Masks4All: Wear a mask to stop the spread of Coronavirus (Jeremy Howard)
masks4all.coSo, here's some information I've been seeing about masks.
1. After breathing in a mask for a while, the outside is now "potentially contaminated" with COVID19. Treat the outside of a mask as if it were infected.
Do NOT touch the mask while using it. Do NOT rub your eyes, etc. etc. Do NOT put on the mask backwards. It is recommended to color-code the inside and outside to make it easier to see.
2. There are a ton of discussions about how to disinfect a cloth mask. Kitchen equipment is commonly recommended. Boiling the mask, letting it sit in the oven for some time, etc. etc. You only need to raise the temperature to ~212F or so (boiling) to disinfect. (maybe lower, but boiling is easy because the bubbling water serves as a temperature gauge).
There may be easier chemical treatments, such as bleach when you're washing the cloth mask. But boiling is obviously safe.
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Note that "N95" masks are only 95% effective against viruses (even if you did everything correctly). Homemade masks will probably only reach 70% or maybe as low as 50%. You aren't invulnerable, you just have a layer of protection on.
I think this "home made mask" idea is very good. We need to leave the N95 masks for professionals, because the USA has a mask shortage (and N95 masks are disposable. One-time use).
Home-made masks can be reused through washing.
> Homemade masks will probably only reach 70% or maybe as low as 50%. You aren't invulnerable, you just have a layer of protection on.
This protection is more than the numbers may seem. See this essay on the benefits of contracting a disease in a smaller dose:
http://www.overcomingbias.com/2020/03/variolation-may-cut-co...
> The most directly relevant data is on SARS and measles, where natural differences in doses were associated with factors of 3 and 14 in death rates, and in smallpox, where in the 1700s low “variolation” doses given on purpose cut death rates by a factor of 10 to 30.
If you can cut the dose by 70%, it gives your immune system more time to ramp up ahead of the virus, which often translates into a more controlled infection with lower level symptoms, if any.
Do not boil or steam respirator masks. It destroys the material and renders it less effective, sometimes drastically so.
Instead disinfect them with dry heat in an oven or rice cooker. https://news.ycombinator.com/item?id=22680799
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3373043/
Perhaps my advice is specific to repurposed T-shirt masks then. But this study boiled the masks before testing and use.
The study was designed for poorer countries without as much infrastructure. Which is why the materials are so simple and the methods crude. But those attributes are very useful for the DIY community.
Here is an awesome technical video on using different methods to clean and reuse masks. Deals with Ozone, Alcohol, UV other disinfectants https://www.youtube.com/watch?v=2UdtKssU7po
"Note that "N95" masks are only 95% effective against viruses (even if you did everything correctly)."
There are masks that offer greater protection than N95. Among them are N99, N100, and various others. There's a good article that discusses some of the differences here: [1]
"N95 masks are disposable. One-time use"
Some types of N95 masks are disposable, others are reusable. Also, even the disposable kind could be (and have been) reused. This is, for example, widely done in hospitals where there's a short supply of masks, on the theory that some protection (even if imperfect) is better than no protection.
If there is a good seal, N95 will do better than 95% in almost all cases. The 95% is for the maximum penetrating particle size, i.e. the worst case size particle. This is typically about 0.3um. Particles that are larger or smaller than this will be filtered above 95%. If you want to nerd out on filtration theory, https://en.wikipedia.org/wiki/HEPA is a good place to start.
Per Chris Martenson[1], three reasons for every person to wear a mask:
- Stops infected people [including asymptomatic] from expelling infectious particles.
- Helps remind you not to touch your face [and precludes direct touch to mouth and nose--where mucus membranes are vulnerable].
- Much better chance of a low inoculum [a smaller initial viral load results in less severe symptoms].
> Helps remind you not to touch your face [and precludes direct touch to mouth and nose--where mucus membranes are vulnerable].
I like these instructional videos about how to put masks on and take them off, because they emphasize that you should be washing your hands when you put the masks on and take them off.
How to Put on a Surgical Mask: https://www.youtube.com/watch?v=jWnTCZWYOBw
N95 3M mask: How to Wear & Remove: https://www.youtube.com/watch?v=zoxpvDVo_NI
The mask won't do as much good if you just end up transferring the virus to your face after taking it off.
If the virus is present on your mask, it most likely would have already been in your body without the mask.
NNTaleb: Asymmetry: error FROM NOT wearing masks is vastly costlier than the error FROM wearing masks.
https://twitter.com/nntaleb/status/1244976894686179328?s=21
EDIT- I think I wasn’t clear— mask is critical protection, and the risk of infection from wearing one incorrectly is far lower than not having one at all. I was just responding to the final paragraph that the mask doesn’t do much good if transferred from mask to mouth during removal— very true, but it also reduces the quantity of the virus ingested.
> If the virus is present on your mask, it most likely would have already been in your body without the mask.
On the contrary. The virus is on the mask. That's why doctors / nurses wear masks, so that the virus gets stuck in the mask instead of in the doctor.
Now that the virus is on the mask, you need to treat it as if it were a contaminated object.
