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piL
Sep 20, 2007
(__|\\\\)

Taco Defender

Bleeding over from CE thread so masks can be discussed.

I decided to collect some evidence, please discuss masks here but try to do so in a sciency way. There's a huge tension here. Proving things is hard. The rigor of evidence expected of science is much higher than the rigor used in normal decision making. It must be, or you'd never leave the house. My objectives here areas follows:

  • To steer the discussion towards science-backed arguments .
  • Failing that, to categorize the rigor of the ideas discussed--what is probably, maybe, or unsupported?
  • To quarantine :dadjoke: masking arguments out of the CE thread.

To these objectives, please make references clear: is this a peer-reviewed reference? Is this an academic source, or a popular source? Editorial, journalism, or a study? I don't make the rules, so I won't tell you you can or can't post, but if you're going to argue against mask-use in any way, you should be showing up with evidence, preferably backed by clinical trial, or you may be risking harm and that might not constitute being excellent to one another.

Not sure how to read a paper? Read this: https://www.science.org/content/article/how-seriously-read-scientific-paper. If you have better advice on this, share it.
Not sure if the stats match up? Ask! I'm no expert, but exploring methods will make us stronger at discerning evidence!

OP recommendations welcome!

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piL
Sep 20, 2007
(__|\\\\)

Taco Defender

I read a few articles. Where I stand right now: based on Abaluck et al, I feel pretty confident that encouraging any mask use is good, that surgical masks are better than cloth masks. My intuition suggests N-95 masks will likely be as good or better than surgical masks against COVID-19, but evidencing that effect among casual non-professional users is a difficult task. N-95 masks are probably not worse than surgical masks, but I haven't been presented evidence that they're better. More specific thoughts below:




The Impact of Community Masking on COVID-19: A Cluster-Randomized Trial in Bangladesh
Authors: Jason Abaluck, Laura H. Kwong, Ashley Styczynski, Ashraful Haque, Md Alamgir Kabir, Ellen Bates-Jefferys, Emily Crawford, Jade Benjamin-Chung, Salim Benhachmi, Shabib Raihan, Shadman Rahman, Neeti Zaman, Stephen Luby, Mushfiq Mobarak, Mohammad Ashraful Haque, Md Alamgir Kabir, Ellen Bates-Jefferys, Shabib Raihan, Shadman Rahman, Neeti Zaman
Publishing date: 1 Sep 2021
Publisher: Innovations for Poverty-Action (study)
Peer-reviewed?: Unknown
Where to access: https://www.poverty-action.org/publication/impact-community-masking-covid-19-cluster-randomized-trial-bangladesh


