Association Between Implementation of a Universal Face Mask Policy for Healthcare Workers in a Health Care System and SARS-CoV-2 Positivity Testing Rate in Healthcare Workers. - Wang DD; O'Neill WW; Zervos MJ; McKinnon JE; Allard D; Alangaden GJ; Schultz LR; Poisson LM; Chu BS; Kalkanis SN; Suleyman G (Journal of occupational and environmental medicine, 2021)