Since you requested feedback, here are some quick thoughts:
While I very much hope Cameroon is able to bring COVID under control, it seems like this could be difficult based on what we’ve seen in other countries. So the part of your plan that I’m most optimistic about is the mask making, because I think that could save lives even if COVID is not brought under control. Somewhere I read (can’t remember where unfortunately) that if you wear a mask, then you’ll end up inhaling a smaller number of viral particles if you get exposed to an infected person, and inhaling a smaller number of viral particles tends to give you a milder case, which means you’re more likely to acquire immunity without putting your life at risk.
So I’d encourage you think about questions like: After we practice explaining the mask-making process in our workshops, can we find a way to explain mask-making via radio / flyers / newspaper articles? Or can we tell everyone at our mask-making workshops that they should run their own mask-making workshops for their family and friends and so on, so the mask-making knowledge spreads through the population that way?
Additionally, from what I’ve read some homemade masks are much more effective than others. Some snippets from my notes on mask effectiveness:
The test produced a few clear winners. While droplets from the average cough traveled around eight feet from an uncovered face, they went only 2.5 inches when produced behind a mask made of two layers of simple cotton quilting fabric. A mask made from a folded handkerchief produced droplets that traveled a bit over a foot. A loose, single-ply cotton bandana didn’t fare as well: While it prevented some fluid release, the cough’s plume still traveled nearly four feet.
“Whenever you have the option, use tightly woven fabric that has minimal leakage,” Verma concludes. “Any sort of covering is better than none.”
Thicker, more densely woven cotton fabrics are best, such as quilting cotton or cotton sheets. Stretchy knits aren’t ideal. Hold the fabric up to the light: The fewer tiny holes you can see, the better it will work to filter droplets.
The fabric should be a woven fabric, not a knitted fabric. What’s the difference? Woven fabrics don’t stretch much, so when you tie it around your face, the tiny holes between the threads don’t get bigger and let in more viruses.
In recent tests, HEPA furnace filters scored well, as did vacuum cleaner bags, layers of 600-count pillowcases and fabric similar to flannel pajamas. Stacked coffee filters had medium scores. Scarves and bandanna material had the lowest scores, but still captured a small percentage of particles.
If you don’t have any of the materials that were tested, a simple light test can help you decide whether a fabric is a good candidate for a mask.
“Hold it up to a bright light,” said Dr. Scott Segal, chairman of anesthesiology at Wake Forest Baptist Health who recently studied homemade masks. “If light passes really easily through the fibers and you can almost see the fibers, it’s not a good fabric. If it’s a denser weave of thicker material and light doesn’t pass through it as much, that’s the material you want to use.”
...
Dr. Wang’s group tested two types of air filters. An allergy-reduction HVAC filter worked the best, capturing 89 percent of particles with one layer and 94 percent with two layers. A furnace filter captured 75 percent with two layers, but required six layers to achieve 95 percent. To find a filter similar to those tested, look for a minimum efficiency reporting value (MERV) rating of 12 or higher or a microparticle performance rating of 1900 or higher.
The problem with air filters is that they potentially could shed small fibers that would be risky to inhale. So if you want to use a filter, you need to sandwich the filter between two layers of cotton fabric. Dr. Wang said one of his grad students made his own mask by following the instructions in the C.D.C. video, but adding several layers of filter material inside a bandanna.
Dr. Wang’s group also found that when certain common fabrics were used, two layers offered far less protection than four layers. A 600 thread count pillow case captured just 22 percent of particles when doubled, but four layers captured nearly 60 percent. A thick woolen yarn scarf filtered 21 percent of particles in two layers, and 48.8 percent in four layers. A 100 percent cotton bandanna did the worst, capturing only 18.2 percent when doubled, and just 19.5 percent in four layers.
...
The best-performing designs were a mask constructed of two layers of high-quality, heavyweight “quilter’s cotton,” a two-layer mask made with thick batik fabric, and a double-layer mask with an inner layer of flannel and outer layer of cotton.
...
Bonnie Browning, executive show director for the American Quilter’s Society, said that quilters prefer tightly woven cottons and batik fabrics that stand up over time. Ms. Browning said most sewing machines can handle only two layers of fabric when making a pleated mask, but someone who wanted four layers of protection could wear two masks at a time.