> Helps remind you not to touch your face
Hmm, I'm not sure about this one. Going to the pharmacy today, I noticed some people wearing masks, and just in the short time I saw them, many were adjusting/fiddling with their masks.
There is a definitely a learning period when you wear a new type of garment eg. suits or turtle necks, when you adjust a lot. Then you learn over time, and stop adjusting so much.
If you are concerned you will infect yourself by touching your face too much, just wear a mask at home for a few days, and get over the adjustment phase in a safe environment.
Mask will stop viruses getting through. Definitely adjusting mask is less hazardous than not wearing one and touching your face. Its interesting for me to just now notice how everyone constantly touches thier face all the time in some way or another.
In this attempt by the US government to stop this pandemic I found their suggestion not to wear mask the most disgenuine of all, especially knowing that countries with high mask wear awareness see this virus much more under control. In the same paragraph they already express they really need those masks for themselves so they don’t want you to hoard. Another argument was they only help when you sick. So all medical personel is sick? What a BS! Even more when they know you may be asymptomatic for up to 9 days.
The only thing I can think of equal to this would be if during HIV outbreak they were to tell you not to use condoms at all because study shows they don’t protect exact 100% times, and you can cut your member with your nail while you putting the rubber on, making it more prone to infections than when you’re actually wearing one.
Government really messed up on this one. Once the dust settles it will probably go into history books how our government suggestion not to buy/wear mask caused USA to be #1 in statistics.
To be clear, I'm not disputing that masks could stop people expelling or inhaling infectious particles - it's just the claim about not touching your face that doesn't ring true to me.
I do however think that, in general, masks are more needed by healthcare workers. They are on the frontline of COVID-19, and have no choice but to get up close to infected patients - most normal people are able to practise social distancing.
Quoting from the WHO/emergencies website[1]
> If you are healthy, you only need to wear a mask if you are taking care of a person with suspected 2019-nCoV infection.
The World Health Organization still recommends that you wear masks only if you're taking care of someone with COVID-19. Why is it so?
Like if the evidence is so clear, why aren't they advising the general public about this? (PS. non-native english speaker, ignore poor english)
[1]https://www.who.int/emergencies/diseases/novel-coronavirus-2...
When all is said and done a serious re-evaluation of the WHO’s mission and actions during this pandemic needs to take place. When the world needed them most, they failed spectacularly.
In mid January they said that China had no evidence of human to human transmission despite Taiwan telling them otherwise, probably due to political reasons. They refused to declare a pandemic weeks after it was clear it was one, and even now they still insist on ignoring the data we have around masks.
The WHO is, unfortunately, not a reliable source. They've repeatedly lied throughout the course of this pandemic. This is probably a well-intentioned one to preserve the global supply of masks, unlike previous lies which served only to make China look good, but the bottom line is that you shouldn't trust what they have to say.
CDC has said the same. Now people defend them saying they lied because they didn't want the public to hoard them but mask supply chains have been effected since probably January. I went to multiple Home Depots (upstate NY) end of February and they all told me they've been out of stock for more than a month. We couldn't hoard them even if we wanted to. Why even lie? It's pretty damn infuriating. Sk, HK, and Taiwan all have it under control because people there have been a lot more careful. They don't leave the house without a mask. Meanwhile in NYC, people were all casual about it up until maybe last week. Partly because of the delay in government response.
I myself have quoted the WHO and asked my friends not to wear them unless they're sick. Shouldnt have :(
Even in HN, until last week there were many articles linking to studies which said that surgical masks were not proven to reduce your chances of getting the virus.
Maybe to prevent a rush on surgical masks so that they are kept for health workers who need them the most?
That's another lie. Go to HD or Walmart and ask them how long they've been out of stock for. There was never a rush in the US. Healthcare workers should have their own supply from hospitals.
But then they could advertise using home made masks no?
Great website, I just have one suggestion. Before the message to wear a mask have in big red letters: "DO NOT GO OUT IN PUBLIC UNLESS IT IS ABSOLUTELY NECESSARY! No mask is more effective than simply not being around other people. BUT, if you absolutely must go out..."
Most of us on HN are well off and have the opportunity to WFH. Things aren't the same for the rest of the general public. All of those essential workers risking their necks for us should have access to masks.
Here is what the rest of the general public is also doing: “I also see people congregating on the beach that are completely ignoring what we’re doing,“ he said, “and I will remind these folks: You are being very very selfish because you are putting all of us, including our health care providers, at risk.”
from: https://www.politico.com/news/2020/03/30/maryland-shelter-in...
People are still going out and doing things around and with other people. And they shouldn't be, even with a mask.
To echo this, wearing a surgical mask consistently will maybe decrease your odds of getting Covid-19 by a factor of 3. That isn't the same as being immune so don't take unnecessary risks.
Yet, all we need to stop this is a couple 3x reductions in spread. Staying home is one path. Wearing masks another. We must not take risks, but we should all do what we can.
No, it's a reduction by a factor of 1000 or more. Doctors use them around infected patients and doctors aren't dropping dead like flies.
