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Comment by rumanator | Hacker News Reader

> There is currently a global pandemic afoot that is spread by droplets expelled from people's mouth and nose.

Do you have any source on how face shields are an effective tool against atomized covid19 viruses? The general guidance is that facial masks are effective at barring infected people from emitting contaminated particles, but not good at stopping healthy people from having contact with the virus. Therefore why would an open face shield, which filters zero, be a better solution?

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That's the general guidance in countries getting overrun by COVID-19. In countries which have stopped it, everyone wears facemasks. Chinese scientists have good data that surgical masks help in both directions.

Face shields reduce flow of air around you. Think of the six foot rule, but add a few more feet. They also reduce projectile sneezes (and "say-it-don't-spray-it" talking, coughs, and even breathing) by quite a bit. Think about sneezing in your elbow, only much better.

I hear mask promoters say the “it’s to protect others from you” line, only to turn around and say “masks are obviously useful, that’s why doctors wear them.” The truth is, mask use is built on incredibly shaky evidence, so it’s no surprise that now face shields will become part of the hype. Both may indeed be useful, but without a clear model of effectiveness, it’s hard to make good assessments.

Also, tin foil hats. You can't prove they DON'T work, can you? Even if they only add marginal protection, every bit counts. And they might, so can it hurt? This is why we are recommending tin foil hats to all Americans. That and a nice contribution from the tin foil lobby. We expect all Americans to commence procuring and constructing tin foil hats, and arguing about it on social media, and hope that this distracts them from noticing that their government is practically a failed state.

It turns out that "feeling safe" isn't the same thing as being safe, and feelings of safety will not actually effect infection rates, but Americans can't quite grasp that. And, hey, feelings of safety are about all we've got now, so.

You seem to conflate so many things here. Doctors wear mulitiple types of masks. Surgical masks (as are recommended for the general public) prevent a doctor from spitting on a patient accidentally (just as they prevent an infected individual from expelling virus laden spit droplets). Surgical masks provide limited (if any) protection from airborne droplets. Rather an N95 masks (with a seal and filter) is used. To make this effective to protect the wearer, goggles must also be worn. The general public does not wear goggles. Further,training on putting on and taking off masks is provided to medical professionals. Face shields protect from yet another class of dangers (splashing of contaminated fluid). The general public has little reason to wear these.

I thought the entire point of wearing a mask was precisely because we don't have clear evidence as to it's effectiveness. With such a degree of uncertainty (we are literally in the midst of an epidemic) it's not very practical to wait around for perfect information and evidence before you act

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