Editorials
Surgical face masks to prevent respiratory symptoms
BMJ 2024; 386 doi: https://doi.org/10.1136/bmj.q1843 (Published 23 August 2024) Cite this as: BMJ 2024;386:q1843Linked Research
Personal protective effect of wearing surgical face masks in public spaces on self-reported respiratory symptoms in adults
Mask research must take account of mechanism
This editorial, and the linked RCT [1], pay scant attention to HOW masks might work. Fundamental to the science of masking is the mechanism of transmission of respiratory pathogens, which is predominantly airborne [2]. This means that surgical masks, which are designed primarily to stop splashes and generally fit loosely round the face, are at best weak protection against respiratory infections. The required design is a well-fitting respirator. We wrote about this topic in depth in a recent comprehensive state of the science review [3].
Trials of sub-optimally designed interventions are potentially wasteful and misleading. Those who believe that we still need RCTs of facial protection should be testing respirators, not surgical masks.
1. Solberg R B, Fretheim A, Elgersma I H, Fagernes M, Iversen B G, Hemkens L G et al. Personal protective effect of wearing surgical face masks in public spaces on self-reported respiratory symptoms in adults: pragmatic randomised superiority trial BMJ 2024; 386 :e078918 doi:10.1136/bmj-2023-078918.
2. Wang CC, Prather KA, Sznitman J, Jimenez JL, Lakdawala SS, Tufekci Z, Marr LC. 2021. Airborne transmission of respiratory viruses. Science 373:eabd9149.
3. Greenhalgh T, MacIntyre CR, Baker MG, Bhattacharjee S, Chughtai AA, Fisman D, Kunasekaran M, Kvalsvig A, Lupton D, Oliver M, Tawfiq E, Ungrin M, Vipond J. 2024. Masks and respirators for prevention of respiratory infections: a state of the science review. Clin Microbiol Rev 37:e00124-23.
https://doi.org/10.1128/cmr.00124-23
Competing interests: Member of Independent SAGE