The DOI matches its Crossref record; 8 of the 8 references it cites were found in a registry or an index.
Face masks for the public during the covid-19 crisis
Open accessAbstract
Trisha Greenhalgh and colleagues argue that it is time to apply the precautionary principle The precautionary principle is, according to Wikipedia, “a strategy for approaching issues of potential harm when extensive scientific knowledge on the matter is lacking.” The evidence base on the efficacy and acceptability of the different types of face mask in preventing respiratory infections during epidemics is sparse and contested.12 But covid-19 is a serious illness that currently has no known treatment or vaccine and is spreading in an immune naive population. Deaths are rising steeply, and health systems are under strain. This raises an ethical question: should policy makers apply the precautionary principle now and encourage people to wear face masks on the grounds that we have little to lose and potentially something to gain from this measure?3 We believe they should. Evidence based medicine tends to focus predominantly on internal validity—whether primary research studies were “done right”—using tools to assess risk of bias and adequacy of statistical analysis. External validity relates to a different question: whether findings of primary studies done in a different population with a different disease or risk state are relevant to the current policy question. We argue that there should be a greater focus on external validity in evaluation of masks. A rapid search of the literature on the wearing of masks by the general public during epidemics or pandemics by a team at the University of Galway (E Toomey, personal communication, 29 March 2020) found five peer reviewed systematic reviews:
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Cites
Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1
van Doremalen, N., Bushmaker, T., Morris, D. H., Holbrook, M. G., Gamble, A., Williamson, B. N., Tamin, A., Harcourt, J. L., Thornburg, N. J., Gerber, S. I., et al. (2020) · New England Journal of Medicine · doi:10.1056/nejmc2004973 · Cited by 9,951
The challenge of complexity in health care
Plsek, P. E., & Greenhalgh, T. (2001) · BMJ · doi:10.1136/bmj.323.7313.625 · Cited by 2,578
Self-citationFeasibility of controlling COVID-19 outbreaks by isolation of cases and contacts
Hellewell, J., Abbott, S., Gimma, A., Bosse, N. I., Jarvis, C. I., Russell, T. W., Munday, J. D., Kucharski, A. J., Edmunds, W. J., Sun, F., et al. (2020) · The Lancet Global Health · doi:10.1016/s2214-109x(20)30074-7 · Cited by 2,550
Quantifying SARS-CoV-2 transmission suggests epidemic control with digital contact tracing
Ferretti, L., Wymant, C., Kendall, M., Zhao, L., Nurtay, A., Abeler-Dörner, L., Parker, M., Bonsall, D., & Fraser, C. (2020) · Science · doi:10.1126/science.abb6936 · Cited by 2,512
Respiratory virus shedding in exhaled breath and efficacy of face masks
Leung, N. H. L., Chu, D. K. W., Shiu, E. Y. C., Chan, K.-H., McDevitt, J. J., Hau, B. J. P., Yen, H.-L., Li, Y., Ip, D. K. M., Peiris, J. S. M., et al. (2020) · Nature Medicine · doi:10.1038/s41591-020-0843-2 · Cited by 2,270
Physical interventions to interrupt or reduce the spread of respiratory viruses
Jefferson, T., Del Mar, C. B., Dooley, L., Ferroni, E., Al-Ansary, L. A., Bawazeer, G. A., van Driel, M. L., Nair, N. S., Jones, M. A., Thorning, S., et al. (2011) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd006207.pub4 · Cited by 805
Face mask use and control of respiratory virus transmission in households
MacIntyre, C. R., Cauchemez, S., Dwyer, D. E., Seale, H., Cheung, P., Browne, G., Fasher, M., Wood, J., Gao, Z., Booy, R., et al. (2009) · Emerging Infectious Diseases · doi:10.3201/eid1502.081166 · Cited by 461
Xiao, J., Shiu, E. Y. C., Gao, H., Wong, J. Y., Fong, M. W., Ryu, S., & Cowling, B. J. (2020) · Emerging Infectious Diseases · doi:10.3201/eid2605.190994 · Cited by 243
Research works printed but not linked: 17
- 10.1016/S2213-2600(20)30134-X · DOI · Paper page
- 10.21203/rs.3.rs-16701/v2. · doi:10.21203/rs.3.rs-16701/v2
- 10.1111/jebm.12381 · DOI · Paper page
- 10.1017/S0950268809991658 · DOI · Paper page
- 10.1186/1471-2458-7-208 · DOI · Paper page
- 10.1101/2020.04.01.20049528 · doi:10.1101/2020.04.01.20049528
- 10.1136/bmjopen-2014-006577 · DOI · Paper page
- 10.1056/NEJMe2002387 · DOI · Paper page
- 10.1101/2020.03.05.20031815 · doi:10.1101/2020.03.05.20031815
- 10.1001/jama.2020.4958 · doi:10.1001/jama.2020.4958
- 10.1101/2020.03.12.20034660 · DOI
- 10.1038/s41591-020-0843-2 · DOI · Paper page
- 10.3201/eid1004.030628 · DOI · Paper page
- Nyei A-bI, 2016, Beyond the disease: how the Ebola epidemic affected the politics and stability of the Mano River Basin, Conflict Trends, 2, 12
- 10.1136/bmj.333.7570.701 · DOI
- Smith, 2006, Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials, Int J Prosthodont, 19, 126
- 10.1101/2020.03.30.20047217 · DOI
Cited by
Chu, D. K., Akl, E. A., Duda, S., Solo, K., Yaacoub, S., Schünemann, H. J., Chu, D. K., Akl, E. A., El-harakeh, A., Bognanni, A., et al. (2020) · The Lancet · doi:10.1016/s0140-6736(20)31142-9 · Cited by 3,843
COVID-19 and Public Transportation: Current Assessment, Prospects, and Research Needs
Tirachini, A., & Cats, O. (2020) · Journal of Public Transportation · doi:10.5038/2375-0901.22.1.1 · Cited by 781
Lyu, W., & Wehby, G. L. (2020) · Health Affairs · doi:10.1377/hlthaff.2020.00818 · Cited by 721
Pfattheicher, S., Nockur, L., Böhm, R., Sassenrath, C., & Petersen, M. B. (2020) · Psychological Science · doi:10.1177/0956797620964422 · Cited by 574
Who is wearing a mask? Gender-, age-, and location-related differences during the COVID-19 pandemic
Haischer, M. H., Beilfuss, R., Hart, M. R., Opielinski, L., Wrucke, D., Zirgaitis, G., Uhrich, T. D., & Hunter, S. K. (2020) · PLOS ONE · doi:10.1371/journal.pone.0240785 · Cited by 513
Metadata
- Authors
- Greenhalgh, T., Schmid, M. B., Czypionka, T., Bassler, D., & Gruer, L.
- Venue
- BMJ
- Publisher
- BMJ
- Published
- 2020-04-09
- Volume
- 369
- Pages
- m1435
- ISSN
- 1756-1833 (ISSN-L)
- OpenAlex
- W3015840999
- Cited by
- 623
- References
- 8
- FWCI
- 71.05
- Type
- journal article
- Language
- en
- Open access
- bronze
- Licence
- www.bmj.com/company/legal-information/terms-conditions/legal-information/tdm-licencepolicy (tdm)
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Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).
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