  • Abstract: cluster-randomized trial to measure the effect of community-level mask distribution and promotion on symptomatic SARS-CoV-2 infections in rural Bangladesh from November 2020 to April 2021 (N = 600 villages, N = 342,183 adults)
  • Abstract: Study shows increase in mask-wearing by through the studied distribution and promotion systems.
  • Abstract: Study showed differences of "sympotomatic seroprevalence," especially with use of "surgical masks" Specifics will be further explored below.
  • Introduction: "The World Health Organization declined to recommend mask adoption until June 2020, citing the lack of evidence from community-based randomized-controlled trials, as well as concerns that mask-wearing would create a false sense of security (12). Critics argued those who wore masks would engage in compensating behaviors, such as failing to physically distance from others, resulting in a net increase in transmission (13). We directly test this hypothesis by measuring physical distancing."
  • Introduction: Encouraged mask-wearing at among everyone, even asymptomatic users.
  • Introduction: Tested different methods of communication about mask wearing in the pilot, but settled on one core intervention.
  • Introduction: Study powered by "symptomatic seroprevalence", determined by blood samples at the endline from anyone who reported studies, and tracks those who are both symptomatic (reporting symptoms of COVID-19) and seropositive (blood test reveals presence/history of COVID-19). It does not show asymptomatic seropositive individuals.
  • Results: 125,053 provided baseline info -> 336,010 provided symptom data at wk 9 and/or 10. Of these, 27,160 reported COVID-like symptoms. Of these, 10,790 consented to blood draw. Much greater symptom data vs serotype data.
  • Primary Analysis: "Among Bangladeshi individuals examined, : In control villages 24.1% of observed individuals practiced physical distancing compared to 29.2% in intervention villages, an increase of 5.1% (a regression adjusted estimate of 0.05 [95% CI: 0.04,0.06]). Evidently, protective behaviors like mask-wearing and physical distancing are complements rather than substitutes: endorsing mask-wearing and informing people about its importance encouraged rural Bangladeshis to take the pandemic more seriously and engage in another form of self-protection. The increases in physical distancing were similar in cloth and surgical mask villages."
  • Primary Analysis: "We find no difference in the number of people observed in public areas between the treatment and control groups overall (Table S6)."
  • Primary Analysis: "Omitting symptomatic participants who did not consent to blood collection, symptomatic seroprevalence was 0.76% in control villages and 0.68% in the intervention villages. Because the fractions we are reporting omit non-consenters
    from the numerator but not the denominator, it is likely that the true rates of symptomatic seroprevalence are substantially higher (perhaps by 2.5 times, if non-consenters have similar seroprevalence to consenters).
  • Encouraging masking vs not encouraging masking: "The results in all specifications are the same: we estimate a roughly 9% decline in symptomatic seroprevalence in the treatment group (adjusted prevalence ratio (aPR) = 0.91 [0.82, 1.00]) for a 29 percentage point increase in mask wearing over 8 weeks."
  • We find clear evidence that surgical
    masks lead to a relative reduction in symptomatic seroprevalence of 11.1% (aPR = 0.89 [0.78,1.00]; control prevalence = 0.81%; treatment prevalence = 0.72%). Although the point estimates for cloth masks suggests that they reduce risk, the confidence limits include both an effect size similar to surgical masks and no effect at all. (aPR = 0.94 [0.78,1.10]; control: 0.67%; treatment: 0.61%).
  • Discussion: We found clear evidence that surgical masks are effective in reducing symptomatic seroprevalence of SARS-CoV-2. While cloth masks clearly reduce symptoms, we find less clear evidence of their impact on symptomatic SARS-CoV-2 infections, with the statistical significance depending on whether we impute missing values for non-consenting adults. The number of cloth mask villages (100) was half that for surgical masks (200), meaning that our results tend to be less precise.
    Additionally, we found evidence that surgical masks were no less likely to be adopted than cloth masks. Surgical masks have higher filtration efficiency, are cheaper, are consistently worn, and are better supported by our evidence as tools to reduce COVID-19.

Pro mask wearing in general: Yes, well evidenced.
Pro N-95 / KN-95: Not examined
Pro surgical mask: Yes, well evidenced. Recommendations are well reasoned: cheaper than cloth masks. Not compared to N-95.
Pro cloth mask: Inconclusive. May have some benefit--but cannot be disentangled from the differences due to promotion and behavioral effects of mark-wearing.
Greater high-risk behaviors due to mask mandates: none evidence though, even if they were, I would only feel comfortable generalizing to the culture and people where it was studied.

Other thoughts: This is an awesome study. This study tells us that promoting masks makes a difference and that surgical grade masks can make a difference. Something to be aware of is that a study recruiting 300,000 participants wasn't powerful enough to show us what effect cloth masks have, though an effect is suggested--this is difficult work and getting answers is not easy or cheap.

I couldn't find a completed clinical trial, applied generally comparing N-95 masks and other masks for COVID-19, but I can for healthcare workers and influenza.





