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UMD study: N95 masks nearly perfect at blocking Covid
- ptliddle 2y agoThe title is misleading. The study found duckbill N95 masks "blocked 99% of large virus particles and 98% of small ones". This is important because the issue with masks was always to do with fit and longterm ware habits, not that N95 material was ineffective at blocking viral particles.
- wordofx 2y agoThe main issue is people think masks prevent you getting sick. Rather they are designed to prevent you making others sick.
- hollerith 2y agoNot true of masks that comform to NIOSH's N95 specification such as the ones routinely worn in hospitals to provide care to COVID patients and which are readily available for $2 per mask without a prescription.
- monksy 2y agoThe public health initive was a collective one that tried to incentivize widespread usage as opposed as personal protective equipment (as that good masks are). Unfortunately the initiave was a (many)day(s) late, and $1(00000000) short. Other nations [that used a higher standard of mask] did not have nearly as bad of numbers as the US had under the mask usage policies/regulations.
- leptons 2y ago>Rather they are designed to prevent you making others sick. Except N95 masks weren't designed for that at all. N95s and better masks have been worn for decades to protect the wearer from all kinds of airborne problems, from dust to virus particles. They have proven quite effective at that task. But maybe you think all those workers in the Ebola ward are just wearing masks as a fashion statement? Masks do prevent the wearer from getting sick, far more than wearing no mask at all. Is it 100% protection? No, but nobody should be complaining about that. I'll take 95% protection or even 50% protection over no protection at all.
- Animats 2y agoRight. The classic "3M 8210 Plus N95 Performance Sanding And Fiberglass Disposable Respirator (20-Pack)" sells for about $1 in boxes of 20 at Home Depot, Lowes, etc. That's a good mask. Wearing one properly isn't rocket science, but is non-obvious. There's an instruction sheet in the box. You put it on, and then, using your palms, squeeze the part over your nose, which bends the mask and the metal stiffener. Check that you got it right by exhaling, then take a deep breath and feel the edges of the mask pushing against your face. If you don't feel the mask pushing, you did it wrong. Training video from OSHA: [1] There's a serial number on the box. If you type it into 3M's web site, they will tell you if it's valid and if anyone ever queried that number before. This protects against counterfeit masks. Once you get an OK from the site, initial the box, so you don't ask the site again. There's also a test kit you can buy, with a little bottle of a strong-smelling substance. If you can smell it with the mask on, you did it wrong. The way these things work is subtle. There's an inner layer that's an electret, with a permanent electric field. Particles smaller than the mask mesh are caught and held by the electric charge. That's what makes these work against really small particles. They're actually more effective as particles get smaller. The "95%" is for the particle size for which they are least effective. I've been wearing those since the beginning of COVID and never got COVID. I had a supply of those, because I used to use a water jet cutter at TechShop. This is all ordinary personal protective equipment, familiar to anyone who works around moderately dangerous industrial processes. [1] https://youtu.be/pGXiUyAoEd8?t=149 https://youtu.be/pGXiUyAoEd8?t=149
- 2y ago
- jvanderbot 2y agoHonest question: Why do we need it to block _viruses_. Surely the virus isn't flying around with wings. Doesn't it travel on water droplets? Doesn't the mask do most of its good work by keeping water droplets in (or out)?
- thsksbd 2y agoDepends on the virus. Not all need a droplet
- jvanderbot 2y agoWell aren't we talking about COVID here?
- thsksbd 2y agoSure, but check your sentence's grammar; it implies you're asking as a general rule of biology. As to COVID, dunno.
- bena 2y agoIIRC Covid is airborne so it doesn't need to travel on droplets. But feel free to double-check that one. Everything surrounding Covid is so tied to politics and identity, it's easy to get things mixed up between actual studies that have actually demonstrated a thing and people just spouting off whatever just came out of their assholes. In other words, I believe I read an article on how we know now that Covid doesn't need droplets to transmit, but it honestly could have just been someone saying that there was an article claiming that and I've just conflated being told there's an article with actually reading the thing.
- ceejayoz 2y agoThis varies from virus to virus; some generate droplets, some generate smaller particles ("aerosols" / airbone transmission). Measles is so infectious because it travels in smaller particles that linger in the air longer.
- ajross 2y ago> the issue with masks was always No it wasn't. It was "I don't want to wear one"[1]. And the frame of the argument was fit to the desire. It was true then and remains true now that the single best protection for You Personally (absent isolation) is to put on and wear a mask. That remains true whether or not the "fit" is ideal or on the state of "longterm wear habits" of the rest of society. [1] Though eventually the politically reframed corrolary of "You can't make me wear one" got more play.
