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Focus on Covid-19

COVID-19 Summaries: a recap of recent research

Anne Chang, Richard T. Ellison III, Rajesh T. Gandhi, Andrew Henderson, Christine McDonald, Renae McNamara, Natasha Smallwood
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Abstract

Knowledge is evolving rapidly on the properties of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and the clinical syndrome coronavirus disease 2019 (COVID-19), and guidance on management will change over time. Respiratory Medicine Today brings you a selection of summaries and commentary on some of the recent research findings on SARS-CoV-2 and COVID-19 published in the international literature.

Preventing COVID-19: physical distancing, face masks and eye protection

Findings of this meta-analysis support physical distancing and the use of face masks and eye protection to help prevent virus transmission.1

Physical distancing of at least 1 metre may reduce the risk of SARS-CoV-2 transmission but distances of 2 metres could be more effective, according to a systematic review and meta-analysis.

Published in The Lancet, the review of 172 observational studies across 16 countries also found that protective eye coverings and face masks were protective for healthcare workers and the general public.

The researchers identified 44 comparative studies of 25,697 patients with COVID-19, severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS) in healthcare and nonhealthcare settings. They found that physical distancing of 1 metre or more was associated with an 82% lower risk of infection (adjusted odds ratio [aOR], 0.18) compared with a distance of less than 1 metre. Risk was lowered further with increasing distance, extrapolated up to 3 metres.

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Use of face masks and respirators reduced the risk of infection by 85% (aOR, 0.15) compared with no face mask use. N95 respirators were linked with greater protection than disposable surgical face masks or similar (e.g. reusable 12- to 16-layer cotton masks), but both were protective. After adjusting for N95 respirator use in the healthcare setting, the researchers found face-mask use to be similarly effective in both the healthcare and nonhealthcare settings.

Eye protection with face shields, goggles and glasses was also found to be protective, with a 78% lower risk of infection compared with no eye protection (aOR, 0.22).

None of these interventions, even when properly used and combined, provided complete protection from infection, the researchers noted, stressing the need for other basic measures such as hand hygiene.

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Comment by Professor Christine McDonald AM

Chu and colleagues’ meta-analysis, supported by the WHO, included studies of observational data from both healthcare and nonhealthcare settings, including 44 comparative studies involving nearly 26,000 patients with COVID-19, SARS or MERS.1 Their findings confirmed the importance of measures such as physical distancing, protective eye covering and facemasks in both settings. They observed that in healthcare settings N95 or similar respirators were 96% effective (aOR, 0.04; 95% CI, 0.004–0.30) compared with other masks, which were 67% effective (aOR, 0.33; 95% CI, 0.17–0.61) and noted the importance of eye protection which resulted in a 78% reduction in infection.

Discussion in this paper included the biological plausibility of aerosol spread of SARS-CoV-2, albeit with a lack of data to support viable virus in the air outside of aerosol generating procedures. The authors were unable to identify robust data to inform other aspects relevant to spread of infection, such as ventilation and healthcare setting (ED/ICU/ward-based /other), that may modify the degree of protection provided by personal protection strategies. Of note, the accompanying editorial by MacIntyre, et al. strongly supported the use of a respirator as the minimum standard of care for healthcare workers on COVID-19 wards, based on the precautionary principle.2 

Of relevance to this discussion, in the Australian setting, Victorian Chief Medical Officer Andrew Wilson reported on 25 August 2020 that 70 to 80% of healthcare workers infected with SARS-CoV-2 in Victoria’s second wave of infection were infected at work.3

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1. Chu DK, et al, on behalf of the COVID-19 Systematic Urgent Review Group Effort (SURGE) study authors. 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. Lancet 2020; 395: 1973-1987; https://doi.org/10.1016/S0140-6736(20)31142-9
2. McIntyre CR, et al. Physical distancing, face masks, and eye protection for prevention of  COVID-19. Lancet 2020; 395: 1950-1951.
3. Remeikis A. Coalition criticises Victorian government’s handling of pandemic – as it happened. The Guardian 2020; 25 August.  https://theguardian.com/australia-news/live/2020/aug/25/coronavirus-australia-latest-updates-scott-morrison-jobkeeper-economy-business-health-nsw-covid-19-testing-victoria-inquiry-live-news.

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Professor Anne Chang am,* Respiratory Specialist, Head, Child Health Division, Menzies School of Health Research, Darwin, NT. Professor Richard T. Ellison III, MD, Professor of Medicine, Microbiology, and Physiological Systems, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, USA. Professor Rajesh T. Gandhi, MD, Professor of Medicine, Harvard Medical School; Director, HIV Clinical Services and Education, Massachusetts General Hospital, Boston, USA. Dr Andrew Henderson,* Infectious Diseases Specialist, Princess Alexandra Hospital, Brisbane, Qld. Professor Christine McDonald am,* Director, Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Vic; Department of Medicine, University of Melbourne, Melbourne, Vic. Dr Renae McNamara,* Clinical Specialist Physiotherapist, Pulmonary Rehabilitation Coordinator, Prince of Wales Hospital, Sydney, NSW. Associate Professor Natasha Smallwood, Clinical Associate Professor and Honorary Principal Fellow, Department of Medicine, University of Melbourne, and Respiratory Physician, Department of Respiratory and Sleep Medicine, The Royal Melbourne Hospital, Melbourne, Vic. Acknowledgements We thank Dr Sebastian Le Feuvre, Thoracic and Sleep Physician, and Professor Ian Yang, Thoracic Physician, The Prince Charles Hospital and The University of Queensland, Brisbane, Qld, for reviewing the selection of research papers summarised in this article. We are also grateful for the assistance of members of Lung Foundation Australia’s COVID-19 Expert Working Group,* in compiling this article.