Medical Masks Versus N95 Respirators to Prevent 2019 Novel Coronavirus Disease (COVID-19) in Healthcare Workers: A Randomized Trial

A randomized controlled trial in which health care workers will be randomized to either medical masks or N95 respirators when providing medical care to patients with COVID-19. This multi-centre randomized controlled trial will assess whether medical masks are non-inferior to N95 respirators when health care workers provide care involving non-aerosol generating procedures. Health care workers will be randomized to either use of a medical mask or to a fit-tested N95 respirator when providing care for patients with febrile respiratory illness. Health care workers randomly assigned to the N95 respirator group will be instructed to use a fit-tested National Institute for Occupational Safety and Health-approved N95 respirator when providing routine care to patients with COVID-19 or suspected COVID-19. Participants will use the type of device they were allocated to, either a medical mask or an N95 respirator, for 10 weeks, however, health care workers can also use the N95 respirator at any time based on a point-of-care risk assessment. Universal masking is the policy implemented at each study site. Extended and re-use of N95 respirators will be permitted if the local situation requires it. The primary outcome is laboratory confirmed RT-PCR COVID-19 among participants.

A nasopharyngeal swab will be obtained if any one of the following symptoms or signs is present: fever (≥38 C), cough, or shortness of breath, or if 2 of the following are present: fatigue, myalgia, headache, dizziness, expectoration, sore throat, diarrhea, nausea, vomiting, abdominal pain, runny nose, altered taste or smell, conjunctivitis, or painful swallowing.

Participants that receive a COVID-19 vaccine after enrollment with efficacy of > 50% for the circulating strain will continue to be followed until 2 weeks after the first dose of the vaccine. All other participants will be followed for 10 weeks.

Self-reporting of hand hygiene and the use of external monitors, where feasible, will be used to collect basic hand hygiene data.

The sample size is 1,010 participants. This will allow 90% power at an alpha (one sided) of 0.05 and to account for participants who may not have completed 10 weeks because of COVID-19 mRNA vaccination.