- delecti 2y ago> To reflect the general public's use of masks, study volunteers were not fit-tested for their masks or trained how to properly wear them I think your cynicism is not supported by the study.
- ptliddle 2y agoRead further down in the study. It discusses exactly what i'm referring to in that air was pushed out the sides with KN95 masks and one of the reasons cloth masks performed better then KN95s was a better fit.
- mikehodgson 2y agoThe title is still not misleading. You're conflating the results from two different masks. Both N95 and KN95 were tested.
- ptliddle 2y agoAnd it showed that KN95s are NOT perfect at blocking COVID. This is why the general public now distrust scientists, because the media presents it to them inaccurately and tells them results the study never found. Science is about precision. The study did not find all N95s where nearly perfect at blocking covid, that's flat out inaccurate. Also let's be really precise here. I'm not conflating anything and i think you don't realize you are. 1) KN95 and N95 use similar filter materials they both have to filter 95% of particles down to 3 microns, the difference is to do with certification N95 is a US certification and KN95 is a Chinese certification. So the material is essentially the same between them. The fits tend to be different. 2) What i'm getting at is the title said all N95s, that's not what the study found, it found that a specific fit style "duckbill" was "Nearly Perfect at Blocking COVID" the non duckbills did not. So to be accurate what the study did NOT find which the title suggests is that all US certified masks that filter 95% of particles down to 3 microns were nearly perfect at blocking COVID.
- deleted 2y ago[deleted]
- lesuorac 2y agoDid you read the article? The issue of fit was addressed. > (To reflect the general public's use of masks, study volunteers were not fit-tested for their masks or trained how to properly wear them.)
- ptliddle 2y agoRead further down in the study. It discusses exactly what i'm referring to. The title says "N95 Masks Nearly Perfect at Blocking COVID" that's not what the study found. It found that duckbill N95s were nearly perfect at blocking COVID.
- legitster 2y agoAnd an important clarification: even if a virus particle is too small to make it through the mask - it is always riding some sort of host to transmit - water partical or something that help it transmit through the air. Everything was moot though if you ripped off the mask and wiped your hands all over your face when you were done.
- ceejayoz 2y ago> Everything was moot though if you ripped off the mask and wiped your hands all over your face when you were done. No, probably not. There's very little evidence of transmission via surface contact; you have to breathe a significant amount into the nose/lungs, and the surgical and N95 masks are additionally statically charged to keep viral particles stuck to them; this is how they block viruses much smaller than their own pores. (https://www.wired.com/story/the-physics-of-the-n95-face-mask/ https://www.wired.com/story/the-physics-of-the-n95-face-mask...)
- legitster 2y agoI think the thing with the N95 masks is they could stay moist all day from your breath's condensation. Covid was very dependent on moisture to spread, and much of the evidence about surface contact implied that the surface was dry or dried out between contacts. Though to your point it was probably a lower risk than what might have been implied.
- wordofx 2y ago[flagged]
- reedciccio 2y agoDo you mean that chin diapers don't work? https://m.youtube.com/watch?v=s8vwqRHr9a4 https://m.youtube.com/watch?v=s8vwqRHr9a4
- 5667hhjjj 2y ago[flagged]
- skyyler 2y agoWe force you to wear a seat belt... Calm down, killer.
- 5667hhjjj 2y ago[flagged]
- llamaimperative 2y agoWhat about "forcing" you not to walk around with your genitals out? I presume you're okay with forcing other people to cover their genitals, right?
- leptons 2y agolol, your account was created 11 minutes ago for the purpose of rage commenting.
- thsksbd 2y agoAs exercise in power; after all, motorcycles still exist. Sure seat belts save lives. Thats why I wear one. But it's also true that many people get off telling other how to do things.
- nameless912 2y ago
- ajross 2y agoSo weird that the state of our discourse, even four years post-pandemic, is still stuck on "do masks reduce disease transmission", something that (1) has been paradigmatically settled science* since the dawn of the germ theory of disease, (2) has never been seriously challenged and (3) remains true every time (as here) it's been re-studied. Yet... * Not quite the same thing as "true". Very rarely paradigms are wrong. But they aren't here, and... I mean duh.
- n8henrie 2y agoI'm baffled that this is your take. I'm relieved to see some positive evidence, since the Cochrane reviews on the topic keep concluding "little to no benefit" for either surgical masks or N95s.
