1/ Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers: A Randomized Controlled Trial
"95% confidence intervals are compatible w/ 46% reduction to 23% increase in infection."
acpjournals.org/doi/10.7326/m2…
2/ "During the study period (3 April to 2 June 2020), Danish authorities did not recommend masking. Use was uncommon (<5%) outside hospitals.
"Participants were randomly assigned to mask/control groups.
"Those in the mask group received 50 3-layer, disposable surgical masks."
3/ "Participants received follow-up surveys to collect information on antibody test results, adherence to recommendations on time spent outside the home, development of symptoms, COVID-19 diagnosis based on PCR testing done in public hospitals, and known COVID-19 exposures."
4/ "A recommendation to wear a surgical mask when outside the home among others did not reduce, at conventional levels of stat. significance, incident SARS-CoV-2 infection vs. no mask recommendation. We designed the study to detect a reduction in infection rate from 2% to 1%."
5/ "The findings, however, should not be used to conclude that a recommendation for everyone to wear masks in the community would not be effective in reducing SARS-CoV-2 infections, as the trial did not test the role of masks in source control of SARS-CoV-2 infection."
6/ "The face masks were high-quality surgical masks with a filtration rate of 98%.
"Face shields covering the eyes has been advocated to halt the conjunctival route of transmission, but we observed no stat. significant interaction between wearers & nonwearers of eyeglasses."
7/ "Practical challenges to implementation include potentially incorrect wearing, reduced adherence, reduced durability depending on type of mask & occupation, weather, physical & psychological discomfort, and changing to less cautious behavior due to a false sense of security."
8/ More:
Assessing mandatory stay‐at‐home and business closure effects on the spread of COVID‐19
Global Assessment of the Impact of Masking on COVID-19: A Country Level Comparative & Retrospective Analyses Using the Richards Model
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