5 ms·

I thought it's more like there's no evidence that show massive use of masks by the public is effective.

by schuke 7y ago

jacobolus 7y ago
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440799/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440799/ “Any type of general mask use is likely to decrease viral exposure and infection risk on a population level, in spite of imperfect fit and imperfect adherence, personal respirators providing most protection. Masks worn by patients may not offer as great a degree of protection against aerosol transmission.” https://www.ncbi.nlm.nih.gov/pubmed/19193267 https://www.ncbi.nlm.nih.gov/pubmed/19193267 “We found that adherence to mask use significantly reduced the risk for ILI-associated infection” https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006207.pub4/full https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD... “Surgical masks or N95 respirators were the most consistent and comprehensive [physical intervention] supportive measures.”
TallGuyShort 7y ago
It's complicated. It doesn't stop you from getting the virus if you get droplets on your hands and rub your eyes / nose / mouth, which is one of the more common vectors. So I buy that there's no evidence it stops you from getting the disease. But it does limit the droplets you spray out as you're speaking / coughing, etc. So IMO it would be part of a general solution to limit how much you spread the disease. But self-quarantine is easier to be sure you're doing it right. Wearing N-95 masks effectively is harder than just strapping it on, and the untrained are likely to touch their faces more while they're doing so anyway. I'd be surprised if everyone wearing a fresh mask properly and washing their hands properly before touching the mask or face didn't put a major dent in the pandemic. But that's just not going to happen anyway so we can't tell. I think the big issue is supply for medical staff. There's a limited supply of legit masks. Medical staff need masks more. We need medical staff more. And the masks are more effective with training / other procedures in place. Other than that - if the masks didn't help you, medical staff wouldn't wear them.
- ehsankia 7y ago
  This is the right answer. As someone who has the virus, it absolutely helps you not spread it. As someone who doesn't, it may stop a few droplets from getting into your system right at that moment, but said droplets can still get on your hands, and 30m later when you scratch your nose, you'll still get infected. So yes, with supply being low, it's far more useful for infected people to not spread said droplets.
  - stubish 7y ago
    The masks serve as a reminder to not scratch your nose, since it is covered. Glasses or sunglasses help for your eyes. Over here, supply doesn't seem to be low. Lots of smoke recently meant lots of masks in the supply chain. I'm surprised I see so few worn in the shops though, especially since I spent a lot of time in Asia where masks were common during flu season.
- solinent 7y ago
  Exactly: put quite simply the best mitigation measure is a mask, since it prevents most of the virus from getting into the air--the virus's primary medium of transmission. Even simpler--don't wear a mask for yourself, but for others.
rconti 7y ago
I hate to sound anti-science, but with something "spread by droplets" from coughs and sneezes and spit, where we should avoid touching our faces, it sure as hell sounds like even the most basic mask could be hugely helpful. They're trying to conserve masks for health care professionals, and DEFINITELY don't want people using "I'm wearing a mask" as an excuse to go out when they should just stay home, but I can't imagine they don't help a lot.
- watwut 7y ago
  It is the black and white thinking. The mask is either useless or perfect. The case where it would lower probability is considered "useless" cause it is not "perfect". Imo, this all or nothing thinking is contemporary issue that plays out in many contexts and we collectivelly really should get out of it.
- sjwright 7y ago
  For most people, regular hand washing and not touching your face is orders of magnitude more effective than wearing a mask. But as a society we've become addicted to off-the-shelf solutions rather than boring good habits. Basic masks can be beneficial for a short time. They need to be replaced at least every hour in order for the benefit to persist. This is routine in a hospital, but is simply impractical for most normal people. (If a mask stops a droplet containing virus, the virus doesn't disappear. Your own breath and fine droplets keeps the mask material warm and humid—making the mask material great environment for the virus to hang out and spread through the fabric until it can be breathed directly into your lung where it can do the most damage.)
  - CamperBob2 7y ago
    With a disease that spreads while asymptomatic, the droplets we really need to stop are the outgoing ones. A high level of even improper or suboptimal mask usage in the general not-yet-diagnosed population would be very helpful, because it would cut the six-foot proximity hazard zone down to inches. If we only had enough masks, that is.
A-Train 7y ago
There is evidence look at Asia. Everyone is wearing a mask and they control the virus. If you want to search for research based evidence there are plenty but focus on the research pre coronavirus - right now there is too much noise. One research suggested that with good handwashing masks reduce the infection rate by 75%.
bawolff 7y ago
I thought it was more, they are ineffective because most people put them on wrong.
- stubish 7y ago
  They are less effective, not ineffective.
entee 7y ago
N95 respirators have a pore size on the order of 100-300 nm. Viral particles can be a lot smaller than that (5-10nm), but this coronavirus seems to have a 80-90nm diameter. That means a respirator might be able to stop the particles IF worn perfectly (if you have stubble or a beard, you're already screwed). They will however stop droplets from someone sneezing or coughing, again IF worn properly. Medical professionals get fitted regularly to ensure proper fit. Masks are only effective in a fairly immediate radius: someone coughs, that droplet goes a little ways then falls on a surface. Medical professionals are in that immediate radius all the time, that's why they need the masks. People are usually not sneezing directly on each other, so that's less of an issue. What IS an issue is the viral particle that is now on a surface. You touch that, move your hand to your face (perhaps to adjust your mask) and bingo you're infected. Washing your hands obsessively is WAY more useful than any mask. Most of the time in medicine masks are used to stop the medical professional from contaminating the patient, not the other way around (that's what you see in surgery). If you're with someone sick, it would be good to give them a mask, they'll spread fewer particles that way. TLDR: Masks are minimally useful for the broader public, very useful for those directly in harm's way. Don't buy masks unless you're sick, or someone close to you is sick. Let the supply chain work for medical professionals who actually need them.
- isignal 7y ago
  Mask shortage is a red herring. I can tie a bandana or a scarf around my mouth. If it reduces my chances of breathing in a cough droplet by even 5%, that’s great. Why not?
  - entee 7y ago
    Go for it! Just keep in mind that the benefit there is pretty minimal. Probably not quite zero, but we're talking way less than hand washing. And if you touch your face more as a result of wearing the mask... That's not to say do or don't do it, just be careful. Handwashing and not touching your face are the single most important things to do.
    - isignal 7y ago

