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Comment by jdlyga | Hacker News Reader

Masks aren't really an individual thing that will keep you safe if only you wear it, but it helps if you look at a population that wears masks vs doesn't wear masks. If masks are worn by a certain percentage of the population, it's been shown to put a halt to influenza pandemics (according to a paper posted late last week). It stops people from touching their mouth, and stops infected people from spreading their germs to others. It's one of the reasons why the coronavirus hasn't taken hold in Hong Kong more than it has.

The reason it's not been recommended in the US is because it's not really part of our culture, and so we don't have a huge supply of them. Medical workers need them the most. But if we did have enough, yes they're definitely recommended.

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Is there any evidence that masks stop healthy people from acquiring the virus? I think everyone agrees that sick people should wear one to stop it from spreading.

I'm also not convinced that a mask stops you from touching your mouth. Some experts are saying that it will actually cause you to touch your face more, and if the mask is not waterproof (are N95 respirators waterproof?) after less than an hour of wear the humidity of your breath will have created a large wet patch directly covering your mouth and nose. Now any time you touch a surface and then readjust your mask, you're planting more bacteria and viruses directly on that wet patch.

Masks, as most people wear them, don't do much. They'd need to be custom fitted to ensure no "leakage". The surgical masks do even less.

This is a very western approach the problem.

Even if the mask isn't perfect in protecting you, it's probably pretty good for protecting others when/if you are sick.

Containing your own viral spread is as important as protecting yourself when you think at the societal level...

Agreed

Especially because transmission can occur while there are no symptoms.

I touch my face and even chew on my fingers as a nervous habit (hey, better than smoking or vaping, right?). If a mask kept me from habitually touching my face I'd consider that a win.

> Masks, as most people wear them, don't do much. They'd need to be custom fitted to ensure no "leakage".

Respirator is the correct and less-confusing term for the item you're referring to.

Everyone should probably wear a surgical mask, because it will help contain the virus to those who have it, and help keep it from spreading. That's what masks are designed to do.

Wearing a respirator is overkill for most people, especially for everyday use, and therefore should be avoided because of the supply problems. They also have the usage complexities you mention. The fit tests verify fit, and are used help choose a well-fitting mask. I'm not sure how often the tests force someone to choose a different type.

I'm not convinced respirators are useless for regular people though, if you're a high-risk person in a high-risk area (such as an elderly person visiting an ER), I think their use might be warranted (coupled with more important practices like strict hand hygiene, etc).

They don't have to have an enormous effect on an individual to have a disproportionate effect on a population. If a virus has a reproduction number of 4, and a mask prevents 1/4 infections, ten generations of the virus will infect one million people in a non mask wearing population and 59,000 people in a mask wearing population. If we assume a 1% fatality rate that's 10,000 that aren't dead.

Moreover, it's significantly fewer people who are all sick at the same time. This means more available hospital beds. It means more time to develop better treatments. Less pressure on supply chains. Less societal impact from people who can't work.

It's at best marginally effective at reducing a person's probability of catching or spreading a disease. But in the face of potentially exponential growth, reducing that base by a few percentage points is a huge win.

That's why vaccines are incredibly effective despite being only 90% effective. Disease simply doesn't spread when 90% of the population is immune, no matter how virulent the disease is.

Even if they had zero ability to reduce wearers' risk of becoming infected when exposed, widespread mask use would presumably impede transmission by asymptomatic carriers significantly, which would have clear benefits I think.

Dont forget, if people are not accustomed to wearing masks, or if they are not fitted correctly - it will cause the person to be constantly readjusting, and touching their face more than if they didnt have the mask on.

I'm curious how much the type of mask matters. I have two kinds of masks for construction projects:

(1) the simple paper ones, and

(2) a fancier one with good rubber gaskets for my face, and replaceable filters.

Although the fancier mask (2) is more reliable for intake filtration, I suspect it's less useful for exhaust filtration, e.g. from coughs and sneezes. Because (2) uses a flapper valve to release exhaust, whereas the filtration in (1) is somewhat bidirectional.

> I'm curious how much the type of mask matters. I have two kinds of masks for construction projects:

There are surgical masks, surgical respirators, and regular respirators.

Surgical masks and surgical respirators meet regulatory requirements about blocking pathogens from the wearer, and I haven't seen any of that type with an exhaust valve.

I don't believe surgical masks do any filtration. They're simply a line-of-sight barrier. There's no seal, so hardly any air will be forced through it.

I'd expect a respirator valve to be at least as effective as that. If you were really worried, you could always wear a surgical mask over your respirator...

The reason it's not been recommended in the US is because it's not really part of our culture, and so we don't have a huge supply of them

It's a part of Japanese culture, and while they may have had a huge supply of them, there are mask shortages now. People there seem more upset about the price gougers than the mask shortage.

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