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Low-cost measurement of facemask efficacy for filtering expelled droplets

advances.sciencemag.org

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Re: Low-cost measurement of facemask efficacy for filtering expelled droplets

#31

Post by throw_away »

russholmes wrote: post #30
aflag wrote: post #23

Earlier quoted context omitted.

I've seen that idea being tossed around, but are there any sort of studies showing that the increased face touching can indeed make the virus spread more than not wearing masks? It's a geniune question, I'd like to see studies related to that. For me, it's not really obvious that more face touching (even if that happens in significant numbers across the population), causes the virus to spread more than it would have…

I think the reason that various authorities advised against masks is political - there simply weren't enough and to direct the supply to clinical workers.

Which is damning in that they treated us like children who couldn't handle the truth and were also so unimaginative that they did not consider alternative face coverings.

Re: Low-cost measurement of facemask efficacy for filtering expelled droplets

#32

Post by lm28469 »

Kiro wrote: post #16
techsupporter wrote: post #8

Earlier quoted context omitted.

I think the broader point is one that still stands: wearing literally anything over your nose and mouth is shown, by this study, to cut droplet by at least 50%. Even the cotton varieties cut it from 70% to 90%. So...people need to just slap something over their two air exchanging orifices on their faces before leaving the house and contribute to the our greater health. You're right about the differences in effectiven…

You touch your face more when adjusting the mask so if it's not efficient enough it may be a net negative. Edit: This is one of the main reason the Scandinavian countries recommend against _all_ mask use (including N95) so not sure why I'm getting downvoted for merely saying an inefficient mask could have that problem.

I find it hard to believe that any experiments would back up that fact. Do people put their fingers in their eyes/nose/mouth when adjusting their masks ?

Surely having everyone wear a mask is more efficient than banning masks because a small fraction of mask wearers would catch covid when readjusting their masks.

Re: Low-cost measurement of facemask efficacy for filtering expelled droplets

#33

Post by russholmes »

Kiro wrote: post #28
aflag wrote: post #23

Earlier quoted context omitted.

I've seen that idea being tossed around, but are there any sort of studies showing that the increased face touching can indeed make the virus spread more than not wearing masks? It's a geniune question, I'd like to see studies related to that. For me, it's not really obvious that more face touching (even if that happens in significant numbers across the population), causes the virus to spread more than it would have…

I've only heard what the state epidemiologists say but here's the Finnish study that the current recommendations are based on: https://yle.fi/uutiset/osasto/news/report_little_or_no_benef... With that said, Finland is re-evaluating face masks it as we speak so it may change.

According to this research in the Lancet, masks help but not as much as physical distancing.

2 m distance reduces risk by 10x face mask reduces risk by 6x eye protection by 5x There is some uncertainty in these figures

https://www.thelancet.com/journals/lancet/article/PIIS0140-6...

Re: Low-cost measurement of facemask efficacy for filtering expelled droplets

#34

Post by superkuh »

Nice to see some empirical validation of valved N95 masks still being better than the vast majority of other "masks" when it comes to protecting other people. And of course valved N95 masks are the gold standard for cheap masks (not full organic vapor gas masks, etc) even outperforming non-valved N95 in protection of self because of the valve preventing them from becoming unsealed during peak outflow. And of course they are much more comfortable to wear for long periods and during heavy work.

I just wish the US government would go all in on production of real, effective, fit N95 masks and distribute them to everyone.

Re: Low-cost measurement of facemask efficacy for filtering expelled droplets

#35

Post by russholmes »

throw_away wrote: post #31
russholmes wrote: post #30

Earlier quoted context omitted.

I think the reason that various authorities advised against masks is political - there simply weren't enough and to direct the supply to clinical workers.

Which is damning in that they treated us like children who couldn't handle the truth and were also so unimaginative that they did not consider alternative face coverings.

The government communication in the UK has been lamentable. Confusing, inconsistent and patronising. On the other hand, we had idiots who stripped the supermarket shelves of toilet rolls and canned tomatoes for months despite being implored not to do so. If they had gone after the masks...

Re: Low-cost measurement of facemask efficacy for filtering expelled droplets

#36

Post by lol2143651 »

aflag wrote: post #23
Kiro wrote: post #16

Earlier quoted context omitted.

You touch your face more when adjusting the mask so if it's not efficient enough it may be a net negative. Edit: This is one of the main reason the Scandinavian countries recommend against _all_ mask use (including N95) so not sure why I'm getting downvoted for merely saying an inefficient mask could have that problem.

I've seen that idea being tossed around, but are there any sort of studies showing that the increased face touching can indeed make the virus spread more than not wearing masks? It's a geniune question, I'd like to see studies related to that. For me, it's not really obvious that more face touching (even if that happens in significant numbers across the population), causes the virus to spread more than it would have…

Results

> The rates of all infection outcomes were highest in the cloth mask arm, with the rate of ILI statistically significantly higher in the cloth mask arm (relative risk (RR)=13.00, 95% CI 1.69 to 100.07) compared with the medical mask arm. Cloth masks also had significantly higher rates of ILI compared with the control arm. An analysis by mask use showed ILI (RR=6.64, 95% CI 1.45 to 28.65) and laboratory-confirmed virus (RR=1.72, 95% CI 1.01 to 2.94) were significantly higher in the cloth masks group compared with the medical masks group. Penetration of cloth masks by particles was almost 97% and medical masks 44%.

