Effectiveness of N95 respirators versus surgical masks against influenza: a systematic review and meta-analysis
Open accessAbstract
Objective: Previous meta‐analyses concluded that there was insufficient evidence to determine the effect of N95 respirators. We aimed to assess the effectiveness of N95 respirators versus surgical masks for prevention of influenza by collecting randomized controlled trials (RCTs). Methods: We searched PubMed, EMbase and The Cochrane Library from the inception to January 27, 2020 to identify relevant systematic reviews. The RCTs included in systematic reviews were identified. Then we searched the latest published RCTs from the above three databases and searched ClinicalTrials.gov for unpublished RCTs. Two reviewers independently extracted the data and assessed risk of bias. Meta‐analyses were conducted to calculate pooled estimates by using RevMan 5.3 software. Results: A total of six RCTs involving 9 171 participants were included. There were no statistically significant differences in preventing laboratory‐confirmed influenza (RR = 1.09, 95% CI 0.92‐1.28, P > .05), laboratory‐confirmed respiratory viral infections (RR = 0.89, 95% CI 0.70‐1.11), laboratory‐confirmed respiratory infection (RR = 0.74, 95% CI 0.42‐1.29) and influenzalike illness (RR = 0.61, 95% CI 0.33‐1.14) using N95 respirators and surgical masks. Meta‐analysis indicated a protective effect of N95 respirators against laboratory‐confirmed bacterial colonization (RR = 0.58, 95% CI 0.43‐0.78). Conclusion: The use of N95 respirators compared with surgical masks is not associated with a lower risk of laboratory‐confirmed influenza. It suggests that N95 respirators should not be recommended for general public and nonhigh‐risk medical staff those are not in close contact with influenza patients or suspected patients.
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The authors of Long 2020 do not report a rationale for the exclusion in the sensitivity analysis, and do not report on exclusion of the studies with low weighting.
“The authors do not report a rationale for the exclusion in the sensitivity analysis, and do not report on exclusion of the studies with low weighting, which arguably would be more relevant in a sensitivity analysis.”
From Physical interventions to interrupt or reduce the spread of respiratory viruses (2023) · cites this paper as Long 2020
Section 2.5 (Data analysis; page not provided) gives a rationale for the sensitivity analysis: testing robustness by excluding individual studies from each forest plot. Section 3.3 (Effectiveness; page not provided) reports results after excluding each trial for some outcomes, but does not separately report a sensitivity analysis focused on low-weight studies. Thus, the claim that no rationale is reported is overstated, while the narrower point about low-weight-focused reporting is supported. (LLM, conf=0.83)
Experimental — accuracy not yet measuredLong 2020 found no difference between N95/P2 respirators and medical/surgical masks for either influenza (RR 1.09, 95% CI 0.92 to 1.28) or respiratory viral infections (RR 0.89, 95% CI 0.70 to 1.11).
“A recent meta‐analysis included five trials comparing N95/P2 respirators with medical/surgical masks and found no difference between groups for either influenza (RR 1.09, 95% CI 0.92 to 1.28), or respiratory viral infections (RR 0.89, 95% CI 0.70 to 1.11) (Long 2020).”
From Physical interventions to interrupt or reduce the spread of respiratory viruses (2023) · cites this paper as Long 2020
Section 3.3 reports both risk ratios and finds no statistically significant difference for either outcome. But the paper included six RCTs overall, not five: five reported laboratory-confirmed influenza, while four reported respiratory viral infections (Abstract; §3.3). (LLM, conf=0.88)
Experimental — accuracy not yet measuredBy excluding Loeb 2009, Long 2020 reported a significant protective effect against viral infections (RR 0.61, 95% CI 0.39 to 0.98).
“By excluding Loeb 2009 (an open, non‐inferiority RCT that compared medical/surgical masks with N95 respirators in protecting HCWs against influenza), the authors reported a significant protective effect against viral infections (RR 0.61, 95% CI 0.39 to 0.98).”
From Physical interventions to interrupt or reduce the spread of respiratory viruses (2023) · cites this paper as Long 2020
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- Authors
- Long, Y., Hu, T., Liu, L., Chen, R., Guo, Q., Yang, L., Cheng, Y., Huang, J., & Du, L.
- Affiliations
- Sichuan University (CN)
- Chengdu University of Traditional Chinese Medicine (CN)
- Chinese Evidence‐Based Medicine Center West China Hospital Sichuan University Chengdu P.R. China
- Corresponding author
- Huang, Jin
- Du, Liang
- Venue
- Journal of Evidence-Based Medicine
- Publisher
- Wiley
- Published
- 2020-03-13
- Volume
- 13
- Issue
- 2
- Pages
- 93-101
- ISSN
- 1756-5383 (ISSN-L)
- 1756-5391
- PMC
- PMC7228345
- OpenAlex
- W3011632109
- Cited by
- 339
- References
- 40
- Citations by year
- 2026: 4 · 2025: 5 · 2024: 15 · 2023: 41 · 2022: 42 · 2021: 81 · 2020: 150
- FWCI
- 11.00
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Journal of Evidence-Based Medicine (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Funders
- National Natural Science Foundation of China (81873197, 81403276)
- Topics
- Health Sciences › Medicine › Pulmonary and Respiratory Medicine › Infection Control and Ventilation
- Health Sciences › Medicine › Epidemiology › Influenza Virus Research Studies
- Health Sciences › Medicine › Epidemiology › Respiratory viral infections research
- Keywords
- N95 respirators, surgical masks, influenza prevention, respiratory protection, laboratory-confirmed influenza, respiratory viral infections, bacterial colonization, mask effectiveness
- MeSH terms
- Humans, Influenza, Human, Masks, Respiratory Protective Devices, Randomized Controlled Trials as Topic
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