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Now published in The Lancet

Physical Distancing, Face Masks, and Eye Protection to Prevent Person-Person COVID-19 Transmission: A Systematic Review and Meta-Analysis

46 Pages Posted: 26 May 2020

See all articles by Derek Chu

Derek Chu

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI); McMaster University - Michael G. DeGroote School of Medicine; The Research Institute of St. Joe’s Hamilton

Elie Akl

American University of Beirut - Department of Internal Medicine; American University of Beirut - Center for Systematic Reviews on Health Policy and Systems Research (SPARK); McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Amena El-Harakeh

American University of Beirut - Clinical Research Institute

Antonio Bognanni

Independent

Tamara Lotfi

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Mark Loeb

McMaster University - Department of Pathology and Molecular Medicine; McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Anisa Hajizadeh

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Anna Bak

AGH University of Science and Technology - Evidence Prime Software Lab

Ariel Izcovich

Hospital Alemán de Buenos Aires

Carlos A. Cuello-Garcia

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Chen Chen

Guangzhou University of Chinese Medicine - The Fourth Clinical Medical College

David James Harris

University of British Columbia (UBC) - Department of Medicine

Ewa Borowiack

AGH University of Science and Technology - Evidence Prime Software Lab

Fatimah Chamseddine

American University of Beirut - Clinical Research Institute

Finn Schünemann

Independent

Gian Paolo Morgano

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Giovanna Elsa Ute Muti Schünemann

Vita Salute San Raffaele University - Faculty of Medicine and Surgery

Guang Chen

Beijing University of Chinese Medicine - Dongzhimen Hospital

Hong Zhao

China Academy of Chinese Medical Sciences - Institute of Acupuncture and Moxibustion

Ignacio Neumann

Pontifical Catholic University of Chile - Department of Internal Medicine

Jeffrey Chan

Southlake Regional Health Centre - Department of Emergency Medicine

Joanne Khabsa

American University of Beirut - Clinical Research Institute

Layal Hneiny

American University of Beirut - Saab Medical Library

Leila Harrison

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Maureen Smith

Cochrane - Cochrane Consumer Executive

Nesrine Rizk

American University of Beirut - Department of Internal Medicine

Paolo Giorgi Rossi

Azienda Unità Sanitaria Locale (AUSL) - IRCCS di Reggio Emilia - Epidemiology Unit

Pierre AbiHanna

Rafik Hariri University - Rafik Hariri University Hospital

Rayane El-Khoury

American University of Beirut - Clinical Research Institute

Rosa Stalteri

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Tejan Baldeh

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Thomas Piggott

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Yuan Zhang

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Zahra Saad

American University of Beirut - Global Evidence Synthesis Initiative (GESI)

Assem Khamis

University of Hull - The Hull York Medical School

Marge Reinap

WHO Regional Office for Europe - WHO Country Office in Estonia; WHO Regional Office for Europe - WHO Division of Information, Evidence, Research and Innovation

Stephanie Duda

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Karla Solo

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI)

Sally Yaacoub

American University of Beirut - Clinical Research Institute

Holger Schünemann

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI); McMaster University - WHO Collaborating Center for Infectious Diseases, Research Methods and Recommendations; Cochrane - Michael G DeGroote Cochrane Canada Centre; McMaster University - GRADE Canada Centre

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Abstract

Background: Coronavirus disease 2019 (COVID-19) is spread person to person by virus through close contact. The optimal person-person distance and use of facemasks and/or eye protection to prevent disease transmission in healthcare and non-healthcare settings is debated.

Methods: We systematically reviewed the impact of distance, masks, and eye protection on transmission of COVID-19, SARS, or MERS from 21 standard, World Health Organization (WHO)-specific and COVID-19-specific data sources from inception to April 15, 2020 for studies of any design and language 1) comparing different distances between those infected and the people close to them, mask use, or eye protection, or 2) contextual factors of acceptability, feasibility, resource use, and equity of these interventions. We screened studies, extracted data, and assessed risk of bias in duplicate. Frequentist and Bayesian meta-analyses and meta-regression for the main outcome of viral transmission were by random effects. Secondary outcomes were contextual factors. We rated certainty of evidence rating per GRADE. PROSPERO: 177047.

Findings: We identified 0 RCTs and 164 relevant observational studies in healthcare and non-healthcare (community) settings from 16 countries across 6 continents. A physical distance of one metre or more compared to less than one metre from those infected was associated with 1) a lower risk of viral transmission (n=7782, 5.3% vs 15.5%; RD -10.2% [95%CI -11.5% to -7.5%], pooled adjusted odds ratio [aOR] 0.18 [95%CI 0.09-0.38], moderate certainty) and 2) incremental benefits with increasing distance, change in relative risk (RR) per metre 1.57 (moderate certainty). Facemask use was associated with less infection (n=2647, 2.7% vs 17.4%; RD -14.% [95% credible interval [CrI] -15.9% to -10.7%]; aOR 0.15 [95%CrI 0.07-0.34], low certainty), with stronger associations with N95 or similar (including powered) respirators compared to disposable surgical or similar (e.g. reusable 12-16-layer cotton) masks, p interaction =0.090; posterior probabilities for RR<1 of N95 vs surgical masks were >95% despite minimally informative priors; moderate certainty). Eye protection was associated with quantitatively similar lower risk of infection in 2 adjusted and 15 unadjusted studies (n=3751, 5.4% vs 16.0%; RD -10.6 [95%CI -12.5% to -7.7%]; RR 0.34 [95%CI 0.22-0.52]; aOR 0.22 [95%CI 0.12-0.39], low certainty).

