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. 2020 Apr 4.
doi: 10.1111/irv.12745. Online ahead of print.

Medical Masks vs N95 Respirators for Preventing COVID-19 in Healthcare Workers: A Systematic Review and Meta-Analysis of Randomized Trials

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Medical Masks vs N95 Respirators for Preventing COVID-19 in Healthcare Workers: A Systematic Review and Meta-Analysis of Randomized Trials

Jessica J Bartoszko et al. Influenza Other Respir Viruses. .
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Background: Respiratory protective devices are critical in protecting against infection in healthcare workers at high risk of novel 2019 coronavirus disease (COVID-19); however, recommendations are conflicting and epidemiological data on their relative effectiveness against COVID-19 are limited.

Purpose: To compare medical masks to N95 respirators in preventing laboratory-confirmed viral infection and respiratory illness including coronavirus specifically in healthcare workers.

Data sources: MEDLINE, Embase, and CENTRAL from January 1, 2014, to March 9, 2020. Update of published search conducted from January 1, 1990, to December 9, 2014.

Study selection: Randomized controlled trials (RCTs) comparing the protective effect of medical masks to N95 respirators in healthcare workers.

Data extraction: Reviewer pair independently screened, extracted data, and assessed risk of bias and the certainty of the evidence.

Data synthesis: Four RCTs were meta-analyzed adjusting for clustering. Compared with N95 respirators; the use of medical masks did not increase laboratory-confirmed viral (including coronaviruses) respiratory infection (OR 1.06; 95% CI 0.90-1.25; I2 = 0%; low certainty in the evidence) or clinical respiratory illness (OR 1.49; 95% CI: 0.98-2.28; I2 = 78%; very low certainty in the evidence). Only one trial evaluated coronaviruses separately and found no difference between the two groups (P = .49).

Limitations: Indirectness and imprecision of available evidence.

Conclusions: Low certainty evidence suggests that medical masks and N95 respirators offer similar protection against viral respiratory infection including coronavirus in healthcare workers during non-aerosol-generating care. Preservation of N95 respirators for high-risk, aerosol-generating procedures in this pandemic should be considered when in short supply.

Keywords: COVID-19; N95 respirators; SARS-CoV-2; coronavirus; masks; meta-analysis; systematic review.

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    1. World Health Organization. WHO declares COVID-19 a pandemic. 2020. Accessed March 13, 2020.
    1. Johnston LB, Conly JM. Severe acute respiratory syndrome: What have we learned two years later? Can J Infect Dis Med Microbiol. 2004; 15(6): 309-312.
    1. Wang D, Hu B, Hu C et al Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in wuhan, China. JAMA. 2020;323(11):1061-1069.
    1. The Novel Coronavirus Pneumonia Emergency Response Epidemiology Team. The Epidemiological Characteristics of an Outbreak of 2019 Novel Coronavirus Diseases (COVID-19) - China, 2020[J]. China CDC Weekly. 2020;2(8):113-122.
    1. Centers for Disease Control and Prevention (CDC). COVID-19 transmission. 2020. Accessed March 15, 2020.

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