Among healthcare workers, the use of N95 respirators was associated with fewer viral infectious episodes compared with the use of surgical masks, according to results of a meta-analysis published in the Journal of the American College of Emergency Physicians.
In this meta-analysis, investigators searched the PubMed, MEDLINE, and the Cochrane Library databases to identify studies which assessed the effectiveness of surgical masks vs N95 respirators in decreasing the risk for viral respiratory illness. They conducted the meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.
Overall, 8 studies including a total of 9164 participants were analyzed. Eligible participants included those with influenza virus infection, influenza-related illness, or other respiratory viral infections. In addition, studies that were conducted outside of healthcare settings were excluded from the analysis.
There were significant differences found between the effectiveness of N95 respirators vs surgical masks for the prevention of influenza-like-illness (risk ratio (RR), 0.81; 95% CI, 0.68-0.94; P <.05), noninfluenza respiratory viral infection (RR, 0.62; 95% CI, 0.52-0.74; P <.05), respiratory viral infection (RR, 0.73; 95% CI, 0.65-0.82; P <.05), SARS-CoV-1 and SARS-CoV-2 infections (RR, 0.17; 95% CI, 0.06-0.49; P <.05), and laboratory-confirmed respiratory viral infection (RR, 0.75; 95% CI, 0.66-0.84; P <.05). Of note, the results regarding the effectiveness of N95 respirators vs surgical masks for protection against laboratory-confirmed influenza virus infection were not statistically significant (RR, 0.87; 95% CI, 0.74-1.03; P >.05).
Study limitations included the risk of bias in the analyzed studies, heterogeneity across studies in terms of surgical mask type and types of viral infections assessed, and the lack of an assessment to determine the rate of adherence to masking.
The researchers concluded that “this meta-analysis highlights the necessity for more robust research to help guide institutional and national policies regarding [personal protective equipment] use during the COVID-19 pandemic and with other viral disease outbreaks in the future.”
Collins AP, Service BC, Gupta S, et al. N95 respirator and surgical mask effectiveness against respiratory viral illnesses in the healthcare setting: A systematic review and meta-analysis. J Am Coll Emerg Physicians Open. 2021;2(5):e12582. doi:10.1002/emp2.12582.