Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021

This report describes experiments conducted by CDC to assess two ways of improving the fit of medical procedure masks.

Masking during the COVID-19 pandemic – An update of the evidence, National Collaborating Centre for Environmental Health

Performance Comparison of Single and Double Masks: Filtration Efficiencies, Breathing Resistance and CO2 Content

Face masks during the COVID-19 pandemic - Wikipedia

Federal Register :: COVID-19 Vaccination and Testing; Emergency

Adverse Effects of COVID-19 and Face Masks: A Systematic Review, JCAD

The Ultra fit community mask—Toward maximal respiratory protection via personalized face fit

Science Review: January 30 - February 17, 2021 - Prevent Epidemics

Outward and inward protections of different mask designs for different respiratory activities

Safety & Efficacy of Masks & Face Coverings During Exercise

COVID-19 false dichotomies and a comprehensive review of the evidence regarding public health, COVID-19 symptomatology, SARS-CoV-2 transmission, mask wearing, and reinfection, BMC Infectious Diseases

PDF) Outward and inward protection efficiencies of different mask designs for different respiratory activities

CDC: Double Masking Can Reduce COVID-19 Spread by up to 96.4%