It doesn’t seem like it, according to the Cochrane review: “Wearing masks in the community probably makes little or no difference to the outcome of laboratory-confirmed influenza/SARS-CoV-2 compared to not wearing masks.”
Some observers have taken this as a final, authoritative conclusion on the matter, an opinion shared by the man behind the review. “There is just no evidence that they make any difference. Full stop,” Tom Jefferson, the study’s lead author, said in an interview. Even fitted N95 masks in health care settings, the interviewer asked? “It makes no difference — none of it.”