Most non-doctors aren't wearing eye protection and are probably worse at things like not touching their faces than medical professionals are. This is coming out of a WHO study from Beijingers during the original SARS outbreak who either surgical or N95 masks regularly. For untrained users it seemed that N95 masks were roughly equally as effective as surgical masks or possibly it is all about the droplet spread.
And also, lots of doctors and nurses are coming down with Covid-19 right now despite being careful about their use of PPE.
EDIT: When people first started talking about surgical masks versus N95 respirators one study that came up was this one[1] from Ontario which showed that a bit over 20% of nurses using either of them got infected with influenza over the course of a flu season. Infections happen unless extreme care is taken as with things like Ebola.
[1] https://jamanetwork.com/journals/jama/fullarticle/184819
With Covid-19 they are. One in Italy; 9 in the Phillippines; two in America; several in China. This is not normal.
Those cases cannot be conclusively linked to a failure of the masks to filter. Ergo, I'm not wrong yet.
That's not science; that's arguing to a point.
Presumably, these doctors didn't die during last year's flu epidemic. Nor during the previous years or decades of their practice. So something is different this year. Something they normally do to protect themselves, that isn't working this year.
Hm, they use hand washing, gowns, gloves, masks. Which one, do you think?
Please find a word that means "an ordinary piece of fabric that you can build yourself and wear if you're not sick".
At least in France, "Wear a mask" would be understood as "wear an FFP2, surgical-level" mask. The kind of masks:
* that we are in very short supply of at the moment (for various and sad reasons)
* that we have to save for doctors
* that everybody would try to buy on black markets if you asked them to use
* that we unfortunately told people not to try and buy (precisely because we need to save them for doctors because they are in short supply, etc...)
So if a campaign started today saying "wear a mask", with the intention of saying "cover your mouth with a piece of fabric that you made yourself if you're not sick", I suspect it would be counter-productive.
We need another word.
Very interesting linguistically.
My Argentinian wife tells me it's similar in Spanish - a mask would mean an N95 mask or similar. And a surgical mask would not be included if I understand correctly (they are not as good as N95 masks, they're mostly just a piece of fabric).
"Make a mask" instead of "Wear a mask". Build, don't buy?
Try translating using things like face-cover / mouth-cover / facial protection / facial protection equipment?
Homemade mask or bandana? Although the latter would probably not fit well over nose and mouth.
Just, please please please make sure they're home-made masks. If you have any professionally-created surgical masks, you should donate them to healthcare workers, who need them much more than you.
I live in Manhattan, and I still see people walking around outside with "real" masks.
"I live in Manhattan, and I still see people walking around outside with "real" masks."
Some people bought their masks long before the mask shortage, and hospitals don't accept donations of used masks.
Many of us already own and use 'real' masks, before the covid situation started. People absolutely have the right and the duty to protect themselves and those around them to the best of their abilities (without detrementally impacting others). While those hoarding, reselling at markup, and wasting supplies deserve any and all shame leveled at them, the quality of their PPE is in no way an indicator of such. Many are likely healthcare workers themselves.
Good point. Also, from the site:
> "Note: Please do not buy surgical or N95 masks because we need to keep those available for the doctors, nurses and first responders so they can stay healthy and care for the ill."
Kinda dumb point, since a healthcare worker is the one who gave me my single surgical mask in the first place. They don't want you to "donate" back a single used mask that your doctor gave you in the first place.
I don't think anyone is suggesting that you donate used masks, but you make a good point that we shouldn't assume that someone wearing a professional-grade mask is wearing one that should have gone to a healthcare worker.
They also don't want you to keep using a single mask for weeks on end, which is likely worse than not wearing anything since they're a breeding ground for bacteria. They aren't designed to washed, they're supposed to be disposable.
You can actually sanitize and re-use masks by baking them at relatively low temperatures.
"If your mask is not made of flammable material, Lin said, you can try putting it in an oven for 30 minutes at 158 degrees Fahrenheit, because the coronavirus is fragile. Doing so can kill off the virus, and “it doesn’t destroy the mask very much,” she said, adding that hanging the mask above a pot of boiling water for about 10 minutes could also help with killing off the virus, but it would need to be air-dried afterward."
https://www.huffpost.com/entry/reuse-face-mask-coronavirus_l...
Of course. But worse for who? The mask is at least partially to protect you from my probably not corona-virus related occasional cough (unless that bad cold which has left my lungs weak I had in January was covid), which is possibly spreading a bunch of non covid shit around every two weeks in my only public outing to the grocery.
Is there a site listing donation sites? I have a box of N95 masks from biking during wildfire season last year, and would like to get them to where they can be of use.
I feel like there's a good business here. Like T-shirts, I can see masks becoming another form of self-expression e.g. branded masks, funny slogans, etc.
This has already happened in HK, as Hong Kongers use masks to protect their identity and to express themselves during the protests
Quite a few already doing that.
I know over at coquetryclothing.com they used to decline to make masks due to possible liability reasons. Now they are making custom ones with all manner of fabrics.
Maybe after things have settled down. Right now, the right thing to do is to hand those out free to everyone, to normalize the safe behaviour. You can make your buck later.