Surgical mask vs N95 respirator for preventing influenza among health care workers: a randomized trial
Authors: Mark Loeb, Nancy Dafoe, James Mahony, Michael John, Alicia Sarabia, Verne Glavin, Richard Webby, Marek Smieja, David J D Earn, Sylvia Chong, Ashley Webb, Stephen D Walter
Publishing date: 4 Nov 2009
Publisher: JAMA (study)
Peer-reviewed?: Presumably
Where to access: https://clinicaltrials.gov/ct2/show/NCT00756574?term=N-95&recrs=e&draw=4&rank=2 -> https://pubmed.ncbi.nlm.nih.gov/19797474/
I don't have access to the full article, so at least this exploration will go faster:
Results: "Between September 23, 2008, and December 8, 2008, 478 nurses were assessed for eligibility and 446 nurses were enrolled and randomly assigned the intervention; 225 were allocated to receive surgical masks and 221 to N95 respirators. Influenza infection occurred in 50 nurses (23.6%) in the surgical mask group and in 48 (22.9%) in the N95 respirator group (absolute risk difference, -0.73%; 95% CI, -8.8% to 7.3%; P = .86), the lower confidence limit being inside the noninferiority limit of -9%"

Pro mask wearing in general: N/
Pro N-95 / KN-95: not evidenced over surgical mask, only studied influenza.
Pro surgical mask: not evidenced over 95s, only studied influenza
Pro cloth mask: not studied
Greater high-risk behaviors due to mask mandates: not studied

Other thoughts: a strong difference would have been good to see, but this study's design doesn't really tell us much of anything--all they hoped to show was that N95 masks weren't worse than surgical masks at protecting against influenza.



Filtration Efficiency, Effectiveness, and Availability of N95 Face Masks for COVID-19 Prevention
Authors: Caitlin M. Dugdale, MD1,2; Rochelle P. Walensky, MD, MPH1,2
Publishing date: 4 Nov 2009
Publisher: JAMA Internal Medicine (editorial)
Peer-reviewed?: No, not a study
Where to access: https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2769441

Not a study to digest, but there's some important discussion of N-95 related to other interventions here:

quote:

Importantly, the effectiveness of any mask also depends heavily on its real-world use; variability in mask filtration during clinical care may fluctuate more by mask adherence and fit than by marginal differences in laboratory-based filtration efficiency. In practicality, when worn properly, N95 masks are suffocating, uncomfortable, and difficult to tolerate for long durations. Best practices for N95 use require intermittent, individualized fit testing and a seal check on donning. Mask fit varies by facial shape and body habitus, and thus, once fit tested, ensuring fidelity to the same manufacturer and size is essential. Filtration efficiency of an N95 mask can also be compromised by even small amounts of facial hair in the area of the seal. Prolonged use of tightly fitting masks may result in facial bruising and abrasions, but bandages over these areas, such as the commonly seen wound barriers over the nasal bridge, interrupt the mask seal. Although a recent clinical trial6 reported similar and suboptimal self-reported adherence between outpatient health care personnel randomized to wear N95 masks vs medical masks (89% vs 90%), the study also demonstrated no difference in cases of laboratory-documented influenza—albeit a different respiratory virus—between the 2 groups. Acknowledging that adherence is likely higher amid the COVID-19 pandemic, mask efficiency observed in the laboratory likely reflects an upper bound of the effectiveness that would be observed in clinical settings.

This paragraph is important because it explains the limits of N-95 masks: mainly that to reach full effectiveness, they have to be individually fit tested, seal checked and instructions must be adhered to.

Loucks
May 21, 2007

It's incwedibwe easy to suck my own dick.


I confess I'm curious what "science" would be required to advocate for the use of disposable N95 respirators or elastomeric respirators with P100 filters. The filtration standards are public record. The FUD that surrounds non-institutional respiratory PPE use is entirely overblown, as fit testing procedures are also public record and not difficult to perform in the case of elastomerics. Or is the idea that the burden of proving that e.g., a translucent Disney-branded neck gaiter is less effective than a NIOSH-certified respirator falls on the person making that claim? I've tried for almost two years now to convince people to wear at least N95s, and while some people are receptive to published safety standards a disappointing percentage just get mad and point at CDC's guidance that people strap just about anything they can find across their faces as evidence that wearing actual PPE is crazy.

