from doctors and nurses who needed them more urgently, not fear that masks didn’t work. Adams and the CDC could have been straight with us about that. We might have a smaller body count now if they had.

The 180-degree shift in acceptable public opinion about masks is in line with how the rest of this crisis has unfolded. Masks won’t help. Everyone needs a mask. It’s not worth shutting down travel to and from China over the virus, and Trump is just being a xenophobe here. Trump should have done more to prevent the virus from coming to these shores. It’s less dangerous than the flu; calling it less dangerous than the flu is a right-wing meme, perhaps even (one shudders) “misinformation.” Human beings can’t even transmit the virus directly to one another; it originated with animals in Chinese open-air “wet” food markets. Talking about the wet markets is racist, except when Dr. Fauci does it… We must put an end to the idea that the best way to get through this crisis is to say things we know are not true in the hope of getting people to behave a certain way.

The CDC webpage has been updated to say that, in light of the growing evidence that asymptomatic carriers are infecting others, “CDC recommends wearing cloth face coverings in public settings where other social distancing measures are difficult to maintain (e.g., grocery stores and pharmacies) especially in areas of significant community-based transmission.” That boldfaced “especially” is reportedly the result of a compromise between Trump’s non-health advisors, who feared that recommending masks would stir panic and wanted the advice limited to hot spots, and his health advisors, who countered that it made no sense to limit the advice geographically when we know it’s spreading everywhere. Where’s the logic in advising people to go unmasked and let them seed a major outbreak in areas that have been spared one thus far?

I wouldn’t worry about panic either. If 10 million unemployed and the prospect of 240,000 people dying hasn’t already driven people mad with terror, seeing shoppers with bandanas over their mouths at the grocery store ain’t going to do it.

By the way, not all fabrics are created equal in mask-making. A preliminary study tested how well different materials did in filtering out virus-sized particles of 0.3 microns. Result: You want woven, not knit.

The best masks were constructed of two layers of heavyweight “quilters cotton” with a thread count of at least 180, and had thicker and tighter weave. Lesser quality fabrics also worked well, as long as they had an internal layer of flannel. “You do want to use a woven fabric, like batik,” Segal said, “but you don’t want to use a knit fabric, because the holes between the knit stitches are bigger.”

A rule of thumb is that if you can see a lot of light through the material, viruses can easily penetrate. Presumably the technique demonstrated by Adams in the clip of folding several times to create multiple layers solves that problem to some extent even with a less tightly woven fabric.

Here’s Trump yesterday announcing the new CDC recommendation and … quickly announcing that he’ll disregard it personally. Because why avoid mixed messaging even on something as simple and useful as wearing masks?