- zdw 2y agoAnyone have a link to the actual paper? Compare this with: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006207.pub6/full https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD... which states "The pooled results of RCTs did not show a clear reduction in respiratory viral infection with the use of medical/surgical masks." Anyone have a good insight on which has a more accurate methodology? FWIW, I've been of the opinion that masks help (obviously they do something), so I'm inclined to doubt the link I gave above.
- cinntaile 2y agoThey're not the same type of masks. N95 is a higher class than surgical masks.
- ceejayoz 2y ago"medical/surgical/procedure masks" are the blue/yellow loosely fitting ones; non-N95. https://en.wikipedia.org/wiki/Surgical_mask https://en.wikipedia.org/wiki/Surgical_mask
- lesuorac 2y agoAfaik, this is an apples-to-oranges type thing. Cochrane's analysis is that they can't say if masks are effective or not. It's not evidence of harm or helpfulness. A similar way to think about this is if I show you a coin and ask you if it's weighted? You don't have enough information to make a determination (perhaps if I flip it a bunch of times you can claim one way but that's not part of the question/data). I didn't run any statistical analysis on their tables but given that their "Viral respiratory illness ‐ influenza/COVID‐like illness" for No Masks is 160/1000 while "Viral respiratory illness ‐ influenza‐like illness" for Masks is 50/1000 I'm guessing masks do have an effect but the amount of samples in their data is not enough to demonstrate it. Where the oranges come from is the UMD paper is studying how many viruses appear in a plague doctor's mask [1] which is obviously different than how many individuals get sick (apples). [1]: https://sph.umd.edu/sites/default/files/styles/optimized/public/2020-12/PHAB-Lab.jpg?itok=flPZtUjK https://sph.umd.edu/sites/default/files/styles/optimized/pub...
- cameldrv 2y agoActual paper: https://www.sciencedirect.com/science/article/pii/S2352396424001920 https://www.sciencedirect.com/science/article/pii/S235239642...
- legitster 2y ago> Cloth masks also outperformed both KN95 and surgical masks. Milton theorizes that cloth variants were the second-most effective masks tested because of greater coverage that wraps around the face and gives a better seal than either KN95 or surgical masks. Flow resistance is also lower, allowing breath to pass through rather than around the filter. I'm always baffled by the people who went around arguing masks did nothing. They don't seem to have any problem accepting that a sneeze guard at a salad bar does something, or that a surgeon should put something on their face to prevent them from coughing into your open body cavity. We can argue all day about specific masks under specific settings, or when it is worth it to bother, but "putting something in front of your face prevents you from breathing out particles" is in the category of "things that are pretty f&%*ing obvious".
- dboreham 2y agoAlso something that medical practitioners have been doing on a daily basis for 100+ years.
- candiddevmike 2y agoTrump didn't want to wear masks because it smudged his bronzer: https://newrepublic.com/post/175706/cassidy-hutchinson-trump-masks-covid-bronzer-makeup https://newrepublic.com/post/175706/cassidy-hutchinson-trump... It was never about science, it was about convenience.
- hartator 2y agoIsn’t the sole goal of engineering to use science and make nature convenient for humans?
- legitster 2y ago> It was never about science, it was about convenience. There was an inverse problem coming from the other side though. There was also a large and vocal group who argued that the masks did nothing as a way to create unnecessary anxiety and force unnecessarily inconvenient lockdown restrictions - like banning people with "inferior" masks.
- 2y ago
- sschueller 2y agoIs this when the infected is wearing it or someone trying to protect from getting infected?
- delecti 2y agoThe former. From TFA: > “Data from our study suggests that a mildly symptomatic person with COVID-19 who is not wearing a mask exhales a little over two infectious doses per hour says first author Jianyu Lai, a postdoctoral researcher at the PHAB Lab. “But when wearing an N95 mask, the risk goes down exponentially.”
- grumple 2y agoLink to study: https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(24)00192-0/fulltext https://www.thelancet.com/journals/ebiom/article/PIIS2352-39... More surprising is that cloth masks were better than KN95s! That's pretty cool. Sample size was quite small though (only 8 cloth mask participants) and the study in general had a pretty small sample size (surely it couldn't have been difficult to find covid-positive individuals?).
