As the spread of coronavirus disease 2019 (COVID-19) outside China is accelerating, we urge policy makers to reconsider the role of masking.

1 Guan WJ

Ni ZY

Hu Y

et al. Clinical characteristics of the 2019 novel coronavirus infection in China. The non-specific symptoms at early stages of COVID-19 and absence of clear transmission links have defied conventional containment strategy by case isolation and contact quarantine.So far, only compulsory social distancing, coupled with mass masking, appears to be successful, at least temporarily, in China. However, whether such an approach is sustainable in the Chinese economy or enforceable in other social systems is doubtful.

2 WHO

Advice on the use of masks in the community, during home care and in health care settings in the context of the novel coronavirus (2019-nCoV) outbreak: interim guidance. 3 Teasdale E

Santer M

Geraghty AW

Little P

Yardley L Public perceptions of non-pharmaceutical interventions for reducing transmission of respiratory infection: systematic review and synthesis of qualitative studies. 4 Bai Y

Yao L

Wei T

et al. Presumed asymptomatic carrier transmission of COVID-19. , 5 Zou L

Ruan F

Huang M

et al. SARS-CoV-2 viral load in upper respiratory specimens of infected patients. WHO recommends against wearing masks in community settings because of lack of evidence.However, absence of evidence of effectiveness should not be equated to evidence of ineffectiveness, especially when facing a novel situation with limited alternative options. It has long been recommended that for respiratory infections like influenza, affected patients should wear masks to limit droplet spread. If everyone puts on a mask in public places, it would help to remove stigmatisation that has hitherto discouraged masking of symptomatic patients in many places.Furthermore, transmission from asymptomatic infected individuals has been documented for COVID-19, and viral load is particularly high at early disease stage.Masking, as a public health intervention, would probably intercept the transmission link and prevent these apparently healthy infectious sources.

Global shortage of disposable surgical masks is a real and expanding problem. So-called mass mask panic has occured irrespective of advice from public health authorities. Panic buying of masks in Hong Kong has gone unresolved for more than 30 days, and a similar situation seems to be developing in Italy. People wear masks to protect themselves in close person-to-person contacts, but unintentionally, they are protecting each other through source control. Disposable surgical masks and their technical specifications were designed specifically for the protection of health-care workers during occupational exposures. Cloth masks were used by surgeons successfully during operations before disposable masks were available. In real life, most people in all seriously affected areas are reusing their disposable masks. All governments must prepare to handle the probable mass panic and explore other sustainable alternatives to the disposable masks for effective source control in community settings.

With the imminent pandemic, health authorities need to decide rapidly whether they should adopt mass masking in their own localities and make advance preparations to avoid confusion and chaos in the anticipated challenges ahead.

We declare no competing interests.

Article Info Publication History Identification DOI: https://doi.org/10.1016/S0140-6736(20)30520-1 Copyright © 2020 Elsevier Ltd. All rights reserved. ScienceDirect Access this article on ScienceDirect