Medical Masks Similar to N95 Respirators for Preventing COVID-19

For healthcare workers providing care to patients with COVID-19, the risk for COVID-19 does not differ significantly with the use of medical masks versus N95 respirators, according to a study published online Nov. 29 in the Annals of Internal Medicine.

Mark Loeb, M.D., from McMaster University in Hamilton, Ontario, Canada, and colleagues examined whether medical masks are non-inferior to N95 respirators for preventing COVID-19 in healthcare workers providing routine care in a multicenter trial. Data were included for 1,009 healthcare workers at 29 healthcare facilities who provided direct care to patients with suspected or confirmed COVID-19 and used medical masks or fit-tested N95 respirators for 10 weeks.

The researchers found that in the intention-to-treat analysis, reverse transcriptase polymerase chain reaction (RT-PCR)-confirmed COVID-19 occurred in 10.46 and 9.27 percent of participants in the medical mask and N95 respirator groups, respectively (hazard ratio [HR], 1.14; 95 percent confidence interval [CI], 0.77 to 1.69). In a subgroup analysis by country, RT-PCR-confirmed COVID-19 occurred in 6.11 and 2.22 percent of the medical mask versus N95 respirator groups in Canada, respectively (HR, 2.83; 95 percent CI, 0.75 to 10.72); in 35.29 versus 23.53 percent in Israel (HR, 1.54; 95 percent CI, 0.43 to 5.49); in 3.26 versus 2.13 percent in Pakistan (HR, 1.50; 95 percent CI, 0.25 to 8.98); and in 13.62 versus 14.56 percent in Egypt (HR, 0.95; 95 percent CI, 0.60 to 1.50).

“Among healthcare workers who took care of patients with suspected or confirmed COVID-19, although the upper limit of the CIs of the pooled estimate for medical masks, when compared with N95 respirators for preventing RT-PCR-confirmed COVID-19, was within the noninferiority margin of 2, this margin was wide, and firm conclusions about noninferiority may not be applicable given the between-country heterogeneity,” the authors write.

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