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Medical Masks vs N95 Respirators for COVID-19

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT04296643
Recruitment Status : Completed
First Posted : March 5, 2020
Last Update Posted : January 12, 2023
University of Alberta
Information provided by (Responsible Party):
McMaster University

Brief Summary:
A randomized controlled trial in which health care workers will be randomized to either medical masks or N95 respirators when providing care to patients with COVID-19.

Condition or disease Intervention/treatment Phase
Coronavirus N95 Medical Mask Device: Medical Mask Device: N95 respirator Phase 4

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 1009 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Intervention Model Description: pragmatic, randomized, open-label, multicentre, noninferiority trial.
Masking: Double (Investigator, Outcomes Assessor)
Masking Description: Investigators and laboratory assessors were blinded to the group assignment, but it was not possible to conceal the identity of the medical mask or N95 respirator assignment to the study staff or participants.
Primary Purpose: Prevention
Official Title: Medical Masks Versus N95 Respirators to Prevent 2019 Novel Coronavirus Disease (COVID-19) in Healthcare Workers: A Randomized Trial
Actual Study Start Date : March 1, 2020
Actual Primary Completion Date : June 1, 2022
Actual Study Completion Date : December 8, 2022

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: Medical Mask
Medical Mask worn when providing care to patient with febrile respiratory illness
Device: Medical Mask
Medical Mask (known also as Surgical Mask)

Active Comparator: N95 respirator
N95 respirator worn when providing care to patient with febrile respiratory illness
Device: N95 respirator
N95 respirator

Primary Outcome Measures :
  1. RT-PCR confirmed COVID-19 infection [ Time Frame: 10 weeks ]
    Number of participants with RT-PCR confirmed COVID-19 infection

Secondary Outcome Measures :
  1. Acute respiratory illness [ Time Frame: 10 weeks ]
    Number of participants with acute respiratory illness

  2. Absenteeism [ Time Frame: 10 weeks ]
    Number of participants with absenteeism

  3. Lower respiratory infection [ Time Frame: 10 weeks ]
    Number of participants with lower respiratory infection

  4. Pneumonia [ Time Frame: 10 weeks ]
    Number of participants with pneumonia

  5. ICU admission [ Time Frame: 10 weeks ]
    Number of participants with ICU admission

  6. Mechanical ventilation [ Time Frame: 10 weeks ]
    Number of participants needing mechanical ventilation

  7. Death [ Time Frame: 10 weeks ]
    Number of participants that died

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Health care workers who provide direct care to patients with suspected or confirmed COVID-19 in specialized COVID-19 units and in emergency departments, medical units, pediatric units, and long-term care facilities
  • Health care workers are required to spend 60% or more of their time doing clinical work when enrolled.

Exclusion Criteria:

  • Unable to pass or do not have a valid fit test within the past 24 months
  • One or more high-risk comorbidities for COVID-19 (hypertension, cardiac disease, pulmonary disease, chronic kidney disease, diabetes, chronic liver disease, actively treated cancer, or immunosuppression due to illness or medications)
  • Previous laboratory confirmed clinical diagnosis of COVID-19 at the time of
  • Received 1 or more doses of a COVID-19 vaccine with greater than 50% efficacy for the circulating strain (for example, mRNA or vector-based COVID-19 vaccine against the original SARS-CoV-2 strain).
  • working in intensive care units.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04296643

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Canada, Alberta
Foothills Medical Centre
Calgary, Alberta, Canada, T2N 1N4
University of Alberta Hospital
Edmonton, Alberta, Canada
Canada, Ontario
Brantford General Hospital
Brantford, Ontario, Canada
Hamilton Health Sciences
Hamilton, Ontario, Canada
St. Joseph's Healthcare
Hamilton, Ontario, Canada
Ottawa Hospital
Ottawa, Ontario, Canada, K1H 8L6
Hopital Montfort
Ottawa, Ontario, Canada, K1K 0T2
Niagara Health Services
St. Catherines, Ontario, Canada
St. Joe's Unity Health
Toronto, Ontario, Canada
St. Mike's Unity Health
Toronto, Ontario, Canada
Canada, Quebec
Montreal University Health Centre
Montréal, Quebec, Canada
The Jewish General Hospital
Montréal, Quebec, Canada
Fayoum General Hospital
Fayoum, Egypt
Golden Care LTCF
Tzrifin, Israel
Dr. Ziauddin Hospital
Karachi, Pakistan
Sponsors and Collaborators
McMaster University
University of Alberta
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Principal Investigator: Mark B Loeb McMaster University
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
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Responsible Party: McMaster University
ClinicalTrials.gov Identifier: NCT04296643    
Other Study ID Numbers: 20006014
First Posted: March 5, 2020    Key Record Dates
Last Update Posted: January 12, 2023
Last Verified: January 2023

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: No
Additional relevant MeSH terms:
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Coronavirus Infections
Coronaviridae Infections
Nidovirales Infections
RNA Virus Infections
Virus Diseases