02 Jun Study Confirms Social Distancing, Face Masks and Eye Protection Can Reduce COVID-19 Transmission
MedicalResearch.com Interview with:
Holger Schünemann, MD, PhD, FRCPC
Professor of Clinical Epidemiology and of Medicine
Co-Director, WHO Collaborating Centre for Infectious Diseases,
Research Methods and Recommendations
Director, Cochrane Canada and McMaster GRADE Centre
Department of Health Research Methods, Evidence, and Impact
MedicalResearch.com: What is the background for this study?
Response: Many countries and regions have issued conflicting advice about physical distancing to reduce transmission of COVID-19, based on limited information. In addition, the questions of whether masks and eye coverings might reduce transmission of COVID-19 in the general population, and what the optimum use of masks in healthcare settings is, have been debated during the pandemic.
MedicalResearch.com: What are the main findings?
Response: For the current analysis, we formed an international and multidisciplinary team of researchers, and did a systematic review of 172 observational studies assessing distance measures, face masks, and eye protection to prevent transmission between patients with confirmed or probable COVID-19, SARS, or MERS infection and individuals close to them (eg, caregivers, family, healthcare workers), up to May 3, 2020. The COVID-19 studies included in the analysis consistently reported a benefit for the three interventions and had similar findings to studies of SARS and MERS.
Pooled estimates from 44 comparative studies involving 25,697 participants were included in the meta-analysis.
- First review of all available evidence including 172 observational studies looking at how physical distancing, face masks, and eye protection affect the spread of COVID-19, SARS, and MERS in both community and healthcare settings across 16 countries.
- Physical distancing of at least 1 metre lowers risk of COVID-19 transmission, but distances of 2 metres could be more effective.
- Face coverings and masks might protect both healthcare workers and the general public against infection with COVID-19, and protective eye covering may also provide additional benefit—although the certainty of the evidence is low for both forms of protection.
- Importantly, even when properly used and combined, none of these interventions offers complete protection and other basic protective measures (such as hand hygiene) are essential to reduce transmission.
MedicalResearch.com: What should readers take away from your report?
Response: Our findings are the first to synthesise all direct information on COVID-19, SARS, and MERS, and provide the currently best available evidence on the optimum use of these common and simple interventions to help “flatten the curve” and inform pandemic response efforts in the community. Governments and the public health community can use our results to give clear advice for community settings and healthcare workers on these protective measures to reduce infection risk.
Keeping at least one metre from other people as well as wearing face coverings and eye protection, in and outside of health-care settings, could be the best way to reduce the chance of viral infection or transmission of COVID-19, according to our systematic review and meta-analysis synthesising all the available evidence from the scientific literature, published in The Lancet.
For healthcare workers, N95 and other respirator-type masks might be associated with a greater protection from viral transmission than surgical masks or similar (eg, reusable 12-16 layer cotton or gauze masks). For the general public, face masks are also probably associated with protection, even in non-health-care settings, with either disposable surgical masks or reusable 12-16 layer cotton ones. However, the authors note that there are concerns that mass face mask use risks diverting supplies from health-care workers and other caregivers at highest risk for infection.
Policy makers will need to assess access issues for face masks to ensure that they are equally available for all. With respirators such as N95s, surgical masks, and eye protection in short supply, and desperately needed by healthcare workers on the front lines of treating COVID-19 patients, increasing and repurposing of manufacturing capacity is urgently needed to overcome global shortages. Solutions might have to be found for making face masks available to the general public. However, people must be clear that wearing a mask is not an alternative to physical distancing, eye protection or basic measures such as hand hygiene, but might add an extra layer of protection.
Indeed, none of the 3 studied interventions, even when properly used and combined, give complete protection from infection, and note that some of the findings, particularly around face masks and eye protection, are supported by low-certainty evidence, with no completed randomised trials addressing COVID-19 for these interventions (table 2).
We also stress the importance of using information about how acceptable, feasible, resource intense, and equally accessible to all the use of these interventions are when devising recommendations. Across 24 studies of all three viruses including 50,566 individuals, most participants found these personal protection strategies acceptable, feasible, and reassuring, but noted harms and challenges including frequent discomfort and facial skin breakdown, increased difficulty communicating clearly, and perceived reduced empathy from care providers by those they were caring for.
MedicalResearch.com: What recommendations do you have for future research as a result of this work?
Response: Globally collaborative, well-conducted studies of different personal protective strategies are required, but recommendations in the interim aiming to curtail the current COVID-19 pandemic and future waves could be made on the basis of this systematic appraisal of current evidence.
MedicalResearch.com: Is there anything else you would like to add?
Response: The study was in part funded by the World Health Organization. It was conducted by researchers at McMaster University, Canada; the American University of Beirut, Lebanon; German Hospital of Buenos Aires, Argentina; Southlake Regional Health Centre, Canada; University of British Columbia, Canada; McMaster University, Canada; The Research Institute of St. Joe’s Hamilton, Canada; Pontificia Universidad Católica de Chile, Chile; Beijing University of Chinese Medicine, China; Dongzhimen Hospital, China; Guangzhou University of Chinese Medicine, The Fourth Clinical Medical College, China; China academy of Chinese Medical Science, China; American University of Beirut, Lebanon; Rafik Hariri University Hospital, Lebanon; The London School of Hygiene & Tropical Medicine, UK; University of Hull, UK.
Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis
Chu, Derek KChu, Derek K et al.
The Lancet, Volume 0, Issue 0
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