...adding a layer of nylon stocking over the masks minimized the flow of air around the edges of the masks and improved particle filtration efficiency for all masks, including all commercial products tested. Use of a nylon stocking overlayer brought the particle filtration efficiency for five of the ten fabric masks above the 3M surgical mask baseline...
So it’s probably worth doing some research to figure out the best mask design from the perspective of effectiveness, ease of explaining how to create, and likelihood that people in the Santa Division will be able to acquire the necessary materials, if you haven’t already done this.
This is so cool! Actually EA Cameroon has done this research and they recommended using socks. However, all the resources will specify that any fabric works, as long as it covers mouth and nose.
And yes, I should write an update. The mask-making will be explained via radio and also taught to community leaders who will then be able to run the workshops. It is actually a great idea to schedule these workshops. Everyone will be encouraged to share the general information regarding preventive measures.
Yes. In terms of percentage, how less effective are 4 layers of woven fabric in preventing the spread of coronavirus than 4 layers of knitted fabric? Than 2 layers of woven fabric? The idea is to have at least 4 layers of the sock (after folding) or at least 2 layers of other fabric. In preventing breathing in the virus?
However, I’m more inclined to trust Johns Hopkins. But maybe the author of the Johns Hopkins article would have interesting opinions on the above link.
Since you requested feedback, here are some quick thoughts:
While I very much hope Cameroon is able to bring COVID under control, it seems like this could be difficult based on what we’ve seen in other countries. So the part of your plan that I’m most optimistic about is the mask making, because I think that could save lives even if COVID is not brought under control. Somewhere I read (can’t remember where unfortunately) that if you wear a mask, then you’ll end up inhaling a smaller number of viral particles if you get exposed to an infected person, and inhaling a smaller number of viral particles tends to give you a milder case, which means you’re more likely to acquire immunity without putting your life at risk.
So I’d encourage you think about questions like: After we practice explaining the mask-making process in our workshops, can we find a way to explain mask-making via radio / flyers / newspaper articles? Or can we tell everyone at our mask-making workshops that they should run their own mask-making workshops for their family and friends and so on, so the mask-making knowledge spreads through the population that way?
Additionally, from what I’ve read some homemade masks are much more effective than others. Some snippets from my notes on mask effectiveness:
https://www.nationalgeographic.com/science/2020/07/how-to-make-coronavirus-masks-that-everyone-will-want-to-wear-cvd/
https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronavirus/coronavirus-face-masks-what-you-need-to-know
https://www.sleepphones.com/Comfortable-Coronavirus-Face-Mask-Beard-Glasses-Fogging
https://www.nytimes.com/article/coronavirus-homemade-mask-material-DIY-face-mask-ppe.html
https://www.medrxiv.org/content/10.1101/2020.04.17.20069567v2.full.pdf
So it’s probably worth doing some research to figure out the best mask design from the perspective of effectiveness, ease of explaining how to create, and likelihood that people in the Santa Division will be able to acquire the necessary materials, if you haven’t already done this.
Hi John,
This is so cool! Actually EA Cameroon has done this research and they recommended using socks. However, all the resources will specify that any fabric works, as long as it covers mouth and nose.
And yes, I should write an update. The mask-making will be explained via radio and also taught to community leaders who will then be able to run the workshops. It is actually a great idea to schedule these workshops. Everyone will be encouraged to share the general information regarding preventive measures.
Hm, socks are knitted not woven, right?
Yes. In terms of percentage, how less effective are 4 layers of woven fabric in preventing the spread of coronavirus than 4 layers of knitted fabric? Than 2 layers of woven fabric? The idea is to have at least 4 layers of the sock (after folding) or at least 2 layers of other fabric. In preventing breathing in the virus?
I have no idea, I already shared my notes above! :) Perhaps the team could reach out to e.g. the author of the Johns Hopkins article?
BTW, I did find this article which argues for knitted masks:
https://stringking.com/face-masks/knit-vs-woven-fabric/
However, I’m more inclined to trust Johns Hopkins. But maybe the author of the Johns Hopkins article would have interesting opinions on the above link.
Edit: Here’s more info
https://med.stanford.edu/news/all-news/2020/06/stanford-scientists-contribute-to-who-mask-guidelines.html
OK, thank you. Added that better fitting masks made of denser material work better.