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To what degree does a cloth mask protect the wearer? Enough that high risk people should feel safe going out with one on? Because that's the messaging that a

To what degree does a cloth mask protect the wearer? Enough that high risk people should feel safe going out with one on? Because that's the messaging that a lot of people got. "Masks work" [if enough people are wearing them in congregate settings] might make sense to some tiny subset of people who obsessively follow the current understanding of various covid mitigation strategies. For people who don't, that reads as "masks protect you from covid", which I don't think is a claim that anybody serious is even making. "Masks work", without the additional context and nuance is itself misinformation.

Retric 5y ago
It’s a sliding scale. Basically if you have a 90+% chance of infection such as extended close contact with a sick spouse cloth masks are not particularly useful. However, when used properly they can be quite effective for people at low risk for transmission potentially blocking more than 1/2 of infections. For example, surgical masks with ties provided 71.5 percent filtration, while surgical masks with ear loops only provided 38.1 percent. … a three-layer knitted cotton mask blocked an average of 26.5 percent of particles in the chamber, while a washed, two-layer woven nylon mask with a filter insert and metal nose bridge blocked 79 percent of particles on average. Other masks scored somewhere in between. They also tested a variety of modifications to improve the fit of commercially available medical procedure masks, like tightening ear loops, placing rubber bands over the top and bottom of the mask to reduce gaps, and placing a cut-out piece of nylon stocking over the mask to seal the gaps. The filtration ability improved by 60.3 to 80.2 percent depending on the modification made. As the fit of the medical procedure masks improved, so did their filtration efficiency. https://www.epa.gov/sciencematters/epa-researchers-test-effectiveness-face-masks-disinfection-methods-against-covid-19 https://www.epa.gov/sciencematters/epa-researchers-test-effe... IMO, saying masks work is perfectly reasonable even if they don’t provide 100% protection.

Retric 5y ago

It’s a sliding scale. Basically if you have a 90+% chance of infection such as extended close contact with a sick spouse cloth masks are not particularly useful. However, when used properly they can be quite effective for people at low risk for transmission potentially blocking more than 1/2 of infections. For example, surgical masks with ties provided 71.5 percent filtration, while surgical masks with ear loops only provided 38.1 percent. … a three-layer knitted cotton mask blocked an average of 26.5 percent of particles in the chamber, while a washed, two-layer woven nylon mask with a filter insert and metal nose bridge blocked 79 percent of particles on average. Other masks scored somewhere in between. They also tested a variety of modifications to improve the fit of commercially available medical procedure masks, like tightening ear loops, placing rubber bands over the top and bottom of the mask to reduce gaps, and placing a cut-out piece of nylon stocking over the mask to seal the gaps. The filtration ability improved by 60.3 to 80.2 percent depending on the modification made. As the fit of the medical procedure masks improved, so did their filtration efficiency. https://www.epa.gov/sciencematters/epa-researchers-test-effectiveness-face-masks-disinfection-methods-against-covid-19 https://www.epa.gov/sciencematters/epa-researchers-test-effe... IMO, saying masks work is perfectly reasonable even if they don’t provide 100% protection.