Medical grade masks such as N95 respirators may not fit female and Asian health care workers as well as their male, Caucasian counterparts, researchers in Australia reported Tuesday.
It’s an especially important question because of the coronavirus pandemic and the researchers recommend more consistent testing of masks for health care workers, rather than having each worker check the fit.
Britta von Ungern-Sternberg from the Perth Children’s Hospital and colleagues reviewed data and studies going back to 2003 on how well filtering facepiece respirators fit, and found the masks passed fit tests just 85% of the time for women, compared to 95% of the time for men.
They also found these rates were lower among Asians, (84%), than Caucasians, (90%). Fit test pass rates were particularly low in Asian females, with an average fit pass rate of 60%, they reported in the journal Anaesthesia. How well a mask fits is more important than the how well the material it is made of filters the air, the researchers said.
Health care workers are more likely than other people to become infected with coronavirus, the team noted. Inadequate personal protective equipment (PPE) is sometimes to blame, and poorly fitting masks and respirators can be a factor.
The US National Institute for Occupational Safety and Health standards requires N95 masks used in the US to meet a fit of 95%, defined by a fit test panel. The team notes that the dimensions of that test panel come from a group in which women and Asian people are underrepresented.
The researchers also compared mask “fit checks,” when a health care worker checks their own mask to make sure it’s fitting properly, to “fit tests,” which are more involved and costly but yield a more accurate assessment. Health care workers are supposed to check their masks every time they are used, but the researchers do not recommend replacing fit tests with fit checks.
Qualitative fit testing involves releasing sprays that test bitter or sweet test agents. If the mask-wearer cannot taste the bitter or sweet test agents, the mask is determined to fit. Quantitative fit testing involves actually measuring the concentration of substances inside and outside the mask to determine how well the mask fits and filters particles.
Source : CNN