N95 respirators and surgical masks for preventing transmission of respiratory infections to healthcare workers

Citation:  Offeddu V, Yung CF, Low MSF, et al. Effectiveness of masks and respirators against respiratory infections in healthcare workers: a systematic review and meta-analysis. Clinical Infectious Diseases 2017; 65(11): 1934-42

Citation: Long Y, Hu T, Liu L, et al. Effectiveness of N95 respirators versus surgical masks against influenza: A systematic review and meta-analysis. Journal of Evidence Based Medicine 2020 [Epub ahead of print: 13 March 2020]

Citation: Mukerji S, MacIntyre CR, Newall AT. Review of economic evaluations of mask and respirator use for protection against respiratory infection transmission. BMC Infectious Diseases 2015; 15: 413

What is this? Masks are worn to try to prevent the transmission of respiratory viruses and several systematic reviews have assessed the effects of healthcare workers wearing them.

Offeddu et al. examined the effects of respiratory personal protective equipment. They did not restrict their search by date or language of publication, and did it in November 2015. They identified 6 randomized trials (and included data from 5 of these); and 8 case-control studies and 4 cohort studies conducted during the severe acute respiratory syndrome (SARS) pandemic.

Long et al. used randomized trials to compare the effects of N95 respirators and surgical masks. They did not restrict their search by date, type or language of publication and did it in January 2020. They included 6 randomized trials (9171 participants).

Mukerji et al. used economic evaluations of mask or respirator use to evaluate their impact on respiratory infection transmission. They restricted their search to articles published in English and did their search in August 2014. They included 7 studies. None were from low-middle income settings.

What works:  Medical masks and N95 respirators reduce the risk of respiratory infection when worn by healthcare workers.

N95 respirators provide greater protection than medical masks against some types of respiratory infection when worn by healthcare workers, but universal use of N95 respirators throughout a work shift is likely to be less acceptable due to greater discomfort.

What doesn’t work: Disposable, cotton or paper masks are not recommended for protecting healthcare workers from respiratory infection.

What’s uncertain: In a 2015 review, there was insufficient economic evidence relating to the use of masks or respirators for reducing transmission of respiratory viruses. When considering the costs of these devices, costs should include those of the device itself and the associated fit testing and training.


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