Anyway, I've basically given up on convincing people because the effort is usually wasted and tends to result in highly emotional backlash. If anyone is genuinely interested in maximizing protection both 3M and Honeywell make comfortable, effective elastomeric respirators that are far more comfortable than any cloth or disposable mask.

SMEGMA_MAIL
May 4, 2018
my avatar is better than my posting

I’m going to make a not peer reviewed claim and talk about my time working around infectious diseases including a COVID ICU- simply loving washing your hands after you touch anything other people touch goes an insanely long way. I know it’s obvious but seeing it firsthand between people who followed procedure and who didn’t made something that I knew but didn’t “feel” it intuitively obvious to me.

If you wear proper PPE and wash your hands before and after touching anything potentially problematic and throughout the day you almost certainly won’t catch much.

ded
Oct 27, 2005

Kooler than Jesus


per my wife who has been treating covid patients for 2 years - there is much more concern that the newer variants are airborne. wearing a proper n95 is much more important than before.

Marshal Prolapse
Jun 23, 2012

"That fucker thinks he can take on the Red Army? I fucked Germany, I think I can take a flesh lump in a fucking waistcoat."


ded posted:

per my wife who has been treating covid patients for 2 years - there is much more concern that the newer variants are airborne. wearing a proper n95 is much more important than before.

I'm actually switching our kids to K95s due to that and also after their school district sent out a letter saying volunteers no longer need proof of vaccination or a negative test. :wtc:

mlmp08
Jul 11, 2004


Nap Ghost

quote:

I've tried for almost two years now to convince people to wear at least N95s, and while some people are receptive to published safety standards a disappointing percentage just get mad and point at CDC's guidance that people strap just about anything they can find across their faces as evidence that wearing actual PPE is crazy.

The CDC’s guidance does not say this.

quote:

Anyway, I've basically given up on convincing people because the effort is usually wasted and tends to result in highly emotional backlash.

It could be that you are misrepresenting the CDC guidance and that they noticed the misrepresentation. Or they just don’t want to buy and wear reusable half-face 3M respirators. They are affordable, if you wear N95 level protection at all times, but most people do not, and they’re not exactly kind to various hairstyles and looking “normal.”

Personally, I just wear bulk-purchased KN95s from a company sample-tested by the NPPTL and keep a backup supply of surgical masks in the car. I know it would be cheaper to buy and wear a half-mask 3M reusable respirator, but it looks pretty absurd and is contrary to uniform expectations, whereas N95/KN95 is not.

Loucks
May 21, 2007

It's incwedibwe easy to suck my own dick.


mlmp08 posted:

The CDC’s guidance does not say this.

I urge you to Google “hyperbole.”

piL
Sep 20, 2007
(__|\\\\)

Taco Defender

Loucks posted:

I confess I'm curious what "science" would be required to advocate for the use of disposable N95 respirators or elastomeric respirators with P100 filters. The filtration standards are public record. The FUD that surrounds non-institutional respiratory PPE use is entirely overblown, as fit testing procedures are also public record and not difficult to perform in the case of elastomerics. Or is the idea that the burden of proving that e.g., a translucent Disney-branded neck gaiter is less effective than a NIOSH-certified respirator falls on the person making that claim? I've tried for almost two years now to convince people to wear at least N95s, and while some people are receptive to published safety standards a disappointing percentage just get mad and point at CDC's guidance that people strap just about anything they can find across their faces as evidence that wearing actual PPE is crazy.

Anyway, I've basically given up on convincing people because the effort is usually wasted and tends to result in highly emotional backlash. If anyone is genuinely interested in maximizing protection both 3M and Honeywell make comfortable, effective elastomeric respirators that are far more comfortable than any cloth or disposable mask.

I'm sympathetic. But all of these things are tied up among surprisingly difficult moral quandaries. Determining which action fits your morals become easier with a greater understanding of fact and my hope is that, by using evidence, we can remove some of the emotion from the question.

Some of this is scientific, some of this is philosophical. Whether it seems that way or not, you're asking people to weigh their moral values based on an imperfect understanding of fact. With different assumptions will come different conclusions, but they'll be enforced as norms via social isolation. We should expect some emotion.