Funky bicycle masks with colors or logos were often 30-80€ in 2016, and despite not being even FFP1. There is an opportunity, but there is also a feeling that health apparel should be bland and ugly if they are serious. It’s like wearing a suit at a programmer interview: Often a hint that one aspires more to the commercial side than the technical side, despite both being competent.
that's an interesting idea! I've seen personalized welding masks. You'd have to make sure it doesn't interfere with the functioning of the mask. Just producing them in different colors would be a start.
Interesting how the public opinion on this turned around as the virus spread. I wonder if this will lead to people in the west wearing surgical masks during flu season like people do in Asia.
While I agree, it wasn’t just general public opinion. In NYC at least, it was widely stated in the media by government officials and doctors that masks were unnecessary if you’re healthy, and actually could be bad because people were 1) removing surgical/n95 masks from supply, 2) wearing a cloth mask improperly sanitized can make you sick with other things. I like how Jeremy’s site has directly addressed those original concerns.
> In NYC at least, it was widely stated in the media by government officials and doctors that masks were unnecessary if you’re healthy, and actually could be bad
The WHO and CDC have been pushing that line as well. Studies linked to in the above article suggest that even home made masks provide some protection to healthy individuals. But even if they didn't, getting everyone to wear them would be extremely valuable for stopping the spread coming from people who don't know they have the disease. Also, "Don't come in hear unless you have something covering your face" is an easy rule for establishments to enforce, whereas "If you have Coronavirus you need to cover your face" is impossible to enforce.
Yet I've seen almost no leadership at any level in the U.S. pushing this (and this seems to be true in much of the West). Lockdowns buy us time, and we seem to be wasting that.
NYC government and health officials lied to NYCers when they told them that they should not wear masks.
does it have to be n95 to prevent spread? my understanding was the n95 rating protects you from infected people where a plain old surgical mask protects others from you. In other words, the n95 mask has what it needs to prevent you inhaling the virus where a regular mask has what it needs to prevent a sneeze or cough from escaping to the people around you.
Can you explain how that could possibly be true?
A surgical mask is just a simpler cheaper, less complete and less effective mask than an N95 mask, used in lower risk situations or when N95 is desired but not available.
https://www.cdc.gov/niosh/npptl/pdfs/UnderstandDifferenceInf...
Your understanding is incomplete. Both filter virus particles with different degrees of effectiveness. Viruses are typically most present in aerosolized droplets which are much much bigger than the gap size of a surgical or n95 mask.
> I wonder if this will lead to people in the west wearing surgical masks during flu season like people do in Asia.
Normalizing masks will also help fight facial recognition. IIRC, the Chinese systems have trouble with people who are wearing a surgical mask and sunglasses. No attention-grabbing dazzle makeup required.
Until the government bans masks in public places in the interest of, you know "public safety" once the covid-19 crisis blows over.
It sucks that we even need to think about wearing masks to escape facial recognition.
Wearing a mask in public is already illegal in many places[1].
It's been illegal in New York since 1845, due to some kind of violent conflict between landlords and tenant farmers. Some laws were targeted at the KKK, and newer laws were targeted at Occupy and Anonymous folks wearing Guy Fawkes masks.
This article[2] has a more complete list of state laws against masks, and where they've been overturned.
[1] https://en.wikipedia.org/wiki/Anti-mask_law#United_States
[2] https://www.businessinsider.com/countries-states-where-prote...
> Until the government bans masks in public places in the interest of, you know "public safety" once the covid-19 crisis blows over.
That's overly fatalistic. China hasn't banned them for that reason, and they're way more interested in that rationale than any government you're likely talking about.
> It sucks that we even need to think about wearing masks to escape facial recognition.
Avoiding facial recognition isn't just about avoiding the government facial recognition.
China has a comprehensive surveillance state that has fallbacks for cases when masks are not available.
They just make you take the mask off to identify yourself when relevant, I had to do this the other day while identifying myself for an immigration officer.
"Until the government bans masks in public places in the interest of, you know "public safety""
The government did this long ago, as a reaction to the KKK wearing masks to intimidate their victims and hide their identity.
So it's actually already against the law to wear masks in public in many places in the US.
I've never heard of this law being enforced in modern times, however.
The situation is a lot more nuanced than that.
I challenge you to find an example of a blanket ban on all masks, that doesn't rely on other factors like threatening violence, rallying, intent to hide identity, or a respresenting specific gang design/color.
'Intent to hide identity' sounds like a human right, criminalized. Unless asked by an officer, and even then in limited circumstances do I have to identify myself.
The only effective resistance is being in control of information dissemination to the masses.
Otherwise you will be marginalized and the masses will be "educated" by the mass media about how evil and troublesome "you people are."
Ensuring diversity in information dissemination is absolutely key to shooting down these proposals which harm personal freedom.
I live in Northern Ireland, and until very recently, if I saw a person with a mask on I immediately assumed they were up to no good.
