It's very irritating because people don't understand the concept of defense in depth. Are surgical masks going to give you total protection? Of course not, but as you say they provide SOME benefit. Saying "masks don't work because they don't fully stop the virus and users misuse them" is basically equivalent to saying "code review is a waste of time because it won't catch every bug and because devs don't do it correctly". The solution isn't stop doing code review, it's to teach people how to do it and to understand it's limitations.
> Are surgical masks going to give you total protection? Of course not, but as you say they provide SOME benefit. Saying "masks don't work because they don't fully stop the virus and users misuse them"
Surgical masks aren't about protecting the wearer from everyone else, they're about protecting everyone else from the wearer [1]. They may provide the wearer some protection, but that's not really the point.
The emphasis in the rhetoric about masks needs to change. It should not be about individualist self-protection, but about doing your part to protect the community. I think they should be recommended for that reason [2].
[1] Respirators are devices for protecting the wearer, and the N95 type has been much discussed. Everyone should learn the difference to de-confuse the general conversation in this topic:
[2] If there's enough supply. It seems like surgical masks are getting drafted into the role of PPE for medical personnel (which they're poorly suited to) due to the N95 shortage. It's unfortunate that the US hasn't developed a culture where you wear a mask to protect others from your illnesses, so they're not widely available outside of healthcare settings.
>Surgical masks aren't about protecting the wearer from everyone else, they're about protecting everyone else from the wearer [1]. They may provide the wearer some protection, but that's not really the point.
I think you're confusing the normal use for these masks with what they are actually capable of doing. Yes, in a surgical setting the masks are worn primarily to protect the patient from the surgeon, but the masks do work both ways. Here's a citation from an infectious disease specialist:
>“Yes, a surgical mask can help prevent the flu,” Sherif Mossad, MD, an infectious disease specialist at the Cleveland Clinic, tells Health. “Flu is carried in air droplets, so a mask would mechanically prevent the flu virus from reaching other people.” It would work both ways, says Dr. Mossad, preventing transmission of the flu virus to others and for keeping a mask-wearer from picking up an infection.
>> Surgical masks aren't about protecting the wearer from everyone else, they're about protecting everyone else from the wearer [1]. They may provide the wearer some protection, but that's not really the point.
> I think you're confusing the normal use for these masks with what they are actually capable of doing. Yes, in a surgical setting the masks are worn primarily to protect the patient from the surgeon, but the masks do work both ways. Here's a citation:
I wasn't confused. That's why I said they may provide the wearer some protection. The 3M YouTube video I linked even quantifies this, by measuring and comparing leakage between a surgical mask and an N95 respirator.
But that's not the point. Don't wear a mask to protect yourself, wear a mask to protect others.
Yes an N95 mask provides more protection than a surgical mask. That's completely different from whether either mask protects the wearer. Both masks absolutely protect the wearer from infection. I'm sure you understand that, but the way you are wording things makes this unclear.
If you have a mask shortage and there is one mask left in the country, is it better for the society for the sick person to wear it or for healthy person to wear it?
I simply will not stand to be "managed" or lied to. The masks protect the wearer. That is a simple fact. Anyone who states/implies otherwise is either ignorant or a liar.
Now we have the separate issue of the fact that there is a critical supply shortage. In such a scenario I'm more than happy to oblige in managing systemic risk by allocating all the masks to healthcare workers, the critically vulnerable, etc. But don't lie to me along the way.
He is not lying to you. That’s disingenuous. The OP is stating that the very little protection you get by wearing a mask does not warrant you horsing it. Masks should be used by sick people to
Maximize their proficiency. I’m surprised to read such comments in the HN community which is supposed to be focused on engineering and optimization within a set of constraints.
> Surgical masks aren't about protecting the wearer from everyone else, they're about protecting everyone else from the wearer [1]. They may provide the wearer some protection, but that's not really the point.
Normal people using surgical masks in public are definitely also for protecting the wearer, and do offer protection.
"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."
I know what their stated purpose is, but it is true that wearing a mask protects the wearer as well to a degree. Stating that it doesn't (as many in the media / CDC / politicians have said) is factually incorrect. If they want to say that masks need to be preserved for healthcare workers or sick people, then they should say so and I would agree, but when they start bullshitting to try to trick people into the behavior that they want then it completely undermines their credibility. People then start asking things like "is it actually true that we need to socially distance or is that a lie as well?" The number one thing you should not do during times of crisis is start lying.