The big factor people often have to weigh is, "how much is enough?" You can always be more safe. N95 masks are probably safer than surgical masks which are probably safer than translucent Disney-branded neck gaiters. Fitted N95 masks used no more than once per patient exposure are probably safer than unfitted N-95 masks worn for several days. Self contained breathing apparatuses are probably safer. Never leaving the house, separating from and family members or friends who do go outside of the house and only receiving delivered goods after they've been left outside under sun exposure is probably even better--at least from this one particular threat.

More data and better studies can help us refine these normative positions and make more convincing arguments. I've personally landed on buying a bunch of KN95 masks and reusing them. But the reason I landed on that was mostly tied to that act being easy enough--if I couldn't find them couldn't afford them, wasn't willing to take them from the market, then I might pursue cloth masks like I did in the first several months of the pandemic. If had unlimited money and no concerns, I might keep a stockpile of hundreds and change several a day--I'm fairly certain that my strategy was heavily based on access, but unless I intentionally acknowledge the bias, I'm likely to justify it post hoc with all sorts of reasons.

mlmp08
Jul 11, 2004


Nap Ghost

piL posted:

More data and better studies can help us refine these normative positions and make more convincing arguments. I've personally landed on buying a bunch of KN95 masks and reusing them. But the reason I landed on that was mostly tied to that act being easy enough--if I couldn't find them couldn't afford them, wasn't willing to take them from the market, then I might pursue cloth masks like I did in the first several months of the pandemic. If had unlimited money and no concerns, I might keep a stockpile of hundreds and change several a day--I'm fairly certain that my strategy was heavily based on access, but unless I intentionally acknowledge the bias, I'm likely to justify it post hoc with all sorts of reasons.

Yeah basically. I got a 100-pack of KN95s and wear them a couple days each. I wore mostly cloth masks on deployment back when supply chains were worse and mail was sometimes on hold for several weeks. When there were bad breakouts we’d maybe get a medical N95 issued and be told to wear it for weeks, until it literally fell apart.

Otherwise, I avoid public spaces, eat out never (pickup/delivery sure), and I have a collection of over the top 3M gear for going to potentially high-density crowd locations if I have to.

I also self-test after anything resembling a scare and all travel now that tests are more available.

So collectively, I’ve spent maybe 4-500 hundred dollars on PPE and tests, which I think is worth it, but it isn’t nothing!

McNally
Sep 12, 2007

Ask me about Proposition 305


Do you like muskets?


Loucks posted:

I urge you to Google “hyperbole.”

Don't post like this. It doesn't win cool points, just earns posting vacations.

Loucks
May 21, 2007

It's incwedibwe easy to suck my own dick.


McNally posted:

Don't post like this. It doesn't win cool points, just earns posting vacations.

No problem. I’m not sure how else to respond when someone takes obvious hyperbole and treats it like a serious argument to score their own points off of. Guess I’ll just ignore them next time.

McNally
Sep 12, 2007

Ask me about Proposition 305


Do you like muskets?


Loucks posted:

No problem. I’m not sure how else to respond when someone takes obvious hyperbole and treats it like a serious argument to score their own points off of. Guess I’ll just ignore them next time.

Or presume good faith and point out that it was hyperbole. Misunderstandings happen.

Midjack
Dec 24, 2007





I've had a couple of 3M half masks and a generous supply of p100 carts for years used for airbrushing my little robot models, but work prohibits masks with exhaust valves so I'm in fabric and disposable hell with everyone else 9-5.

mlmp08
Jul 11, 2004


Nap Ghost

Midjack posted:

I've had a couple of 3M half masks and a generous supply of p100 carts for years used for airbrushing my little robot models, but work prohibits masks with exhaust valves so I'm in fabric and disposable hell with everyone else 9-5.

That too. Exhaust valves are a no-go.

Loucks
May 21, 2007

It's incwedibwe easy to suck my own dick.