My mother just finished sowing 100 washable ones so they can use them in the elderly care home she works in (she used the guide provided by the city of Essen, Germany). They still have some left but estimated they'll run out soon and asked for volunteers to sow them in their free time. She and a coworker combined to make about 200 in a couple of days which should be enough to cover all shifts.
While I was thinking about my homemade one I thought that steam ironing is probably a good and quick way to disinfect (for those that have an iron).
One thing often missed with the mask story is that they (generally) stop you touching your mouth and face as frequently. Assuming touching your mouth with a 'dirty' hand is a major infection vector, then a home made mask would indeed be of some use.
Hong Kong scientists also developed and tested a few home made designs, make of them what you will.
https://www.scmp.com/news/hong-kong/health-environment/artic...
US Surgeon General continues to recommend against this for some reason
I still find it difficult to understand if homemade masks actually reduce, due to all the different messages out there. Even the links provided in the Google Docs (https://docs.google.com/document/d/1HLrm0pqBN_5bdyysOeoOBX4p...) are more focusing on professional masks.
I even heard an "expert" saying on national TV that non-professional masks were worse, because the virus could actually stick to it :S
> for some reason
They recommend against wearing medical to help cull the shortage, and they recommend against wearing non-medical because they can provide a false sense of security, especially when worn incorrectly. Both very good reasons, IMO.
I just assume that anyone wearing a mask is doing so because they're infected, as per the recommendations, and I'm giving them a wide berth.
Not good reason. Lying to people to try to manipulate their presumed stupidity for their own good doesn't work. We went through this with the malarkey around claiming "advising abstinence is safer than offering condoms for STD protection"
Yes, but the messaging is not consistent which leads to public distrust, which might actually be worse. Don't wear masks, they don't help! But we need them because they do actually help! It's obviously not that simple but that's the way it's being perceived.
> which leads to public distrust
Maybe a minority, as there will always be, but I think most people are aware of the difference between medical and non-medical masks, and feel the messaging is consistent.
Definitely not - instead of emphasizing production the US has had this horrible no mask message - likely resulting in deaths
I've seen no evidence that masks give people a false sense of security. If anything, it seems to be the opposite. People report that when they wear masks, people move away from them, and employers have asked them not to wear them because they might make the customers feel unsafe. They're a giant reminder that things aren't normal and that we're in the middle of a massive pandemic. This is a good thing.
If mask use becomes mandatory, will there still be groups of people standing in the middle of supermarket shouting to each other? Sure, just like there are now. The difference is those people will at least have masks on.
>>> ...and I'm giving them a wide berth.
Another reason to wear a mask.
Non-medical masks don't keep stuff out. They just keep stuff in, so the only reason to wear it is to not spread your water droplets when you sneeze or cough. Medical masks keep stuff out, but are in short supply.
I think I'm helping more by going with the recommendations and not wearing a mask. Some people feel better wearing them, and that's fine too.
I think you might have misunderstood the parent comment (since your reply is somewhat of a non sequitur). My interpretation was that "if I wear a mask, then people will assume I'm infected and give me space, which is actually just better for me regardless of the mask's direct efficacy".
This binary assertion is fairly broadly given and I think it’s a narrow view that is a subtle form of unintentional disinformation that endangers. Any reduction of viral load on exposure is by nature better. The intensity of initial viral Old can help determine whether you get covid 19 and how strong it hits. It’s difficult to believe that some worth of cloth covering will have absolutely zero reduction of viral load. No you shouldn’t think it’s a comprehensive protection. But it’s silly to handwave away as useless as many do. Anything that limits spread should be encouraged. People still need to minimize going out, but if they have to, and have nothing else, dismissing all other masks as useless is not helpful.
I'm not so good with spreading my own potential risk around. It's essentially selfish to not wear a mask because 'it can't help me'.
Further, just yesterday on HN, there was a post about how a University study of airplane travelers showed mask-wearers got both benefits - they rarely caught anything and rarely infected anyone, even with the simplest masks.
False - hand to nose mouth contact is THE primary vector for this illness - masks are very effective in reducing this. Please stop spreading misinformation as it could lead to deaths.
> hand to nose mouth contact is THE primary vector for this illness
Do you have a source for this? It's contrary to most of what I've read (droplets through air is primary vector).
Droplets through the air is not primary vector - this is not aerosolized well like measels, the drops fall to the ground -> 6 foot rule is designed to avoid most droplets.
"In an adjusted analysis of compliant subjects, masks as a group had protective efficacy in excess of 80% against clinical influenza-like illness." -https://www.ijidonline.com/article/S1201-9712(08)01008-4/ful...
All the folks saying masks don't work literally never cite to any actual study - I think it's something like 90+ studies showing masks work and maybe 1 or 2 without a good result for masks.
I'm curious where you get the assertion that
> Droplets through the air is not primary vector
and
> hand to nose mouth contact is THE primary vector for this illness
In contrast, Johns Hopkins guide currently states: "Transmission - By respiratory droplets and by fomite. Virus found in respiratory secretions and saliva. - Viral shedding by asymptomatic people described, uncertain to what degree this occurs and abets transmission. - Stool shedding also described, but uncertain what role, if any, that plays." https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX...
