POLICY BRIEF | APRIL, 2020 Can masks help with reopening the economy? By Maria Polyakova, Jason Andrews, Stephen Luby and Jeremy Goldhaber-Fiebert KEY TAKEAWAYS Even as people follow the rules of social distancing during the coronavirus pandemic, many still ask how they can best n The United States, China, Austria, Germany and keep themselves safe when it comes to grocery shopping or some other countries are being in situations where others are clustered. Should I wear now starting to consider gloves? And what about masks? Once businesses reopen and recommending or are already requiring that people wear people head back to stores and restaurants, will wearing a medical masks in public. But mask still offer a smart level of protection? the WHO still recommends The United States, Austria, Germany and some other countries outside of against wearing them as long Asia — where mask use is already much more common — are now starting as you’re feeling well. to consider recommending or are already requiring that people wear simple medical or even home-made cloth masks in public. n Evidence from existing observational studies and But the World Health Organization still recommends against wearing masks as randomized trials supports the long as you’re feeling well. The big reasons, they’ve argued, is that masks are effectiveness of medical masks ineffective and may increase risk to those who wear them incorrectly.1 in reducing transmission of That recommendation deserves reconsideration, especially as policymakers respiratory infections in a think about what steps can be taken to ensure public safety while allowing variety of settings. more economic activity to resume. n Revising recommendations for expanding the use of masks in public areas is justified and may eventually help the economy with transitioning into the post-COVID world. 1 World Health Organization, “Coronavirus disease (COVID-19) advice for the public: When and how to use masks” https://www.who.int/emergencies/diseases/novel-coronavirus-2019/ advice-for-public/when-and-how-to-use-masks John A. and Cynthia Fry Gunn Building siepr.stanford.edu 366 Galvez Street, Stanford, CA 94305-6015 @siepr facebook.com/SIEPR/ 1 POLICY BRIEF | APRIL, 2020 What the evidence shows What policymakers can do Empirical evidence from existing observational studies As recently pointed out by some scientists following and randomized trials supports the effectiveness of COVID-19, WHO’s recommendation against the use of medical masks in reducing transmission of respiratory masks by healthy people in community settings is based infections in a variety of settings. on the interpretation of this existing body of research as providing no evidence for the effectiveness of mask use Most observational studies, particularly around the SARS in the community (Leung et al 2020; Feng et al 2020). The outbreak, have found mask wearing protects against Centers for Disease Control and Prevention had followed infection. The evidence from randomized trials has been a similar interpretation in the U.S., though both it and more mixed. the WHO recommend the use of masks for symptomatic Several trials, conducted in community and health care patients and health care professionals as effective means settings, showed that wearing masks — when combined of preventing transmission. with thorough handwashing — proved to protect against While the quality of evidence supporting the respiratory infections, while other trials found no effectiveness of masks in health care settings is certainly benefits. In many of these studies, less than 50 percent better, the firm recommendation against masks in of participants actually used the protective measures, so community settings appears incompatible with the that if more people take up these measures in the face of available evidence. the pandemic, the benefit may be larger than what was found in the trials. The strength of the recommendations against wearing masks appear to stem from two additional concerns: that The most comprehensive reviews of the literature on the the public would wear masks incorrectly, undermining their effectiveness of masks for interruption or reduction of effectiveness; and that wide-spread community use would the respiratory virus spread were conducted by Jefferson exacerbate mask shortages for health care professionals. et al. in a 2011 Cochrane report and MacIntyre and Chughtai’s 2015 overview of the evidence. The World Health Organization has indicated that wearing masks incorrectly can increase one’s risk of Both reviews concluded that existing research supports infection. But there is not sufficient evidence to support the notion that having people wear masks makes the notion that people could not wear masks effectively. good sense. Even if it can’t be measured with absolute Many masks are packaged with detailed instructions certainty how much masks alone are responsible for for how to use them. And online videos could easily be cutting infection rates, there is no evidence to suggest posted to teach people how to wear a mask correctly. that wearing a mask is dangerous for one’s health. Both The theoretical risk of increasing acquisition of infection, reviews acknowledge that the design, sample size, and while frequently cited by authorities, does not seem to analyses of the underlying studies are frequently non- be supported by a finding of increased risk in any of the ideal, limiting definitive