Conclusions

> This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection. Further research is needed to inform the widespread use of cloth masks globally. However, as a precautionary measure, cloth masks should not be recommended for HCWs, particularly in high-risk situations, and guidelines need to be updated.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4420971/

Re: Low-cost measurement of facemask efficacy for filtering expelled droplets

#37

Post by dragontamer »

Kiro wrote: post #16
techsupporter wrote: post #8

Earlier quoted context omitted.

I think the broader point is one that still stands: wearing literally anything over your nose and mouth is shown, by this study, to cut droplet by at least 50%. Even the cotton varieties cut it from 70% to 90%. So...people need to just slap something over their two air exchanging orifices on their faces before leaving the house and contribute to the our greater health. You're right about the differences in effectiven…

You touch your face more when adjusting the mask so if it's not efficient enough it may be a net negative. Edit: This is one of the main reason the Scandinavian countries recommend against _all_ mask use (including N95) so not sure why I'm getting downvoted for merely saying an inefficient mask could have that problem.

> You touch your face more when adjusting the mask so if it's not efficient enough it may be a net negative.

Keep hand sanitizer in your pocket. Whenever you touch the mask, sanitize your hands. Both before you touch (in case you touched a COVID19 infected surface, you don't want to add COVID19 to the mask), and after you touch (in case your mask prevented COVID19 from entering your lungs, you don't want to contaminate other things anymore)

Problem solved. At my work, there's hand-sanitizer everywhere now. I don't even need to reach into my pockets anymore.

Or #2: don't touch your mask. Ever. That's how doctors/nurses do it. The hand-sanitizer crutch is what I do because I'm not as good as a doctor/nurse with my discipline. But I'm training myself to never touch the mask.

Re: Low-cost measurement of facemask efficacy for filtering expelled droplets

#38

Post by mannykannot »

throw_away wrote: post #31
russholmes wrote: post #30

Earlier quoted context omitted.

I think the reason that various authorities advised against masks is political - there simply weren't enough and to direct the supply to clinical workers.

Which is damning in that they treated us like children who couldn't handle the truth and were also so unimaginative that they did not consider alternative face coverings.

There is now, and was then, plenty of evidence to suppose that enough people would not handle the truth responsibly, and would panic-buy masks rather than adopt alternatives.

Re: Low-cost measurement of facemask efficacy for filtering expelled droplets

#39

Post by Johnjonjoan »

russholmes wrote: post #35
throw_away wrote: post #31

Earlier quoted context omitted.

Which is damning in that they treated us like children who couldn't handle the truth and were also so unimaginative that they did not consider alternative face coverings.

The government communication in the UK has been lamentable. Confusing, inconsistent and patronising. On the other hand, we had idiots who stripped the supermarket shelves of toilet rolls and canned tomatoes for months despite being implored not to do so. If they had gone after the masks...

Yes we should not have taken masks that would go to the NHS but don't forget those masks should have been in government stockpiles well out of reach. How can we blame and punish the publics self control (or lack of it) when it's a government failure that caused the issue. Had we all bought masks and the state made them instead of redundant hospitals perhaps we would be in a much better place (less NHS casualties and physical/mental suffering).

All in all it just doesn't sit right with me to justify the government's decision without mentioning they were the ones that put us in the position where it had to be made.

Re: Low-cost measurement of facemask efficacy for filtering expelled droplets

#40

Post by ncarroll »

russholmes wrote: post #30
aflag wrote: post #23

Earlier quoted context omitted.

I've seen that idea being tossed around, but are there any sort of studies showing that the increased face touching can indeed make the virus spread more than not wearing masks? It's a geniune question, I'd like to see studies related to that. For me, it's not really obvious that more face touching (even if that happens in significant numbers across the population), causes the virus to spread more than it would have…

I think the reason that various authorities advised against masks is political - there simply weren't enough and to direct the supply to clinical workers.

I personally think one aspect that doesn't get much attention is the matter of public education. At the arrival of the pandemic here in Germany the initial advice was to seriously implement hygiene rules: 1.) Wash hands thoroughly and often, 30 sec long, plenty of regular household brand hand soap, 2.) When coughing or sneezing, turn away from others and put your elbow in front of your face and 3.) Keep distance of minimum 1.5 meters and 4.) Limit contact with people outside your home environment wherever possible.

Assuming everyone followed this advice, at that particular moment we didn't need masks so much (most people were in lockdown anyway) and besides the fact that there were not enough medical masks to go around, there was more danger in using generic face coverings than not because the average Joe didn't know how to do so safely and the virus was not yet under any sort of control.

Around Mid-May, we had a different circumstance. The general public had taken the hygiene rules to heart and been in lockdown quite awhile and the sun came out - Spring sprang, the numbers went down (thanks to lots of cooperation from the general public) and that was when the public education effort went in to the next phase: To give official advice and instruction on how to properly handle face coverings in a way that they help instead of hinder.

Meanwhile everyone, even Grandparents, my mother, and some people's recalcitrant Uncles know how to use Skype and Zoom. We wash hands like surgeons, we can and do handle face coverings without making ourselves sick and I think, for a public education effort that started 5 months ago and was directed at 90 million people, that is simply huge. I try to remain wary of the impulse to judge what we did yesterday with what we know today.

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