Droplets through the air (that land on the second parties nose or mouth) is not what Hopkins is talking about. The virus is in respiratory droplets. If you sneeze on something its contaminated. If you touch your nose or mouth and touch something its contaminated. etc. If someone touches any of those surfaces (hard to avoid in a shared space with door handles etc) they risk infection.
In daily living you touch door handles, gas pump handles, elevator buttons, railings, subway hang straps and bars etc. Even before covid, how many people sneezed on you? Far fewer.
If we just were worried about folks sneezing on us we could stop washing our hands.
I'm not trying to argue about whether hand washing is important. I'm trying to increase my understanding of the transmission, and I hadn't heard before that touch face/nose/mouth is the primary way of the disease spreading as you stated. As you had said earlier in the thread: "Please stop spreading misinformation as it could lead to deaths". If you have a source for stating it is the primary method of transmission, I'd still like to see it. Otherwise, perhaps don't repeat that claim, in the interest of not spreading misinformation.
Here's the best article I've found on transmission, and a key excerpt. http://www.cidrap.umn.edu/news-perspective/2020/03/commentar...
> In risk communication guidelines for healthcare, however, the WHO states, "COVID-19 appears to spread most easily through close contact with an infected person. When someone who has COVID-19 coughs or sneezes, small droplets are released and, if you are too close, you can breathe in the virus" (emphasis added).9 But wait: Inhalation is not part of the traditional definition of droplet transmission.
> For healthcare organizations, the CDC recommends airborne, in addition to standard (contact) and droplet precautions, for the care of COVID-19 suspected or confirmed patients.10
> For the general public, the CDC describes SARS-CoV-2 transmission as primarily by droplets from coughs or sneezes, which "land in the mouths or noses of people who are nearby or possibly inhaled into the lungs" (emphasis added).11 But, again, inhalation is a new addition to the traditional definition of droplets. In contrast to its recommendations for healthcare, the CDC makes no mention of airborne transmission in public settings.
> The CDC admits some possibility that COVID-19 may be transferred by hands to mouth, nose, or eyes from contaminated surfaces, but notes that "this is not thought to be the main way the virus spreads."11
I'm not spreading misinformation. Most people don't bother to wear the masks correctly, and they provide a false sense of security and overconfidence.
Is the overconfidence documented anywhere, in terms of its effect? Is the problem avoided by having a reasonable sense of security?
I'd disagree with the false sense of security line. Why would someone who cares enough to go to the effort of wearing a mask then go and not wash their hands? A positive correlation between the two seems more likely than negative to me. Also this argument is trotted out regularly by "experts" in the car manufacturing industry whenever new safety technology is invented and as far as I can tell is always proven years later to be bullshit. For examples see seat belts, air bags, traction control, ABS, AWD.
If they recommended it, people would definitely hoard them. There isn't even a shortage of toilet paper, but people still hoard it.
In some parts of the US like NW Washington, toilet paper is in short enough supply that some households need to put non-trivial time and effort to get some.
It's hyper local. I got lucky and hit Costco in December. Feel like I still see it in stores sometime, but people need to shop around.
Acetaminophen is trickier now.
Totally uncorrelated. Surgeon general isn't recommending people but toilet paper.
They need the masks for medical professionals and first responders basically. Surgeon general is thinking about the greater good here.
See that the link is advocating for people to use homemade masks. They won't take way masks from health professionals. The base of the argument is that self-made masks are also useful and can help contain the virus.
Oh I totally agree that we need to make homemade masks.
It's stupid. N95 masks are in short supply and so should be reserved for healthcare workers and those caring for the infected but sugical masks can still help slow the spread. People should be weraring those in public. But the only messaging from the top is not to wear the masks
There seems to be evidence that masks can make your exposure worse by trapping some amount of air containing the virus under the mask, making you more exposed. If you are sick they can protect others around you, but if you are healthy, less so. In that context the flip of public opinion makes some sense: as we go from assuming most people are healthy to assuming most people are sick, masks for everyone in public can help.
Also, don’t forget that in medical facilities N95 masks are fitted specifically to individuals. You can’t just throw one on and be protected. Most people won’t go through the trouble of doing that properly. At that point it’s like putting your shirt over your nose: looks like you are protected but there are giant gaps that let in air.
> At that point it’s like putting your shirt over your nose: looks like you are protected but there are giant gaps that let in air.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3373043/
A cut t-shirt over your nose is actually quite good, so long as the pattern is somewhat tested. No, its no where close to an N95 mask, but even aerosol sprays can be somewhat mitigated with a simple cut t-shirt.
There are some internet studies suggesting an efficacy of 70% for T-shirts against 1-micron (bacteria) and 0.02 micron (viruses) particles. That's 6x worse than an N95 mask, but much better than unprotected.
EDIT: It seems like the flu (also a 0.02 micron virus) is primarily on water-droplets 5 microns in size. So we don't actually have to reach N95 mask levels for a major amount of protection, aiming at the 5 micron sized moisture bubbles is already going to help us severely.
I don't have any medical training, and speak only from perspective of common sense.
