Hacker News Reader

Comment by obscura | Hacker News Reader

From what I read, these are only useful if you're sick and trying to reduce transmission. While they're better than nothing, they're not better than proper masks. [1] Isolation, social distancing, covering your mouth/nose correctly when you cough/sneeze and handwashing are more effective measures. [2]

I don't imagine that these DIY masks should be used more than once (as is the case with most masks), so you'll probably need to make a lot of them.

[1] https://www.researchgate.net/publication/258525804_Testing_t... [2] "Should I wear a mask to protect myself?": https://www.who.int/news-room/q-a-detail/q-a-coronaviruses

View on HN

> From what I read, these are only useful if you're sick and trying to reduce transmission.

Governments have been telling this, as well, but it cannot be 100% true. I supposed it was a white lie to prevent people from stockpiling.

Otherwise, there would be no use in medical personnel using masks.

I can understand that face masks might not be the best measure for healthy people, I can understand that they might not be super-effective, I can also understand that only certain types of masks are effective, but I cannot rationally believe all masks are completely useless.

Of course not all masks are completely useless. By "these" I was referring to the item of the topic, namely "DIY masks". They are only somewhat effective in preventing droplets being transmitted when you cough or sneeze. They are less effective in stopping you coming into contact with the virus because they simply do not effectively filter it out.

What medical staff wear are masks that are effective at filtering out viruses. Read this [1] on the FDA site for a good explanation.

It's well established that there's a global shortage of masks. [2] They're made in China and they can only make so many because the manufacturing requires special equipment. [3]

[1] https://www.fda.gov/medical-devices/personal-protective-equi...

[2] https://theconversation.com/the-global-effort-to-tackle-the-...

[2] https://www.npr.org/sections/goatsandsoda/2020/03/16/8149292...

Masks are complicated. There is a bunch of research on practical use of protective face masks, respirators and in that effectiveness showed to be massively reduced due to leaks, improper wear, moving them or taking them off because it's hard to talk in them, hard to breathe in them and so on. Masks that claim 99% don't necessarily improve much over an 80% mask or at all. DIY masks are not much worse for the same reason.

But at the same time masks is the only significant personal protection measure against this virus when you have to be in close proximity to other people. Literally any mask would help in such case.

> They are only somewhat effective in preventing droplets being transmitted when you cough or sneeze.

They are even less effective at that, than filtering stuff coming in.

Surgical-style masks are designed to catch droplets from the wearer, and therefore prevent the wearer infecting others. They are not useful in the reverse direction, only those other super-tight masks are.

So if you are healthy right now, you should probably not be wearing a surgical mask. However there is a use for healthy medical professionals wearing a surgical mask, which is to prevent them from becoming a vector for the virus as much as possible. Since a medical professional may see many patients in a day, and only days later learn that one of their patients was infected (and therefore they may be also), the surgical mask will be moderately effective at preventing infection of the numerous people they have seen in the meantime.

Hypothetically it would be great if we could all wear masks for the protection of others, such as they have been doing in Taiwan (amongst other places). However, the shortage of masks means that we should deploy them where they are most effective, which is medical professionals. (Taiwan actually mobilised their military to ramp up mask production, it’s not like they just magically had enough masks for everyone).

Surgical-style masks catch droplets going in either direction (of course) -- whatever protection it offers going out it offers going in as well, which is fairly obvious from a basic analysis. Of course it won't protect against individual viruses, but for many vectors that are not actually airborne but instead are in relatively large airborne droplets of fluid -- including this virus -- it can be of some use. Certainly better than nothing.

As a secondary benefit it stops you from touching the critical areas of your face. Given that we touch our face hundreds to thousands of times a day, a few adjustments of a mask aren't going to offset that.

The myth that the mask purely protects others is a myth that needs to die. At this point it is truly destructive.

Given that a surgical mask is only of limited protection, and not total protection, of course in actual contagion situations medication professionals should have something much better. Though we're in a situation right now where the CDC is telling medical professionals to fashion masks out of bandanas.

But when you see the streets of China where everyone is wearing surgical masks, or you see some old person walking around with one, note that it absolutely does reduce their risk. Not anywhere close to completely, but to some degree.

It is a nuanced issue though. There are recommendations from the World Health Organisation which say that in a community setting, for a well person “a medical mask is not required, as no evidence is available on its usefulness to protect non-sick persons“, but that a person with respiratory symptoms should wear a mask [1].

In a medical setting (or very close contact, like a few metres or so) they do help in both directions, this is standard “droplet precautions” one usually takes with a patient.

So while I agree with you that it does help in the medical setting, there is really no evidence that wearing a mask on the street protects yourself, rather than protecting others.

[1]: https://www.who.int/docs/default-source/coronaviruse/advice-...

> Governments have been telling this, as well, but it cannot be 100% true. I supposed it was a white lie to prevent people from stockpiling.

What I find crazy is (some) western governments complete inability to re-purpose (what's left of) their industries in a matter of days to produce needed masks and other accessories. You'd think there would be procedures already in place, but no, all they can do is monopolize re-sellers stocks for themselves. The inability of some so called first countries to handle that health crisis is a eye opener when it comes to how weak some western countries are. Where I live it's almost impossible to buy masks anywhere right now.

"From what I read, these are only useful if you're sick and trying to reduce transmission"

What government has said -- in a convoluted, almost misinformation manner -- is that from a probability perspective a mask is unlikely to be useful for an average person. They were saying this when the number of cases in the respective countries were single or double digit. But for front-line workers who by definition deal with a concentration of cases, it's much more effective and likely to be consequential.

But of course it's effective. It is a marvel that anyone seriously bought arguments to the contrary, and it is foolish misinformation that is going to plague us for years now.

See my reply to nisuni above. I was referring to DIY masks, which is what the topic is about. Masks are definitely critical for health professionals interacting with those who are sick.

I suppose so, though pre-edit certainly seemed to be masks generally, including a WHO statement on masks generally. Not to mention there have been some vigorous arguments on HN where people dismiss masks wholesale (including N95 masks).

Though while dismissing DIY masks, it's worth noting that the CDC is now telling actual front-line workers to fashion masks out of bandanas, etc. Anything that slows/scatters air is going to have some effectiveness.

New York state recommends masks for those age 70+ and those with compromised immune systems.

https://coronavirus.health.ny.gov/home

Reply on news.ycombinator.com