I thought it's more like there's no evidence that show massive use of masks by the public is effective.

by schuke 7y ago

I thought it's more like there's no evidence that show massive use of masks by the public is effective.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440799/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440799/ “Any type of general mask use is likely to decrease viral exposure and infection risk on a population level, in spite of imperfect fit and imperfect adherence, personal respirators providing most protection. Masks worn by patients may not offer as great a degree of protection against aerosol transmission.” https://www.ncbi.nlm.nih.gov/pubmed/19193267 https://www.ncbi.nlm.nih.gov/pubmed/19193267 “We found that adherence to mask use significantly reduced the risk for ILI-associated infection” https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006207.pub4/full https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD... “Surgical masks or N95 respirators were the most consistent and comprehensive [physical intervention] supportive measures.”

TallGuyShort 7y ago

It's complicated. It doesn't stop you from getting the virus if you get droplets on your hands and rub your eyes / nose / mouth, which is one of the more common vectors. So I buy that there's no evidence it stops you from getting the disease. But it does limit the droplets you spray out as you're speaking / coughing, etc. So IMO it would be part of a general solution to limit how much you spread the disease. But self-quarantine is easier to be sure you're doing it right. Wearing N-95 masks effectively is harder than just strapping it on, and the untrained are likely to touch their faces more while they're doing so anyway. I'd be surprised if everyone wearing a fresh mask properly and washing their hands properly before touching the mask or face didn't put a major dent in the pandemic. But that's just not going to happen anyway so we can't tell. I think the big issue is supply for medical staff. There's a limited supply of legit masks. Medical staff need masks more. We need medical staff more. And the masks are more effective with training / other procedures in place. Other than that - if the masks didn't help you, medical staff wouldn't wear them.

