Intended for healthcare professionals

Letters Face masks for the public during covid-19

Laying straw men to rest: author’s reply to “Urgency and uncertainty: covid-19, face masks, and evidence informed policy”

BMJ 2020; 369 doi: (Published 08 June 2020) Cite this as: BMJ 2020;369:m2240
  1. Trisha Greenhalgh, professor of primary care health sciences
  1. Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford OX2 6GG, UK
  1. trish.greenhalgh{at}

In the eight weeks since it was published, our article in The BMJ on the public wearing face masks during the covid-19 pandemic has been cited 60 times and has an Altmetric score of over 3000.1 Our basic argument for applying the precautionary principle seems to have drawn much sympathy from scientists and clinicians.

In those eight weeks many additional empirical studies have been published that support the efficacy or confirm the lack of serious harms associated with the lay public wearing face masks. To my knowledge, no robust study has been published that bears out the claim that the harms of wearing face masks in this pandemic outweigh the benefits.

In sum, I think that the arguments put forward in Martin and colleagues’ letter are essentially straw men propped up by selective citation.2 I have addressed them in detail in an open access, peer reviewed paper, with 89 references, recently published in the Journal of Evaluation in Clinical Practice.3 Martin and colleagues were well aware of that article—a preprint was published some weeks ago, and they corresponded with me about it on social media.


  • Competing interests: I am the author of the article being criticised. I have no personal interest in the use of face masks or coverings, though I do have a scientific one.

This article is made freely available for use in accordance with BMJ's website terms and conditions for the duration of the covid-19 pandemic or until otherwise determined by BMJ. You may use, download and print the article for any lawful, non-commercial purpose (including text and data mining) provided that all copyright notices and trade marks are retained.


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