First study relates to influenza, not Covid. Besides, the study is hardly of scientific quality, being based on ta flu' season events 17 years ago, involving a small sample of only 143 housholds and mask adherenece was self-reported, anyway:
Second study heavily caveated :
The third study focuses on multi-layer cloth masks and is essentially a summary a number of other small studies, many of which the difference was not statistically significant, many involved self-reporting and none of which were able to separate correlation from causation in a controlled setting (for example, one is a salon which was fully mask setting in which none of 67 patrons reported Covid after being in the salon... well, that's hardly conclusive; they could just as easily have not got Covid even if no one was wearing a mask in the salon. Besides, only 67 out of 137 patrons were tested, so the powering of that study is flimsy at best).
The fourth study specifically involved surgical masks and in fact, it concluded that cloth masks made no statistical difference:
(So you've posted something which merely serves to reinforce my cynicism about the effectiveness of masks. Did you even actually even read and digest the content of what you posted?)
