The PPE Pandemic: Sex-Related Discrepancies of N95 Mask Fit

Abstract

During the COVID-19 pandemic, caused by the severe acute respiratory syndrome coronavirus 2, healthcare professionals across the world have been at high risk of transmission because of their direct contact with infected patients. In October 2020, the International Council of Nurses (ICN) confirmed that 1,500 nurses had died from COVID-19 in 44 countries and estimated that healthcare worker COVID-19 fatalities worldwide could be more than 20,000. To ensure protection of healthcare personnel, properly fitting personal protective equipment (PPE) must be worn. In a ‘one size fits all’ world, the differences between the fit of PPE for men and women can have devastating consequences. An N95 respirator mask is a component of PPE outlined by the Centers for Disease Control and Prevention (CDC) for protection against COVID-19; however, N95 masks do not offer protection if they do not fit properly. Fit testing is performed to ensure an adequate seal of the mask on the wearer. A single-institution retrospective review was performed on fit testing results for male versus female wearers in an attempt to elucidate a difference in failure rates. Females failed at a significantly higher rate than their male counterparts (6.67% female, 2.72% male; p=0.001), and the reason reported was often due to being ‘small-boned’ (p<0.0001). Sex-related differences in proper PPE fit are not new; however, the COVID-19 pandemic has made the situation more acute, and sex-specific N95 mask designs must be developed quickly, as the pandemic shows little signs of abating.

A systematic review of passing fit testing of the masks and respirators used during the COVID-19 pandemic: Part 1-quantitative fit test procedures

“…Eight studies looked at the effect of gender on fitting ability [ 32 , 37 , 66 , 78 , 89 , 107 , 111 , 114 , 117 ], with four of these highlighting that males had a higher pass rate than females [ 66 , 89 , 111 , 117 ]. Christopher et al highlighted the reasons for failing the fit test for females, including facial asymmetry (8%), small bones (77%), and none reported (15%), and the reasons for males, including facial hair (91%), large bones (3%), and small bones (6%) [ 89 ]. In the study by Williams et al, although males had a higher passing rate than females; however, females were fitted with the 3M 9320A more often than males (7.3% vs. 1.5%, p< 0.001) [ 111 ].…”

“…Four studies concluded the negative effects of facial hair on fitting capability [ 38 , 89 , 115 , 139 ]. Another point is that the influence of facial hair on the fitting capability of surgical masks was less than that of the FFP3 respirators.…”

“…The lower FFs for the HCWs without facial hair while wearing surgical masks could be attributed to their cranial shape and facial anatomy [ 38 ]. Two factors, including small bone structure for females and facial hair for males, are considered to be the main challenges for fit test failure [ 89 ]. Subjects must be clean-shaven prior to fit testing and while donning a tight-fitting respirator; otherwise, positive pressure respirators (such as PAPR, etc.)…”

“…Eight studies looked at the effect of gender on fitting ability [32,37,66,78,89,107,111,114,117], with four of these highlighting that males had a higher pass rate than females [66,89,111,117]. Christopher et al highlighted the reasons for failing the fit test for females, including facial asymmetry (8%), small bones (77%), and none reported (15%), and the reasons for males, including facial hair (91%), large bones (3%), and small bones (6%) [89].…”