For example, I don't trust the WHO much anymore because they lied and said that closing China's borders would not stop the spread of corona behind pressure from the Chinese government.
What's more frustrating is the exact same logic applies to "social distancing." Social distancing will not completely stop people from getting sick. It'll just slow the spread. So, according to the CDC, an imperfect solution for quarantine is totally fine, but when it comes to masks, only n95 or better are worth pursuing.
It's quite likely that in all the scenarios a mask may have a useful effect, N95 or better is the only time it works.
For medical professionals in close contact with patients and dealing with airborne-protocol pathogens (which is what a droplet-mediated pathogens like SARS2 becomes classed as once patients are coughing and being intubated) then a bad mask is quite probably worse then no mask (this has precedent: ineffective masks obstruct breathing, which makes you take deeper breaths and draw more particles in deeper in your lungs - it's a big problem when dealing with fine dusts in construction).
> It’s quite likely that in all the scenarios a mask may have a useful effect, N95 or better is the only time it works.
You’re saying you think anything less than an N95 has 0 effectiveness. Why do you believe this is likely? Are you aware of the data that says otherwise?
“As worn by health care personnel in this trial, use of N95 respirators, compared with medical masks, in the outpatient setting resulted in no significant difference in the rates of laboratory-confirmed influenza.”
To be clear, this trail was for outpatient care — not necessarily applicable to shoving tubes down throats, but probably applicable to people walking down the street.
The data from the Davies paper is not very convincing. The home made solutions offered significantly less protection and and had major problems with fit. Even their conclusions were — it’s better than nothing, but not a proper substitute.
> However, these masks would provide the wearers little protection from microorgan- isms from others persons who are infected with respiratory diseases. As a result, we would not recommend the use of homemade face masks as a method of reducing transmission of infection from aerosols.
Better than nothing is the whole point. N95 masks are not a substitute for avoiding exposure in the first place, but nobody’s saying N95 masks are ineffective because of that fact.
The recommendation here is assuming you have access to something better. If you have no access to something better, a homemade mask is better than no mask at all, until you can get something better. As others have pointed out here, it’s rather odd to suggest we should scoff at this imperfect solution, when there are no perfect solutions short of 100% full and complete quarantine, which is completely unrealistic.
It's highly likely that even basic surgical masks have some impact. A fit-tested N95 is the gold standard, but the widespread use of surgical masks in Asia during the SARS epidemic does seem to have had an impact.
Agree & upvoted; this needs to be better understood. Especially noteworthy is the section you linked to is written for health-care workers, and they’re confirming that a homemade mask is better than nothing (while also recommending the homemade mask dead last.)
Unfortuately, the CDC really is giving out conflicting guidance here. For example, higher up in the section for lay-people is this: “You do not need to wear a facemask unless you are caring for someone who is sick (and they are not able to wear a facemask). Facemasks may be in short supply and they should be saved for caregivers.” https://www.cdc.gov/coronavirus/2019-ncov/prepare/prevention... (In “How to Prepare | Protect Yourself”)
I don't see a contradiction. The CDC is trying to maximize public health benefit. They recommend stronger protection for people with more exposure to higher levels of the virus. Coincidentally, the people with higher levels of exposure also happen to be health care workers, who need the best available protection to save lives
If you are not exposed to high levels and are not required to put yourself at risk to care for patients, you are at low risk. You can protect yourself with milder measures like social distancing and face protection that is not as effective but not in such short supply
Maybe I misread your intent. I thought you were mostly pointing out the section titled “When No Facemasks Are Available, Options Include”, which would mean we’re talking about something that is not in short supply. I thought you were pointing out that, among other things, the CDC is saying that home-made masks are better than nothing, even for health care professionals, and even if it’s a last resort.
I mean I agree, of course, that they’re trying to maximize public health benefit, I just don’t think the guidance is at all clear to the public. The idea that anything less than N95 is useless is pervasive, you can see it right here on HN. My parents and co-workers believe it because it’s been reported in the mass media in the last weeks: “the CDC said masks don’t protect you!”.
For people who need to work or shop in public places, any kind of masks at all might well be statistically significant alternatives for people who are unable to practice social distancing. China seems to be doing it effectively right now; people are required to wear masks to go to work. They’re not telling the public to avoid masks because doctors need them, they’re telling the public not to leave the house and not to enter a work building without something over your face. It seems like the CDC is saying the opposite, you should not wear a mask unless you’re a doctor. If a bandana is even 50% or 30% or even 5% effective, and they want to maximize public health benefit, why aren’t they recommending people start with what they have at home for times when public exposure is necessary? Seems like that would both increase public health and deflect demand for surgical masks & N95 masks at the same time, no?