- zactato 2y agoI believe that the conflict over masks stemmed from a fundamental difference in perspective. Masks work great at blocking transmissions even if the fit is bad, much like covering your mouse when you sneeze. Masks CAN work great at blocking absorption if fitted properly, but thats hard to do correctly If you are a fundamentally selfish person you only care about whether masks prevent YOU from getting COVID, you don't care about spreading it. If you are non-selfish, then you probably care about both yourself and the broader community well being and are not only concerned about catching covid yourself, but also spreading covid to other people. I think its hard for these two groups to interact because there's not much common ground. I would argue that if you only care about your own risk of catching COVID and don't have training on N95 masks, then the argument that masks aren't worth the hassle is probably right.
- HappySweeney 2y agoTFA directly refutes the "CAN work great at blocking absorption" claim. It says N95's work great, even when not properly fit tested.
- cameldrv 2y agoYou don't really need "training" to effectively use an N95 mask. If you just read the package directions and do a pressure check as directed, and it passes, you're going to be getting very good protection.
- deleted 2y ago[deleted]
- init2null 2y agoI dearly love my N95 duck bills and always wear them while flying. I'm not really worried about COVID now, but why would I want to risk getting from anything? A cold could ruin my trip. A few hours of discomfort, but I'm uncomfortable anyway. I was surprised that the airlines were repeatedly trying to get people to remove their masks one time I flew on the tail end of the epidemic. Will they bring me chicken soup if I get sick?
- beej71 2y agoSame. I wear masks on the outbound flight. If I'm dropping thousands on a vacation, I want to be healthy for it. I'll take my chances on the return flight.
- readthenotes1 2y agoI rarely saw people wearing masks over both nose and mouth. Favorite memory is the guy in the metro who took the mask off his mouth to sneeze (and no, it didn't begin by covering his nose)
- ceejayoz 2y agoDuring the early days, I think a good amount of those were "I'm required to wear one but they can't make me wear it properly". I'm most baffled by the people I see today with a mask on but around their chin. They haven't been required for years, so I presume it's being particularly COVID-conscious (as someone on an immune suppressant, I still wear N95s in public)... but if you're that conscious you'd think you'd wear it right.
- archagon 2y agoAnecdotally, I’ve been wearing N95 indoors (outside the home) since the pandemic started and haven’t gotten sick yet, even when friends got sick from being in the same venue as me (e.g. office, airplane).
- dent9876543 2y agoThis is exactly what the guidance should have been about, right from the start. Basically, if you are in a vulnerable group, wear a mask around others. Make it a good mask. Fit it well. Especially if the group is known to be 'risky' or large. And for those extremely vulnerable groups, wear a mask around them as a courtesy. But it got warped into 'wear a mask around everyone at all times'. And that just didn't make sense to a lot of people.
- leptons 2y ago>'wear a mask around everyone at all times'. That was never the message. Inside your own home with your own family? No, nobody suggested that anyone must wear a mask in that situation. Out in public, indoors, during high transmission times? Yes, absolutely wear a mask in that situation, every single time. This is common sense stuff, but people fail at common sense quite often these days.
- dent9876543 2y agoBut isn’t it also common sense that, if it’s already in high transmission then you wearing your mask isn’t going to budge the dial. Thing is, at those times, responsibility needs to shift back to the individual to take care of themselves. Most people judged they didn’t need substantial protection (else they’d have worn better masks, well fitted, always). We sometimes look at human behaviour and find it superficially irrational. But this is an example where rationality simply doesn’t conform to what some would wish it to. It’s still rational. And I would also argue it is common sense.
- leptons 2y ago
- musha68k 2y agoWhy is this flagged?
- acdha 2y agoThe right-wing spent a couple of years demonizing mask policies, and the major talking point was that masks didn’t work. You don’t need that many people to flag-kill a story and there’s far more than that number who will go to the grave not admitting they were wrong.
- musha68k 2y agoIn that case HN has finally strayed from its "hacker ethos" and objectively wanting to find out about any system over time at least; truth. Eventually right (even) in online discussions? No more. OK. Maybe I've been thinking about this forum too highly for too long already? Probably. Could this be another potential signal for the trend of the attention economy's created culture taking over in this turbulent and in many ways regressive global state? If so, this is starting to feel "on rails". Scary.
- bena 2y agoIt's been veering that way for years. Moderation has some huge blind spots that's allowed a corrosive element to build a core in the community. But that's the fate of all social networks. We've yet to figure out how to scale social interaction. When a network gets large enough to grant relative anonymity to people, the worst comes out.
- acdha 2y agoI think of it as a consequence of the field expanding and becoming a high-income profession: with more people in total, regression to the mean is going to inevitably show up and the hyper-focus on capitalism bleeds through in many places. Mask mandates were proclaimed to be bad for business so a certain level of opposition is largely baked in.