conclusions on effectiveness. available studies. Nevertheless, the balance of evidence suggests a benefit of mask use in community settings, including among Appeals to the public not to stockpile masks so as to those who aren’t feeling sick, especially when masks are keep them available for health care professionals have deployed early with respect to exposures and used in generally not been effective, with widely reported stock- conjunction with other measures. outs and shortages despite such appeals. We speculate that such appeals failed because the general public did not find the argument that masks are ineffective in community settings to be credible. John A. and Cynthia Fry Gunn Building siepr.stanford.edu 366 Galvez Street, Stanford, CA 94305-6015 @siepr facebook.com/SIEPR/ 2 POLICY BRIEF | APRIL, 2020 Moreover, it is possible that initial (and ongoing at the activity, while prolonged uncertainty may be harmful for time of this writing) WHO and CDC guidelines against the firms (Bloom 2009). use of masks in the community by individuals without Having a mask and knowing how to use it may serve as symptoms may have unintentionally decreased the an extra crutch to help with inevitable consumer anxiety. required sense of urgency and commitment of private and public resources for addressing underlying mask shortages for the general population. The result is that References acute shortages of masks undercut even existing CDC recommendations; many individuals who are ill or N. Bloom, “The Impact of Uncertainty Shocks,” Econometrica, vol. 77, no. 3, p. 623–685, 2009 visiting a health care facility with suspected COVID-19 symptoms cannot obtain masks. S. Feng, C. Shen, N. Xia, W. Song, M. Fan, B. Cowling “Rational use of face masks in the COVID-19 pandemic,” The Lancet Respiratory Medicine, 20 Revising recommendations for expanding the use of March 2020 masks in public areas is justified by the evidence. And S. Flaxman, S. Mishra, A. Gandy and e. al., “Estimating the number of guidelines to wear masks as part of other public efforts — infections and the impact of non-pharmaceutical interventions on including social distancing — to control the spread of COVID-19 in 11 European countries,” Imperial College London, 2020. COVID-19 could help steer the production energy and T. Jefferson, C. Del Mar, L. Dooley, E. Ferroni, L. Al-Ansary, G. Bawazeer, M. resources of both private and public players to ensuring van Driel, S. Nair, M. Jones, S. Thorning and C. JM, “Physical interventions there are enough masks for everyone. to interrupt or reduce the spread of respiratory viruses,” Cochrane Database of Systematic Reviews, 2011. C. C. Leung, T. H. Lam and K. K. Cheng, “Mass masking in the COVID-19 Supporting the economy epidemic: people need guidance,” The Lancet, 03 March 2020. We further speculate that deployment of masks in C. R. MacIntyre and A. A. Chughtai, “Facemasks for the prevention of public areas may eventually help the economy with infection in healthcare and community settings,” BMJ, p. 350:h694, 2015. transitioning into the post-COVID world. First, masks could prove to be a cost-effective way of trying to reduce re-emergence of the virus in the medium run, as epidemiologic models suggest that virus re- emergence may necessitate re-introduction of social distancing measures with some regularity over the course of next 12 to 18 months (Flaxman et al. 2020). But wearing masks could give some hope of removing the need to put the economy into the switch on, switch off mode — which would require many businesses to close, open, and close again on short notice Second, once official restrictions on many forms of economic activity are lifted, it is very likely that consumers will be hesitant in returning to their pre- pandemic levels of consumption of goods and services outside of their homes. Consumers’ behavioral sentiments are crucial for charting course of economic John A. and Cynthia Fry Gunn Building siepr.stanford.edu 366 Galvez Street, Stanford, CA 94305-6015 @siepr facebook.com/SIEPR/ 3 POLICY BRIEF | APRIL, 2020 Maria Polyakova is a faculty fellow The Stanford Institute for Economic Policy at SIEPR and an assistant professor Research (SIEPR) catalyzes and promotes evidence- of medicine at Stanford. She is a based knowledge about pressing economic core faculty member at Stanford issues, leading to better-informed policy solutions Health Policy. Her research for generations to come. We are a nonpartisan interests include health economics, public research institute, and SIEPR Policy Briefs reflect economics and industrial organization. the views and ideas of the author only. Jason Andrews is an assistant professor of medicine (infectious diseases) at Stanford. He is also a practicing infectious disease physician and a faculty affiliate at the Stanford King Center on Global Development. Stephen Luby is a professor of medicine (infectious diseases) at Stanford and a faculty affiliate of the Stanford King Center on Global Development. He is a core faculty member at Stanford Health Policy and a senior fellow at the Stanford Woods Institute for the Environment and the Freeman Spogli Institute for International Studies. Jeremy Goldhaber-Fiebert is an associate professor of medicine at Stanford and a core faculty member at Stanford Health Policy. John A. and Cynthia Fry Gunn Building siepr.stanford.edu 366 Galvez Street, Stanford, CA 94305-6015 @siepr facebook.com/SIEPR/ 4