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Cited by 328Infection Control and VentilationInfection Control in HealthcareOccupational Health and Safety in Workplaces

Effectiveness of N95 respirators versus surgical masks in protecting health care workers from acute respiratory infection: a systematic review and meta-analysis

Open access
Smith, Jeffrey D., MacDougall, Colin C., Johnstone, Jennie, Copes, Ray A., Schwartz, Brian, Garber, Gary E.·2016·Canadian Medical Association Journal
DOI 10.1503/cmaj.150835PMC PMC4868605
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Abstract

BACKGROUND: Conflicting recommendations exist related to which facial protection should be used by health care workers to prevent transmission of acute respiratory infections, including pandemic influenza. We performed a systematic review of both clinical and surrogate exposure data comparing N95 respirators and surgical masks for the prevention of transmissible acute respiratory infections. METHODS: We searched various electronic databases and the grey literature for relevant studies published from January 1990 to December 2014. Randomized controlled trials (RCTs), cohort studies and case-control studies that included data on health care workers wearing N95 respirators and surgical masks to prevent acute respiratory infections were included in the meta-analysis. Surrogate exposure studies comparing N95 respirators and surgical masks using manikins or adult volunteers under simulated conditions were summarized separately. Outcomes from clinical studies were laboratory-confirmed respiratory infection, influenza-like illness and workplace absenteeism. Outcomes from surrogate exposure studies were filter penetration, face-seal leakage and total inward leakage. RESULTS: We identified 6 clinical studies (3 RCTs, 1 cohort study and 2 case-control studies) and 23 surrogate exposure studies. In the meta-analysis of the clinical studies, we found no significant difference between N95 respirators and surgical masks in associated risk of (a) laboratory-confirmed respiratory infection (RCTs: odds ratio [OR] 0.89, 95% confidence interval [CI] 0.64-1.24; cohort study: OR 0.43, 95% CI 0.03-6.41; case-control studies: OR 0.91, 95% CI 0.25-3.36); (b) influenza-like illness (RCTs: OR 0.51, 95% CI 0.19-1.41); or (c) reported workplace absenteeism (RCT: OR 0.92, 95% CI 0.57-1.50). In the surrogate exposure studies, N95 respirators were associated with less filter penetration, less face-seal leakage and less total inward leakage under laboratory experimental conditions, compared with surgical masks. INTERPRETATION: Although N95 respirators appeared to have a protective advantage over surgical masks in laboratory settings, our meta-analysis showed that there were insufficient data to determine definitively whether N95 respirators are superior to surgical masks in protecting health care workers against transmissible acute respiratory infections in clinical settings.

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  • N95 FFRs have shown less filter penetration, fewer face seal leaks, and less total inward leakage than surgical masks under laboratory conditions.

    “N95 FFRs have shown less filter penetration, fewer face seal leaks, and less total inward leakage than surgical masks under laboratory conditions (Lee et al., 2008;Grinshpun et al., 2009;Smith et al., 2016)”

    From Size-selective Assessment of Respirator Protection against Airborne Fungi and (1→3)-β-D-glucan in Farms (2018) · cites this paper as Smith et al., 2016

  • Smith 2016 pooled three trials and found no difference for laboratory-confirmed respiratory infections (OR 0.89, 95% CI 0.64 to 1.24) or influenza-like illness (OR 0.51, 95% CI 0.19 to 1.41).

    “In a meta‐analysis comparing surgical masks with N95 respirators, Smith 2016 pooled three trials and found an estimate of effect suggesting no difference for laboratory‐confirmed respiratory infections (OR 0.89, 95% CI 0.64 to 1.24) or ILI (OR 0.51, 95% CI 0.19 to 1.41) (Loeb 2009; MacIntyre 2011; MacIntyre 2013).”

    From Physical interventions to interrupt or reduce the spread of respiratory viruses (2023) · cites this paper as Smith 2016

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Research works printed but not linked: 1

  1. Higgins JPT, Green S, editors. Cochrane handbook for systematic reviews of interventions, version 5.1.0. Oxford (UK): Cochrane Collaboration; 2011. Available: handbook.cochrane.org/ (accessed 2014 Jan. 26).

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Authors
Smith, J. D., MacDougall, C. C., Johnstone, J., Copes, R. A., Schwartz, B., & Garber, G. E.
Affiliations
University of Ottawa (CA)
ORCID
Venue
Canadian Medical Association Journal
Publisher
CMA Impact Inc.
Published
2016-03-07
Volume
188
Issue
8
Pages
567-574
ISSN
  • 0820-3946 (ISSN-L)
  • 1488-2329
DOI
10.1503/cmaj.150835
PMC
PMC4868605
OpenAlex
W2293429114
Cited by
328
References
61
Citations by year
2026: 3 · 2025: 5 · 2024: 15 · 2023: 28 · 2022: 31 · 2021: 74 · 2020: 150 · 2019: 13 · 2018: 4 · 2017: 4 · 2016: 1
FWCI
1.27
Type
journal article
Language
en
Open access
Locations
  • Canadian Medical Association Journal (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Health Sciences › Medicine › Pulmonary and Respiratory Medicine › Infection Control and Ventilation
  • Health Sciences › Medicine › Infectious Diseases › Infection Control in Healthcare
  • Health Sciences › Health Professions › Occupational Therapy › Occupational Health and Safety in Workplaces
Keywords
N95 respirators, surgical masks, healthcare workers, acute respiratory infections, pandemic influenza, respiratory protection, face masks, influenza-like illness, absenteeism, filter penetration, infection control
MeSH terms
Cross Infection, Humans, Masks, Occupational Diseases, Respiratory Protective Devices, Respiratory Tract Infections, Occupational Exposure

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