Medical Masks vs N95 Respirators for COVID-19
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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
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Condition or disease | Intervention/treatment | Phase |
---|---|---|
Coronavirus N95 Medical Mask | Device: Medical Mask Device: N95 respirator | Phase 4 |

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 |

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 |
- RT-PCR confirmed COVID-19 infection [ Time Frame: 10 weeks ]Number of participants with RT-PCR confirmed COVID-19 infection
- Acute respiratory illness [ Time Frame: 10 weeks ]Number of participants with acute respiratory illness
- Absenteeism [ Time Frame: 10 weeks ]Number of participants with absenteeism
- Lower respiratory infection [ Time Frame: 10 weeks ]Number of participants with lower respiratory infection
- Pneumonia [ Time Frame: 10 weeks ]Number of participants with pneumonia
- ICU admission [ Time Frame: 10 weeks ]Number of participants with ICU admission
- Mechanical ventilation [ Time Frame: 10 weeks ]Number of participants needing mechanical ventilation
- Death [ Time Frame: 10 weeks ]Number of participants that died

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.
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.

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
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 | |
Egypt | |
Fayoum General Hospital | |
Fayoum, Egypt | |
Israel | |
Golden Care LTCF | |
Tzrifin, Israel | |
Pakistan | |
Dr. Ziauddin Hospital | |
Karachi, Pakistan |
Principal Investigator: | Mark B Loeb | McMaster University |
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 |
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 |
Coronavirus Infections Coronaviridae Infections Nidovirales Infections |
RNA Virus Infections Virus Diseases Infections |