Your argument about trapping virus inside the mask is not very convincing. If you are putting a physical barrier between your respiratory system and air in high-risk areas (general stores, pharmacies and public transportation), then statistically there should be far more prevented contacts with viruses than trapped virus particles.
The incorrectly fitted masks should provide some benefit over no mask, so this doesn't seem as a good argument for not wearing masks. I would think that even putting shirt over nose gives some protection as it prevents touching face and diminishes odds of contamination with spit particles. Besides, the article is about home-made masks and not N95 masks.
The only convincing reason against masks is that they give false sense of security, so they shouldn't be the _only_ measure. Washing hands, wearing masks and physical distancing can only be beneficial.
"There seems to be evidence that masks can make your exposure worse by trapping some amount of air containing the virus under the mask, making you more exposed"
Where is that evidence?
"in medical facilities N95 masks are fitted specifically to individuals. You can't just throw one on and be protected. Most people won't go through the trouble of doing that properly."
Most people haven't been washing their hands properly either, and yet the government has gone to great lengths to educate people on how to properly wash their hands. There's no reason they couldn't do the same with mask fitting.
> Also, don’t forget that in medical facilities N95 masks are fitted specifically to individuals.
Lets not over-dramaticize N95 masks. An N95 mask is just 95% effective. Its not N99 or N100.
N95 is the relatively cheap and disposable mask. Its "custom fit seal" is the little metal bar that you push down on your nose.
Here is 3M's official fitting video. Its actually not very hard to use: https://www.youtube.com/watch?v=05wyH1-mLGk
Then elastic bands shove the mask against your face, forming an airtight seal. This can be effectively replicated with a decent hand-made mask solution (although the filtration of a hand-made DIY mask is much much worse, and completely untested compared to N95 designs)
Given the fact that we're in an N95 mask shortage situation, I think DIY home-made masks are the only solution for the general public. It just takes some scissors and a T-Shirt to make.
That's the first time I've heard about that theory about why wearing masks could be dangerous. Do you have a citation for that? I'd be very curious to read the study. Intuitively it seems like there's no way you could end up with a higher time integrated density of virions inside the mask than outside unless you put on the mask in a very contaminated area and then wore it into non-contaminated place. But maybe there's some mechanism I'm not thinking of?
Not an expert but I have never heard of this air trapping phenomenon, unless it is introduced by putting on the mask with infected hands I suppose. How would it get there in the first place?
There is evidence of efficacy in wearing even simple facemasks. Skepticism will lead your imagination to walk in circles [continuing without said mask].
I'm wondering about this myself. I mean I can understand not wanting to put pressure on the health system by adding extra supply, but homemade masks - even a bandana, must ad at least some protection.
Even if it only reduces R0 by a few procent that would mean a lot?
They say it creates a false sense of security, which makes people more careless, which spreads more infection.
The cure for misinformation is information. People can learn to wear masks correctly.
They recommend against it, because recommending the use of masks would expose the universal lack of availability of even basic surgical masks. The on-demand system in the US cannot cope with events like this (no stockpiles).
So, they're recommending we don't use masks, so that more masks are available for medical professionals, so that when most of us get sick via community transmission (because we don't have masks), the medical professionals can also run out of masks while they treat us.
Just a nit - mask production could have been ramped up throughout January and February, by executive order if necessary, if the virus had been acknowledged as a threat instead of simply being ignored for two months.
They seem convinced it will create a run on masks, leaving none for medical staff. Even though this message is clearly about home-made ones.
Has the mask supply situation improved? I still see empty shelves for things like gloves, sanitizers, etc.
The lack of masks and testing in the US is a colossal failure. It's not like a pandemic scenario was not known years in advance, the government failed spectacularly, especially one that spends a trillion dollars per year on "defense"
No. This calls on everyone to make their own. Lots of video tutorials, and some examples are dead simple (two rubber bands and a paper towel, if you have to).
> (two rubber bands and a paper towel, if you have to).
Two paper towels and a tissue paper actually.
The different materials lead to better filtration and absorption. The theory is to absorb the microscopic moisture that has COVID19 on it.
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I think the "cut t-shirt" design is easiest. With a bit of sewing effort, you can make it 3-ply or 5-ply for additional protection. Try to get the grains to go in different directions.
It's interesting to look at the numbers for this. Google says there are 2.86 million registered nurses in the US. Lets add in doctors and other healthcare workers and say there are 10 million workers (probably more). 3M is making 100 million masks a month. That's only enough for each of them to get 10 a month. They probably go through that in half a shift since they have to change per patient.
Yes! China is cranking out 300,000,000 surgical masks per day and they're available on Ali Express. I have 100 in my hand made on 3/15 - most are going to the local hospital today. Have 200 on order and should arrive in five days.
I just ordered a couple washable ones from Etsy.
The video convinced me I shouldn't keep waiting for them to be back in stock at the store.
No.
This guy does an amazing piece on masks, gloves and sanitation. Also explains how to remove masks properly. https://www.youtube.com/watch?v=kLWBG_fbJR0&t=1217s
If you're not infected, a mask doesn't cover your eyes, so you can still get the virus in the same way you would by breathing near an infected person. And you're probably going to think you're safe, and then touch an infected surface, and then touch your face/eyes. Congrats, your dinky non-N95 mask was pointless.
