One more fly in the ointment of the Bangladesh study, not considered by Prof Fenton: assuming (valid or not) that all mask wearers in the villages in the test study actually wore their masks unfailingly, it has been shown by other studies that the psychological effects of mask-wearing induce alarm in other people which causes them to instinctively distance themselves from the mask-wearer. As a confounder, it is possible that this may be the dominant factor which produced the modest results of the study, since physical distancing (various) has been shown to be effective in preventing spread. The same or much more significant results may then have been produced by everyone wearing signs around their neck proclaiming "Stay Away!" or hearkening back to much earlier times, "Unclean!" https://brownstone.org/articles/the-point-of-masks-to-cause-alarm/