That's not necessary so. While "not doing social distancing right" will not increase your risk compared to not trying, with masks it's not so clear cut: You have to touch your face to put them on and take them off, and people might touch their face more often to adjust them etc. That increases the risk, at least if you wear them to protect yourself. And people might take greater risks because they feel safe. If this is not counterbalanced by the risk reduction through wearing a mask, it's a problem.
Additionally, if there is a mask shortage, it might increase the risk indirectly, even for those who don't want to spread it.
If there are two "mental tools" I wish we could teach every person, they are exponential growth and statistical thinking. Neither is intuitive, but they would help people understand this whole situation (and many others) a lot better.
My high school math teacher introduced exponential growth by asking the class if we'd take $1M now or $0.01 doubled daily for a month. We, as most people do, wanted the $1M, but the penny turns into more than $5M.
Had to explain this to someone yesterday. They literally wouldn't believe me until I screenshotted an Excel spreadsheet of the daily doublings, despite a finance degree.
I think that's exactly the issue. People can't picture it. You can show them a curve on a graph, but that doesn't translate for people without a mathematical/scientific background into "a shitload of people will get ill very quickly." Our brains seem not to be very well wired to make the connection between mathematical abstractions and reality, and aside from the minority of people who seem to just "get it," people don't understand without a good explanation from a very good teacher.
We technology people don't just inherently "get it", but rather have experience traveling up and down in powers of two for things that are meaningful to us. A month has 30 days - that's easily recognizable as a giga (2^10 ~= 10^3). And a billion isn't even that large to us.
Very true. But it doesn't stop there. One of my pet peeves is that people who believe they understand exponential growth will extrapolate too far in the future. More often than not, processes working against the exponential growth, negligible small in the beginning, will grow even faster and will reduce the grow rate, even without external intervention.
In the example of COVID, it's the chance of interaction of an infected with an uninfected, even without social distancing, just because so many people will be infected, or dead. This effect is completely negligible in the beginning, but dominates in the end. (Of course, all the people modelling the epidemic have this effect in.)
I like to think that every contact outside increases risks. And conversely, to keep my sanity, that every prevented contact helps reduce the risk a little bit
"It's a great pleasure to be here, and to have a chance just to share with you some very simple ideas about the problems we're facing. Some of these problems are local, some are national, some are global.
They're all tied together. They're tied together by arithmetic, and the arithmetic isn't very difficult. What I hope to do is, I hope to be able to convince you that the greatest shortcoming of the human race is our inability to understand the exponential function."
Most people I try to explain the current problems are really not able to understand. I explain that the spread is exponential, and that the problem is that is grows so fast. I say look at the graph from China, look at the graph from Italy.
They answer "ah, the Chinese maybe hid some numbers."
I say, it just doesn't matter, only the shape of the curve matters, and it repeats in every land. Even if the Chinese hid half of the cases, that difference disappears in only three-four days in our locations, where it grows so fast, as it grew in China before they did their measures, much harder than ours.
They don't understand still. They think only "80000 in China is more than "50000 in Italy" and it stops there. That Italy will get from 50K to 100K in four days, that's what they don't understand until they'd see it happened, but it would still, sadly, not convince them in anything.
Whereas, not only it's just the shape of the curve that matters, we know exactly why the spread is exponential, and what has to be done to change the shape: manage to stop the people who have it to transmit the virus to the rest of the population. It's "just" people who spread it -- the virus is not a bacteria, it doesn't live or multiply by itself, it needs a host which will replicate it, and the only host spreading it among the humans is human. There's nothing else that we know to work than that.
The major danger is that 4 from 5 carriers of the virus won't feel so bad to think that they should really stay at home. Most of the carriers aren't aware what they do. They all have their lives where what they do at the moment is "urgent" and "must be done." As soon as the droplets they produce enter the lungs of other people, the virus is spread. The droplets are tiny enough to be normally invisible to us, of course.
It doesn't help at all that the most of the highest politicians, across many different countries, downplayed the seriousness of the situation for a long time. Even less that the scientific ignorance was promoted as a virtue for even longer times.
BUT. Not meeting someone is 100% protection at this poin we need 100% protection for everyone not 100% needed to keep the lights on and people fed.
So yes once you've removed all non essential contact masks add another layer. But people are fairly stupid on average and need simple messages right now.
