While paddling down the river of Confirmation Bias recently (the bugs were bad, take some spray!) I read an article from the CDC’s Journal of Emerging Infectious Diseases: Nonpharmaceutical Measures for Pandemic Influenza in Nonhealthcare Settings—Personal Protective and Environmental Measures. There was some stuff about a handwashing study in Egypt, and some commentary on surface and object cleaning in daycare nurseries (entry into the latter which would justify full HAZMAT and scrub-down protocols).
But the interesting part was the meta-analysis of facemask use from 1946-2018 in preventing influenza transmission (“One study evaluated the use of masks among pilgrims from Australia during the Hajj pilgrimage…” And y’all think I’m not practically applicable). Studies of the Australians, two different university settings, and a clutch of households showed no significant transmission risk between maskers and non-maskers. Of note: “Most studies were underpowered because of limited sample size, and some studies also reported suboptimal adherence in the face mask group.”
And then: “There is limited evidence for their effectiveness in preventing influenza virus transmission either when worn by the infected person for source control or when worn by uninfected persons to reduce exposure. Our systematic review found no significant effect of face masks on transmission of laboratory-confirmed influenza.”
So, place your bets. I just think it’s fun to include a point of view outside of the herd, and I still think that the sideline staffs and fans in the stands (25% occupancy!) bound up with masks look ridiculous.