Medical Masks Similar to N95 Respirators for Preventing COVID-19

Masked woman behind partition signing form.
Masked woman behind partition signing form.
No significant difference seen with medical masks versus N95 respirators for health care personnel providing care to COVID-19 patients

HealthDay News — For health care workers providing care to patients with COVID-19, the risk for COVID-19 does not differ significantly with use of medical masks vs N95 respirators, according to a study published online November 29 in the Annals of Internal Medicine.

Mark Loeb, MD, from McMaster University in Hamilton, Ontario, Canada, and colleagues examined whether medical masks are noninferior to N95 respirators for preventing COVID-19 in health care workers providing routine care in a multicenter trial. Data were included for 1009 health care workers at 29 health care 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% of participants in the medical mask and N95 respirator groups, respectively (hazard ratio [HR], 1.14; 95% CI, 0.77 to 1.69). In a subgroup analysis by country, RT-PCR-confirmed COVID-19 occurred in 6.11 and 2.22% of the medical mask vs N95 respirator groups in Canada, respectively (HR, 2.83; 95% CI, 0.75 to 10.72); in 35.29 vs 23.53% in Israel (HR, 1.54; 95% CI, 0.43 to 5.49); in 3.26 vs 2.13% in Pakistan (HR, 1.50; 95% CI, 0.25 to 8.98); and in 13.62 vs 14.56% in Egypt (HR, 0.95; 95% CI, 0.60 to 1.50).

“Among health care 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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