Studies have found that a combination of multi-layered cotton and chiffon/silk masks prevents intake of both large and small droplets. Silk/chiffon act magnetically on smaller particles to keep you from breathing them in, while the thick cotton layers stop large droplets. The aggregate effect is similar to N95, but more washable and reusable. It blows my mind that this was discovered a couple months ago and the government still hasn’t funded the mass production of such masks. After I read the study, I bought 2 masks on Etsy.com: a multilayered cotton mask and a silk mask. I wear both when I go out. What’s great is that I don’t just protect others from me, but I also protect myself from others to a large extent (as opposed to just wearing the cotton mask). As for comfort, silk is light and thin, so it doesn’t add any noticeable discomfort on top of the cotton mask.
Note: Newer studies have found that even just a thick cotton mask does somewhat protect you (not as much as cotton + silk of course, but they protect others from you quite effectively). You still need to be careful, generally avoid indoor environments with strangers, and socially distance. Not that that disclaimer is super necessary, because other studies have found that masks do not make people behave more recklessly :) If anything, they make you more careful and acutely aware of COVID risks.
> Newer studies have found that even just a thick cotton mask does somewhat protect you
No they haven't. If the effect of masks was so strong it would be easy to find that when we do trials. We've done the trials and we struggle to see the effect. Once we drop down the quality requirements we start to see an effect, but even that is mild.
> Although direct evidence is limited, the optimum use of face masks, in particular N95 or similar respirators in health-care settings and 12–16-layer cotton or surgical masks in the community, could depend on contextual factors; action is needed at all levels to address the paucity of better evidence. Eye protection might provide additional benefits. Globally collaborative and well conducted studies, including randomised trials, of different personal protective strategies are needed regardless of the challenges, but this systematic appraisal of currently best available evidence could be considered to inform interim guidance
There's no way to spin phrases like "direct evidence is limited" and "paucity of evidence" to mean "we've got good quality evidence that shows an effect".
Remember: even if a mask doesn't effectively filter out very small particles, it still restricts the velocity of air passing through it. This means aerosolized particles will not travel as far.
> Non-medical facemasks include a variety of products. There is no reliable evidence of the effectiveness of non-medical facemasks in community settings. There is likely to be substantial variation in effectiveness between products. However, there is only limited evidence from laboratory studies of potential differences in effectiveness when different products are used in the community.
> Given the low prevalence of COVID-19 currently, even if facemasks are assumed to be effective, the difference in infection rates between using facemasks and not using facemasks would be small.Assuming that 20% of people infectious with SARS-CoV-2 do not have symptoms,and assuming a risk reduction of 40% for wearing facemask, 200000 people would need to wear facemasks to prevent one new infection per week in the current epide-miological situation.
They have a plausible mechanism of action, but they also have plausible mechanisms of harm. The above link includes one trial where they appeared to be harmful:
> It is debatable whether any of these results could be applied to the transmission of SARs-CoV-2. Only one randomised trial (n=569) included cloth masks. This trial found ILI rates were 13 times higher in Vietnamese hospital workers allocated to cloth masks compared to medical/surgical masks, RR 13.25, (95%CI 1.74 to 100.97) and over three times higher when compared to no masks,* RR 3.49 (95%CI 1.00 to 12.17). 4
This is potentially because the masks start to lose effectiveness as soon as you put them on. DIY cloth masks soon become waterlogged with condensation, and then when you breath you push out aerosolised drops.
> This study was conducted to check the efficacy of face masks in limiting bacterial dispersal when worn continuously in Operation Theater. A comparison was done to find out difference between fabric and two ply disposable masks. The first sample was collected prior to wearing the mask, using cough plate method holding a blood agar plate approximately 10 -12 centimeters away from the mouth. the personnel were asked to produce “ahh” phonation. Participants were then asked to don the face mask, continue routine work and report to the study center located inside the theater for further sample collections at designated intervals of 30, 60, 90, 120 and 150 minutes after wearing the fabric mask made of cotton. the study was replicated on immediate next day using two ply disposable mask keeping all the other conditions and personnel exactly the same. Bacterial counts before wearing the mask were 5.36±4.38 and 5.7±2.99 on day 1 and day 2 of study. Bacterial counts were 0.96±1.06 (P<0.001) and 0.7±0.87 (P<0.001) at 30 min; 2.33±1.42 (P<0.001) and 2.36±1.03 (P<0.001) at 60 min; 3.23±1.54 (P=0.007) and 4.16±1.78 (P=0.011) at 90 min; 5.63±4.02 (P=0.67) and 4.9±1.98 (P=0.161) at 120 min and 7.03±4.45 (P=0.019) and 5.6±2.21 (P=0.951) at 150min respectively for fabric and two ply disposable mask. Counts were near pre-wear level in about two hours irrespective of the type of mask. There was no significant difference between cotton fabric and two ply disposable masks. Face masks significantly decreased bacterial dispersal initially but became almost ineffective after two hours of use.
My point is that we don't have the evidence to say whether masks work or not. You posting links to arstechnica and un-peer-reviewed pre-prints supports my point, doesn't it? If we had a Cochrane Collaboration meta analysis saying masks worked everyone would be posting that.
> There is no reliable evidence of the effectiveness of non-medical facemasks in community settings.
There has been only very limited study of non-medical (cloth) masks so far, because there was not a prior crisis that NEEDED them (where surgical mask supplies were insufficient). The fundamental problem with most of your points is that lack of research on effectiveness is NOT the same thing as proof of ineffectiveness.
We can assume that most cloth masks are probably not AS effective as surgical masks or N95 masks (although some materials can achieve surprisingly good filtration), but that's not the same thing as saying they're useless either. Especially true for models with good fit and the ability to install filters. But even a modest reduction in R-effective can greatly reduce the number of number of people infected over time.
Beyond that, I'm not going to waste time going point by point in debate with someone determined to "disprove" guidance from the best available medical authorities.
Mask wearing provides minimal benefits against droplet transmission, but they do nothing at all for small droplet aerosol transmission.