Mask Studies and Articles
Possible Negative Studies
Impact of non-pharmaceutical interventions against COVID-19 in Europe: a quasi-experimental study
https://www.medrxiv.org/content/10.1101/2020.05.01.20088260v1.full.pdf
A cluster randomised trial of cloth masks compared with medical masks in healthcare workers
https://bmjopen.bmj.com/content/5/4/e006577
Mouth-nose protection in public: No evidence of effectiveness
https://www.thieme-connect.com/products/ejournals/html/10.1055/a-1174-6591
Little or No Efficacy Studies
Analysis of the Effects of COVID-19 Mask Mandates on Hospital Resource Consumption and Mortality at the County Level Noteworthy: “There was no reduction in per-population daily mortality, hospital bed, ICU bed, or ventilator occupancy of COVID-19-positive patients attributable to the implementation of a mask-wearing mandate.”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8395971/
https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article
https://www.acpjournals.org/doi/10.7326/M20-6817
COMMENTARY: Masks-for-all for COVID-19 not based on sound data
https://www.cidrap.umn.edu/news-perspective/2020/04/commentary-masks-all-covid-19-not-based-sound-data
Universal Masking in Hospitals in the Covid-19 Era
https://www.nejm.org/doi/full/10.1056/NEJMp2006372
https://www.medrxiv.org/content/10.1101/2020.04.01.20049528v1
Marginally Positive Studies
The Impact of Community Masking on COVID-19: A Cluster-Randomized Trial in Bangladesh
Noteworthy: “The proportion of individuals with COVID-like symptoms was 7.62% (N=13,273) in the intervention arm and 8.62% (N=13,893) in the control arm”
https://www.poverty-action.org/sites/default/files/publications/Mask_RCT____Symptomatic_Seropositivity_083121.pdf
Noteworthy: “The results show that a standard surgical and three-ply cloth masks, which see current widespread use, filter at apparent efficiencies of only 12.4% and 9.8%, respectively. Apparent efficiencies of 46.3% and 60.2% are found for KN95 and R95 masks”
https://aip.scitation.org/doi/10.1063/5.0057100
Significantly Positive Studies