Posting again on the off chance that anyone in IVFW is looking for recommendations for NIOSH-certified PPE. I've tried quite a few different N95s over this thing, and the most comfortable ones I've found are the 3M Auras (models 9205 & 9210+) which retail for <$2 each and are good for at least 40 hours of use unless you're hanging out in a coal mine or something. You can wear these things for a full 8 hours without issue, at least I can. They come individually packaged, fold flat so it's easy to carry a spare, have no exhalation valve, and have a broad nose section so it's very easy to get a great seal and avoid leakage assuming willingness to shave off goony neckbeards. This last is especially helpful for those with glasses, as I at least have not found any sub-N95 (e.g., KF94, KN95) masks that don't leak enough to cause fogging problems.

The 9205 model is available at some hardware stores like Home Depot, but it has rubberized straps that can pull longer hair. The 9210+ isn't available in any b&m stores afaik, but can be ordered online from quite a few vendors. Would avoid Amazon due to counterfeiting concerns.

Midjack
Dec 24, 2007





Loucks posted:

Posting again on the off chance that anyone in IVFW is looking for recommendations for NIOSH-certified PPE. I've tried quite a few different N95s over this thing, and the most comfortable ones I've found are the 3M Auras (models 9205 & 9210+) which retail for <$2 each and are good for at least 40 hours of use unless you're hanging out in a coal mine or something. You can wear these things for a full 8 hours without issue, at least I can. They come individually packaged, fold flat so it's easy to carry a spare, have no exhalation valve, and have a broad nose section so it's very easy to get a great seal and avoid leakage assuming willingness to shave off goony neckbeards. This last is especially helpful for those with glasses, as I at least have not found any sub-N95 (e.g., KF94, KN95) masks that don't leak enough to cause fogging problems.

The 9205 model is available at some hardware stores like Home Depot, but it has rubberized straps that can pull longer hair. The 9210+ isn't available in any b&m stores afaik, but can be ordered online from quite a few vendors. Would avoid Amazon due to counterfeiting concerns.

I will second this recommendation; I got a couple of boxes of 9205s at Home Depot a couple of weeks ago and have been wearing one for the last couple of weeks.

citybeatnik
Mar 1, 2013

You Are All
WEIRDOS





If someone could actually point me to a kn95 mask that would actually fit my drat freakishly large head I'll be more than happy to wear them. I stick with fabric because at least i can get multilayered ones that can cover both my mouth and nose at the same time.

Midjack
Dec 24, 2007





citybeatnik posted:

If someone could actually point me to a kn95 mask that would actually fit my drat freakishly large head I'll be more than happy to wear them. I stick with fabric because at least i can get multilayered ones that can cover both my mouth and nose at the same time.

What's the specific challenge? Nose to mouth distance, having the Pyramid of Giza stuck to the front of your face (my issue)?

Wang Commander
Dec 27, 2003
Probation
Can't post for 29 days!


Moldex N95 is good for Italian or Serb level nose not sure it can do bigger tho

citybeatnik
Mar 1, 2013

You Are All
WEIRDOS





Midjack posted:

What's the specific challenge? Nose to mouth distance, having the Pyramid of Giza stuck to the front of your face (my issue)?

Nose to mouth distance combined with distance to my ears. It seems that I get an actual seal/coverage with fabric.

shame on an IGA
Apr 8, 2005

Get into shit, let it out like diarrhea
Got burnt once, that was only gonorrhea




Try the Powecom FFP2 masks on amazon, they've got over the head bands instead of ear loops and I've been pleased with them despite the smallish size (for me. I have a freakishly big head, they still get a good seal)

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rifles
Oct 8, 2007
is this thing working

I got a pack of 3m Auras to try and I'm 100% sold. They're easy to breathe in, don't fog my glasses at all, and are so comfortable I don't feel the need to take it on and off outside of buildings when I'm doing stuff. I wore kn95s this entire last semester and I wish I had tried these sooner, my ears would have thanked me. Going to get a bigger box and wear them exclusively. Night and day improvement over 8210s as well (which I started the pandemic with 3 boxes of because reasons) for n95 protection.

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