ehsankia 7y ago
This is the right answer. As someone who has the virus, it absolutely helps you not spread it. As someone who doesn't, it may stop a few droplets from getting into your system right at that moment, but said droplets can still get on your hands, and 30m later when you scratch your nose, you'll still get infected. So yes, with supply being low, it's far more useful for infected people to not spread said droplets.
- stubish 7y ago
  The masks serve as a reminder to not scratch your nose, since it is covered. Glasses or sunglasses help for your eyes. Over here, supply doesn't seem to be low. Lots of smoke recently meant lots of masks in the supply chain. I'm surprised I see so few worn in the shops though, especially since I spent a lot of time in Asia where masks were common during flu season.
solinent 7y ago
Exactly: put quite simply the best mitigation measure is a mask, since it prevents most of the virus from getting into the air--the virus's primary medium of transmission. Even simpler--don't wear a mask for yourself, but for others.

rconti 7y ago

I hate to sound anti-science, but with something "spread by droplets" from coughs and sneezes and spit, where we should avoid touching our faces, it sure as hell sounds like even the most basic mask could be hugely helpful. They're trying to conserve masks for health care professionals, and DEFINITELY don't want people using "I'm wearing a mask" as an excuse to go out when they should just stay home, but I can't imagine they don't help a lot.

watwut 7y ago
It is the black and white thinking. The mask is either useless or perfect. The case where it would lower probability is considered "useless" cause it is not "perfect". Imo, this all or nothing thinking is contemporary issue that plays out in many contexts and we collectivelly really should get out of it.
sjwright 7y ago
For most people, regular hand washing and not touching your face is orders of magnitude more effective than wearing a mask. But as a society we've become addicted to off-the-shelf solutions rather than boring good habits. Basic masks can be beneficial for a short time. They need to be replaced at least every hour in order for the benefit to persist. This is routine in a hospital, but is simply impractical for most normal people. (If a mask stops a droplet containing virus, the virus doesn't disappear. Your own breath and fine droplets keeps the mask material warm and humid—making the mask material great environment for the virus to hang out and spread through the fabric until it can be breathed directly into your lung where it can do the most damage.)
- CamperBob2 7y ago
  With a disease that spreads while asymptomatic, the droplets we really need to stop are the outgoing ones. A high level of even improper or suboptimal mask usage in the general not-yet-diagnosed population would be very helpful, because it would cut the six-foot proximity hazard zone down to inches. If we only had enough masks, that is.

A-Train 7y ago

There is evidence look at Asia. Everyone is wearing a mask and they control the virus. If you want to search for research based evidence there are plenty but focus on the research pre coronavirus - right now there is too much noise. One research suggested that with good handwashing masks reduce the infection rate by 75%.

bawolff 7y ago

I thought it was more, they are ineffective because most people put them on wrong.

stubish 7y ago
They are less effective, not ineffective.

entee 7y ago

N95 respirators have a pore size on the order of 100-300 nm. Viral particles can be a lot smaller than that (5-10nm), but this coronavirus seems to have a 80-90nm diameter. That means a respirator might be able to stop the particles IF worn perfectly (if you have stubble or a beard, you're already screwed). They will however stop droplets from someone sneezing or coughing, again IF worn properly. Medical professionals get fitted regularly to ensure proper fit. Masks are only effective in a fairly immediate radius: someone coughs, that droplet goes a little ways then falls on a surface. Medical professionals are in that immediate radius all the time, that's why they need the masks. People are usually not sneezing directly on each other, so that's less of an issue. What IS an issue is the viral particle that is now on a surface. You touch that, move your hand to your face (perhaps to adjust your mask) and bingo you're infected. Washing your hands obsessively is WAY more useful than any mask. Most of the time in medicine masks are used to stop the medical professional from contaminating the patient, not the other way around (that's what you see in surgery). If you're with someone sick, it would be good to give them a mask, they'll spread fewer particles that way. TLDR: Masks are minimally useful for the broader public, very useful for those directly in harm's way. Don't buy masks unless you're sick, or someone close to you is sick. Let the supply chain work for medical professionals who actually need them.

isignal 7y ago
Mask shortage is a red herring. I can tie a bandana or a scarf around my mouth. If it reduces my chances of breathing in a cough droplet by even 5%, that’s great. Why not?
- entee 7y ago
  Go for it! Just keep in mind that the benefit there is pretty minimal. Probably not quite zero, but we're talking way less than hand washing. And if you touch your face more as a result of wearing the mask... That's not to say do or don't do it, just be careful. Handwashing and not touching your face are the single most important things to do.
  - isignal 7y ago