If you are infected, just use any mask. Your breath still escapes from an N95 mask's corners, spreading the virus nearby, and probably onto your hands. Sure, it won't projectile-travel as far, but it's still spilling out onto nearby surfaces/people.
In Asia, face masks have been trendy ever since the avian flu. But tons of studies showed that this had no significant effect on reducing people getting sick, because eyes, and touching face. The masks are just a psychological thing at this point.
So how do you know if you are infected?
Ever since I saw a some officials wearing safety glasses I've been wondering: is eye protection effective against coronavirus (or were these people paranoid about getting sneezed in the eyes)?
From a recent episode of This Week in Virology[1]:
"Historically, in a lot of health care settings there was limited attention [to eye protection], and part of droplet protection, part of being protected when someone coughs or sneezes is protecting your eyes as well. Actually, going in to this I was pretty heavy on re-education at one of the hospitals about: if someone's on droplet, you gotta protect your eyes. Because influenza, you get that in your eyes you can get infected. SARS-CoV-2, you get that in your eyes you can end up with COVID-19. So eye protection is important as well."
[1] - http://www.microbe.tv/twiv/twiv-593/ at about 1 hour and 58 minutes in to the program
The eyes are a possible entry point for droplet transmission, so yes as it being part of other protections (mask, washing hands). Some have used/made face shields.
Apple should make FaceID better at identifying faces through masks so people aren’t tempted to remove their mask to use contactless payment.
Considering humans often use masks like these to conceal their identity, it's probably going to be difficult if not impossible to make it work reliably. For those using an Apple Watch it will be easier to pay that way.
Note: hn has been flagging mask discussions
See https://news.ycombinator.com/item?id=22733249
And https://news.ycombinator.com/item?id=22706216
I'm not too frustrated about this because there's a lot of confusion on mask usage, people buying masks that doctors need, etc.
WHO still recommend not wearing mask, unless you are infected or caring for an infected person.
Yeah, it's a stain on scientific institutions that the WHO and CDC are peddling unscientific nonsense. Makes me sad.
There's now a report that the CDC may start encouraging people to cover their faces in public.
https://thehill.com/homenews/administration/490308-cdc-may-u...
They do not recommend wearing a mask, which is different from recommending not to wear a mask.
Edit: Here's the WHO's stance on wearing masks: https://www.who.int/emergencies/diseases/novel-coronavirus-2...
This is an unfortunate side effect of how it's worded in many English articles. And like a game of telephone, the precision is lost in communication in social settings/media and people are telling each other to not wear masks (at least that's what I'm seeing)
Thanks for clarifying, I had wrote it wrongly.
If symptoms don't show up for days, how do you know you're not infected?
Is there any real evidence that masks provide any value for healthy people (excluding health care workers)? All I've seen are anecdotes from internet armchair experts.
The parent link has a link to a list of papers[1] that answer this question in the affirmative:
For example, "Professional and Home-Made Face Masks Reduce Exposure to Respiratory Infections among the General Population" [2]
It's also worth noting that many people with COVID-19 are asymptomatic, so wearing a mask, even a homemade one, could reduce the spread to other healthy people.
[1] https://docs.google.com/document/d/1HLrm0pqBN_5bdyysOeoOBX4p...
Scientific papers studying and summarizing the utility of masks, from the article: https://docs.google.com/document/d/1HLrm0pqBN_5bdyysOeoOBX4p...
I think part of the issue in this case is that no one knows if they are "healthy." You could be transmitting the disease while still asymptomatic yourself.
"Most cases of severe acute respiratory syndrome (SARS) have occurred in close contacts of SARS patients. However, in Beijing, a large proportion of SARS cases occurred in persons without such contact. We conducted a case-control study in Beijing that compared exposures of 94 unlinked, probable SARS patients with those of 281 community-based controls matched for age group and sex. Case-patients were more likely than controls to have chronic medical conditions or to have visited fever clinics (clinics at which possible SARS patients were separated from other patients), eaten outside the home, or taken taxis frequently. The use of masks was strongly protective. Among 31 case-patients for whom convalescent-phase (>21 days) sera were available, 26% had immunoglobulin G to SARS-associated coronavirus. Our finding that clinical SARS was associated with visits to fever clinics supports Beijing's strategy of closing clinics with poor infection-control measures. Our finding that mask use lowered the risk for disease supports the community's use of this strategy."
Yes! The page links to this document, which gives what appears to be a fairly comprehensive review of the literature: https://docs.google.com/document/u/0/d/1HLrm0pqBN_5bdyysOeoO...
Yes. They provide value by protecting others from you. You don't know if you're "healthy" because even asymptomatic or pre-symptomatic cases are contagious. You wear the mask to protect others, not yourself. Others wear masks to protect you.
I don't see what a persons profession has to do with whether or not a mask protects against a virus or not? The difference is exposure not efficacy of the tool.
It's all linked on the website: https://tiny.cc/maskswork