Which studies are you referring to? Most studies I see and read show non-medical cloth masks (store bought and homemade) are ineffective or don't draw a conclusion. There is one study I can post later tonight where they mixed material and it was very effective as long as there was no gap. A gap between the skin and mask can reduce its effectiveness significantly.Clearly, there have always been poor studies. Sometimes it takes decades to be corrected. In this case, the studies were called out in days. The good news is that the preponderance of work is showing that masks and social distancing are the quickest, cheapest, and easiest means for individuals to protect others, and themselves, while still offering some hope of restarting our economies. More high tech measures are in the works, but still many months away.
A report on masks relied on unfounded assumptions, researchers charged, and the authors were permitted to choose their own reviewers.www.nytimes.com