I posted this before but posting for those who are asking about masks.
https://pubmed.ncbi.nlm.nih.gov/32355904/
To Mask or Not to Mask: Modeling the Potential for Face Mask Use by the General Public to Curtail the COVID-19 Pandemic
Notably, masks are found to be useful with respect to both preventing illness in healthy persons and preventing asymptomatic transmission. Hypothetical mask adoption scenarios, for Washington and New York state, suggest that immediate near universal (80%) adoption of moderately (50%) effective masks could prevent on the order of 17-45% of projected deaths over two months in New York, while decreasing the peak daily death rate by 34-58%, absent other changes in epidemic dynamics. Even very weak masks (20% effective) can still be useful if the underlying transmission rate is relatively low or decreasing: In Washington, where baseline transmission is much less intense, 80% adoption of such masks could reduce mortality by 24-65% (and peak deaths 15-69%), compared to 2-9% mortality reduction in New York (peak death reduction 9-18%). Our results suggest use of face masks by the general public is potentially of high value in curtailing community transmission and the burden of the pandemic. The community-wide benefits are likely to be greatest when face masks are used in conjunction with other non-pharmaceutical practices (such as social-distancing), and when adoption is nearly universal (nation-wide) and compliance is high.
https://www.tampabay.com/news/health/2020/05/19/politifact-face-masks-including-homemade-ones-are-effective-covid-19-protection-experts-say/
“While evidence is still very limited, several laboratory studies indicate that the majority of homemade mask materials, including cotton fabric, cotton T-shirts, tea cloth, flannel, silk, linen, scarves, and chiffon offer at least 50 percent protection. Higher quality, more tightly woven fabrics are better, and multiple layers improves protection.”
‘Howard says that researchers were looking at the wrong question at first — how well a mask protects the wearer from infection — and not how well a mask prevents an infected person from spreading the virus. He said masks function very differently as personal protective equipment versus “source control.”’
'“When a person expels droplets into the air, they quickly evaporate and shrink to become tiny airborne particles called droplet nuclei. These are extremely hard to remove from the air. However, in the moist atmosphere between a person’s mouth and their mask, it takes nearly a hundred times as long for a droplet to evaporate and shrink into a droplet nuclei.”
He continued: “This means that nearly any kind of simple cloth mask is great for source control. The mask creates humidity, this humidity prevents virus-containing droplets from turning into droplet nuclei, and this allows the fabric of the mask to block the droplets.”’
