Evaluation of Cloth Masks and Modified Procedure Masks as Personal Protective Equipment for the Public During the COVID-19 Pandemic

Evaluation of Cloth Masks and Modified Procedure Masks as Personal Protective Equipment This comparative study examines the fitted filtration efficiency of 7 consumer-grade face masks and 5 medical procedure mask modifications. JAMAInternalMed

Findings  In this comparative study of face covering FFEs, we observed that consumer-grade masks and improvised face coverings varied widely, ranging from 26.5% to 79.0% FFE. Modifications intended to enhance the fit of medical procedure masks improved FFE measurements from 38.5% (unmodified mask) to as much as 80.2%.

Meaning  Simple modifications can improve the fit and filtration efficiency of medical procedure masks; however, the practical effectiveness of consumer-grade masks available to the public is, in many cases, comparable with or better than their non-N95 respirator medical mask counterparts. ...

Masks serve a dual purpose to protect the wearer and others. These analyses were designed to quantify the protection that masks offer to the wearer when exposed to others who may be infected. The exact FFE required to prevent respiratory virus transmission is not precisely known. However, evidence from previous studies suggests that even face masks with an FFE less than 95% (eg, surgical masks) are effective in preventing the acquisition of epidemic coronaviruses (SARS-CoV-1, SARS-CoV-2) by health care clinicians, except possibly during aerosol-generating procedures.^6-8 For prevention of an associated coronavirus, SARS-CoV-1, N95 respirators had no increased prevention benefit over surgical masks.⁷

In this article, we reported that simple modifications to improve medical mask fit can substantially improve filtration efficiency. However, when FFE is considered (combined fit and material filtration), we demonstrated the practical effectiveness of consumer-grade masks to be, in many cases, nearly equivalent to or better than their nonrespirator medical mask counterparts. ...