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Randomized Control Trial to Study the Efficacy of the Surgical Mask Versus the N95 Respirator to Prevent Influenza

This study has been completed.
Health Canada
Information provided by:
McMaster University Identifier:
First received: September 19, 2008
Last updated: July 15, 2009
Last verified: July 2009
The goal of this study is to compare the efficacy of the surgical mask to the N95 respirator in protecting nurses from influenza in the hospital setting. The investigators propose a non-inferiority randomized controlled trial whereby nurses are randomized to either a surgical mask or an N95 respirator when caring for patients with febrile respiratory illness during the influenza season. The hypothesis is that the surgical mask offers similar protection against influenza to that of the N95. The specific objective of the study is to assess whether the rates of influenza (laboratory-confirmed by PCR and HAI assay), as well as secondary outcomes (influenza-like illness, work-related absenteeism, physician visits for respiratory illness, and lower respiratory infection), are similar among nurses using a surgical mask compared to those using an N95 respirator.

Condition Intervention
Influenza Device: Surgical mask Device: N95 mask

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Prevention
Official Title: A Randomized Control Trial of Surgical Masks vs N95 Respirators to Prevent Influenza in Health Care Workers

Resource links provided by NLM:

Further study details as provided by McMaster University:

Primary Outcome Measures:
  • Laboratory-confirmed Influenza Infection [ Time Frame: one year ]

Secondary Outcome Measures:
  • Physician Visits for Respiratory Illness [ Time Frame: one year ]
  • Influenza-like Illness [ Time Frame: Over entire study period ]
  • Absenteeism [ Time Frame: over study period ]

Enrollment: 447
Study Start Date: October 2008
Study Completion Date: May 2009
Primary Completion Date: April 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: 1. Surgical
surgical mask
Device: Surgical mask
Surgical mask worn for patients with febrile respiratory illness
Active Comparator: 2. N95 Respirator
N95 respirator
Device: N95 mask
N95 mask worn for patients with febrile respiratory illness


Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Nurses who work in emergency departments and medical units
  • Nurses expected to work full time (defined as > 37 hours per week)

Exclusion Criteria:

  • Nurses who were not fit tested
  • Nurses who could not pass a fit test
  Contacts and Locations
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, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00756574

Canada, Ontario
Hamilton Health Science
Hamilton, Ontario, Canada
Sponsors and Collaborators
McMaster University
Health Canada
Principal Investigator: Mark Loeb, MD, MSc Hamilton Health Sciences - McMaster University
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Dr. Mark Loeb, Department of Pathology and Molecular Medicine, McMaster University, Hamilton ON Identifier: NCT00756574     History of Changes
Other Study ID Numbers: 6273-15-2008
Study First Received: September 19, 2008
Results First Received: July 15, 2009
Last Updated: July 15, 2009

Keywords provided by McMaster University:

Additional relevant MeSH terms:
Influenza, Human
Orthomyxoviridae Infections
RNA Virus Infections
Virus Diseases
Respiratory Tract Infections
Respiratory Tract Diseases processed this record on September 21, 2017