Effectiveness of Face Mask or Respirator Use in Indoor Public Settings for Prevention of SARS-CoV-2 Infection — California, February–December 2021
cdc.gov Weekly / February 11, 2022 / 71(6);212–216
On February 4, 2022, this report was posted online as an MMWR Early Release.
Kristin L. Andrejko1,2,*; Jake M. Pry, PhD2,*; Jennifer F. Myers, MPH2; Nozomi Fukui2; Jennifer L. DeGuzman, MPH2; John Openshaw, MD2; James P. Watt, MD2; Joseph A. Lewnard, PhD1,3,4; Seema Jain, MD2; California COVID-19 Case-Control Study Team (View author affiliations)
“Consistent use of a face mask or respirator in indoor public settings was associated with lower odds of a positive SARS-CoV-2 test result (adjusted odds ratio = 0.44). Use of respirators with higher filtration capacity was associated with the most protection, compared with no mask use.”
“Rail deregulation led to consolidation, price-gouging, and a variant of just-in-time unloading that left no slack in the system”