[palmer]

Picking one from the list: "Smith, J.D. et al. (2016) "Effectiveness of N95 respirators versus surgical masks in protecting health care workers from acute respiratory infection: a systematic review and meta-analysis", CMAJ Mar 2016, cmaj.150835; DOI: 10.1503/cmaj.150835 "We identified 6 clinical studies ... In the meta-analysis of the clinical studies, we found no significant difference between N95 respirators and surgical masks in associated risk of (a) laboratory-confirmed respiratory infection, (b) influenza-like illness, or (c) reported work-place absenteeism."

Here's the paper: https://www.cmaj.ca/content/cmaj/188/8/567.full.pdf?fbclid=IwAR26rwHBupMrOwV5NZ4EZDrK_7rEy3HWeZ01Dpbu3diPle1zGM3h3IOPYM0 They are comparing surgical versus N95, not mask versus no mask. Presumably that study is included in the artcile because the surgical masks have gaps and are assume to be inferior, And of course practically every mask being worn in public these days is inferior to a fitted N95. But that doesn't answer the question of effectiveness.

[Grandpa Drudge]

You observe "But that doesn't answer the question of effectiveness." In a roundabout way, it does answer the question of effectiveness.

Other studies make it clear that surgical masks do not work against viruses. This paper indicates N95 respirators don't work significantly better. Neither are effective against viruses.