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Comment by grey-area | Hacker News Reader

required everyone to wear masks in public of any type (this is rather important

Have any studies been done on this? It seems pretty tenuous to me and lots of assertions about mitigations (from drugs to masks) are being made just now without evidence.

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Yes. Lots of studies linked in https://medium.com/better-humans/whats-the-evidence-on-face-....

Turns out stopping droplets helps slow the spread of a virus that spreads via droplets. Shocker, I know.

Thanks for the link. The vast majority of the studies cited there are in fact in a hospital setting. I'm skeptical masks worn in the street are going to help more than distancing measures, though they'd probably help in crowded environments like public transport (along with hand washing).

Clearly the effects are at least cumulative. The lowest estimate for transmission with a homemade mask is 50% reduction, that's better than 100%

They are to be used in conjunction with distancing measures, handwashing, etc. They are not a replacement for it.

Here's one on homemade masks; they work better than nothing, not as well as surgical/N95: https://www.ncbi.nlm.nih.gov/pubmed/24229526

You definitely want to do both & ideally much more. But yet again, even even if mask provided zero protection, as long as it reduces spread from asymptomatic carriers, it is a big win. But for that everyone needs to wear them - which is happening here in Czech republic.

Just today a went for a walk through the second largest Czech city. The weather was nice and there were people in the streets, though a lot less than normally, with the usually crowded spots totally empty due to all the restaurants still being closed.

To cut things short, the number of people without mask I saw during this hour and a half walk that were not wearing a mask ?

Latest advice from the WHO is that masks are not useful outdoors unless you have symptoms.

https://www.theguardian.com/world/2020/apr/07/no-need-for-he...

More recent data strongly suggests that even people with no symptoms at low risk who have been sheltering in place should be wearing masks in public. I read an article over the weekend (which I unfortunately can't find now, although I found some similar ones) that described people on a plane with an infected passenger-- the rate of infection for healthy people wearing masks was literally zero, while those without masks was like 40%. I can't verify this now, but I have turned up a lot of articles describing how the official advice has changed on this.

I have a friend in a mid-size midwestern town in the U.S. whose mayor just put out a bulletin advising that everyone wear masks.

Similarly, there's at least one study out of China related to this recent outbreak showing the infection rate of the front line staff in hospitals (who were given N95 respirators) as zero, while the infection rate among other departments (radiology, etc) which were not wearing masks as much higher. That despite them calculating the front line staff having ~700% more exposure to the virus.

I know we want to study and confirm everything, but it seems like a real no-brainer that wearing a mask that filters droplets would reduce your disk of infection from an airborne virus generally spread via droplets.

And we're not talking about this in a hospital context, simply as harm reduction. As long as respirators are not an option for most of the general public due to supply issues, etc, then anything which reduces the infection rate is /better than nothing/, even if it isn't perfect.

I think you and others are making a lot of assumptions here - outside a hospital setting with trained staff and fitted masks to keep out virus-saturated air other vectors may be far more important.

There are reasons health experts around the world have not bothered to recommend general wearing of masks before other measures. Most people don't have the discipline to wear masks properly, not touch them, sterilise them, clean masks and all their clothes when they get in etc.

It is a mistake to think “wear a mask” advocacy is actually “wear a mask and do nothing else” advocacy.

It’s one of several things one should be doing.

There is no denying that wearing masks slows the spread. But how much do fabric masks with no filter, which allow most droplets through, slow the spread? I would appreciate any in reference to studies/indications on which fabrics might be appropriate.

https://www.ncbi.nlm.nih.gov/pubmed/24229526

> Both masks significantly reduced the number of microorganisms expelled by volunteers, although the surgical mask was 3 times more effective in blocking transmission than the homemade mask.

Stopping droplets entirely isn't as critical as slowing them down. That's why the homemade masks still require the six foot social distancing.

You asked for studies but you're going to get a bunch of Medium blog posts written by tech-bros who've half-read, and misunderstood, a bunch of research that says that masks don't really do much to stop droplets getting in nor getting out and that masks are probably not useful to prevent covid-19

There's a delusional belief on HN that the only way people are infected is by breathing in droplets, and all the other routes (fecal-oral, ocular, hand to mouth nose or eyes) are ignored, even those these are probably the main route of infection.

I'm sure you'll be citing studies that demonstrate this, right?

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