[davak]

I'm a critical care doc and directly involved with COVID administrative policies for my health system organization. I have recently told friends and family to start buying and wearing medical masks. Our experience is that medical masks are very protective in protecting the wearer from catching the disease. Hospitals have plenty of masks now. A cloth mask prevents spread away from the wearer, but a medical mask protects both the wearer and those around him/her.

Medical masks protect in two ways. One, they filter the air at an extremely high level. Two, they are fluid resistant, so the saliva droplets that are filled with virus particles cannot penetrate the mask.

Most health organizations, including mine, are noticing that COVID prevalence within their employees is less than the local population as a whole despite being around contagious COVID patients all day long. The major difference in these two populations is that health care workers are wearing medical masks.

[kyriakos]

What exactly is a medical mask? Is it the same thing as the cheap blue surgical masks?

[mariushn]

How often can one reuse a medical mask? What would be most effective use for prolonged life?

eg: wear a mask 20 min at a time, then change with another while leaving the previous in open air to dry. Cycle 3 masks like this. Total mask lifetime (until effectivity drops to <75%) with this usage pattern: 10 hours.

[btown]

What would qualify as a medical mask by your definition? Would this be distinct from a mask with N95 material?

[davak]

The primary difference in a medical mask and an N95 respirator is the tight seal that doesn't allow air around the sides. Unless you are in a high risk aerosolized environment, an N95 is unlikely to give you much additional benefit.

Most medical masks are made of the same material out of China that filters > 95% of infectious particles. If you want extra protection, you can look for masks with an "ASTM Level" that gives additional support that the mask is medical grade.

[URfejk]

How do you comment this then: https://videopress.com/v/4egEyh2b

[neckardt]

That seems to support parent's comment. The surgical masks prevented much of the smoke from going out the front, the "cloth mask he borrowed from his wife" let much of the smoke come through the mask.

Regarding the rest of the video, his claim of "masks have no effect" seems to be easily demonstrated as false from his experiments. Yes, some smoke does leak, but compare that to him exhaling without a mask. You would get a blast of vape smoke right in your face. The masks clearly filter some smoke and deflect the rest of the smoke away from where he's facing. While obviously not perfect, it looks like a clear improvement to me.

Finally, comparing smoke to covid-19 is disingenuous. You will almost never find individual virus particles floating around the air, they will instead be contained in water droplets which you exhale.

[URfejk]

I wonder how no one came out with a better version with some filter "installed"?

Is this the best we can do?

[neckardt]

You mean a mask which filters both on inhale and exhale? N95 masks do a decent job of that, although I'd guess there's still some leakage on exhale (not designed for that). N95s are still sold out in my area, so I got some KN95 which I use. The CDC tested some of them for effectiveness, many of them got pretty high marks: https://www.cdc.gov/niosh/npptl/respirators/testing/NonNIOSH...

[davak]

Some of the KN95s have been found to be counterfeit. Some of the ones we tested were no better than a cloth mask. When buying KN95s, please check that they've been validated by the CDC's list.

If it's legitimate KN95, it probably protects at least as good as a medical mask but probably not as good as a N95. This is because KN95s are not designed to form a complete seal so many folks will have some leakage around the edges. This is the reason that you see many systems 3d printing molded frames to improve the KN95 fit and decrease leakage.

[davak]

"Disposable" medical masks cost pennies to make, can be worn for multiple days, and are highly effective. In an environment where some folks refuse or can't mask, they are the most effective way for people to keep themselves safe.

By the way, I don't make or sell masks. I'm just interested in keeping people out of the hospital and my friends/family safe.

[dplgk]

This video only claims that YOUR mask doesn't protect others from your breath. This seems like a good reason for BOTH parties to wear a mask.

[mping]

Do people expect the air not to go anywhere...?

[lumberingjack]

You telling people to buy expensive masks. They're going to be used multiple times forwards and backwards sticking them in their pocket 20 times then touching it and touching everywhere else. That's why masks are dangerous because the wearers don't understand how to use them This is what my MOPP training taught me in the 90s and again in 2000s. WE WERE TAUGHT BY UNITED STATES MILITARY TO NOT HAND OUT MASKS IN AN EPIDEMIC WHAT CHANGED?

[true_religion]

> WE WERE TAUGHT BY UNITED STATES MILITARY TO NOT HAND OUT MASKS IN AN EPIDEMIC WHAT CHANGED?

The US military was the wrong place to look for a general solution to a civilian crisis.

All advise given from a military context relies on the idea that the civilian administration will step in, and coordinate, or handle things on its own.

For example, the military is advised not to do long term criminal investigations... but that’s not because detective work is valueless, but because it’s expected that the civilian police will handle that.