Interpretation: This meta-analysis supports physical distancing by more than one metre and provides quantitative estimates for models and contact tracing to inform policy. Although direct evidence is limited, the optimal use of masks, in particular N95 or similar respirators, may depend on risk assessment and contextual factors. Eye protection may provide significant additional benefits. Globally collaborative, well-conducted studies on preventative and therapeutic strategies are required but are challenging to achieve immediately and, thus, recommendations in the interim to curtail the COVID-19 pandemic should be informed by this systematic appraisal of current evidence.

Funding Statement: Commissioned by the World Health Organization as a rapid review on March 25, 2020. The funders of the study helped with defining the scope of the question, but otherwise had no role in study design, data collection, data analysis, data interpretation, writing of the report, or the decision to submit it.

Declaration of Interests: ML is an investigator of an ongoing clinical trial on medical masks versus N95 respirators for COVID-19 (NCT04296643). All other authors declare no competing interests.

Ethics Approval Statement: The authors prospectively submitted the systematic review protocol for registration on PROSPERO (submission number 177047). This study followed PRISMA and MOOSE reporting guidelines.

Keywords: Covid-19; SARS; MERS; Planetary Health; Public Health; pandemic; Systematic Review and Meta-analysis; Physical distancing; Personal Protective Equipment; Facemasks; N95; Medical Mask; Cloth Mask; Eye protection; Goggles; GRADE; World Health Organization

Suggested Citation

Chu, Derek and Akl, Elie and El-Harakeh, Amena and Bognanni, Antonio and Lotfi, Tamara and Loeb, Mark and Hajizadeh, Anisa and Bak, Anna and Izcovich, Ariel and Cuello-Garcia, Carlos A. and Chen, Chen and Harris, David James and Borowiack, Ewa and Chamseddine, Fatimah and Schünemann, Finn and Morgano, Gian Paolo and Schünemann, Giovanna Elsa Ute Muti and Chen, Guang and Zhao, Hong and Neumann, Ignacio and Chan, Jeffrey and Khabsa, Joanne and Hneiny, Layal and Harrison, Leila and Smith, Maureen and Rizk, Nesrine and Rossi, Paolo Giorgi and AbiHanna, Pierre and El-Khoury, Rayane and Stalteri, Rosa and Baldeh, Tejan and Piggott, Thomas and Zhang, Yuan and Saad, Zahra and Khamis, Assem and Reinap, Marge and Duda, Stephanie and Solo, Karla and Yaacoub, Sally and Schünemann, Holger, Physical Distancing, Face Masks, and Eye Protection to Prevent Person-Person COVID-19 Transmission: A Systematic Review and Meta-Analysis (4/16/2020). Available at SSRN: https://ssrn.com/abstract=3578764 or http://dx.doi.org/10.2139/ssrn.3578764

Derek Chu

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

McMaster University - Michael G. DeGroote School of Medicine ( email )

1280 Main Street West
Hamilton, Ontario L8S 4L8
Canada

The Research Institute of St. Joe’s Hamilton ( email )

Hamilton
Canada

Elie Akl

American University of Beirut - Department of Internal Medicine ( email )

Beirut
Lebanon

American University of Beirut - Center for Systematic Reviews on Health Policy and Systems Research (SPARK) ( email )

Beirut
Lebanon

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Amena El-Harakeh

American University of Beirut - Clinical Research Institute ( email )

Lebanon

Antonio Bognanni

Independent ( email )

Tamara Lotfi

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Mark Loeb

McMaster University - Department of Pathology and Molecular Medicine ( email )

Hamilton, Ontario
Canada

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Anisa Hajizadeh

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Anna Bak

AGH University of Science and Technology - Evidence Prime Software Lab ( email )

Krakow
Poland

Ariel Izcovich

Hospital Alemán de Buenos Aires

Pueyrredón 1640
Buenos Aires, Buenos Aires 1118
Argentina

Carlos A. Cuello-Garcia

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Chen Chen

Guangzhou University of Chinese Medicine - The Fourth Clinical Medical College ( email )

China

David James Harris

University of British Columbia (UBC) - Department of Medicine ( email )

2775 Laurel Street, 10th Floor
Vancouver, British Columbia V5Z 1M9
Canada

Ewa Borowiack

AGH University of Science and Technology - Evidence Prime Software Lab ( email )

Krakow
Poland

Fatimah Chamseddine

American University of Beirut - Clinical Research Institute ( email )

Lebanon

Finn Schünemann

Independent ( email )

Gian Paolo Morgano

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Giovanna Elsa Ute Muti Schünemann

Vita Salute San Raffaele University - Faculty of Medicine and Surgery ( email )

Italy

Guang Chen

Beijing University of Chinese Medicine - Dongzhimen Hospital ( email )

Beijing, 100029
China

Hong Zhao

China Academy of Chinese Medical Sciences - Institute of Acupuncture and Moxibustion ( email )

China

Ignacio Neumann

Pontifical Catholic University of Chile - Department of Internal Medicine ( email )

Santiago
Chile

Jeffrey Chan

Southlake Regional Health Centre - Department of Emergency Medicine ( email )

Canada

Joanne Khabsa

American University of Beirut - Clinical Research Institute ( email )

Lebanon

Layal Hneiny

American University of Beirut - Saab Medical Library ( email )

Lebanon

Leila Harrison

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Maureen Smith

Cochrane - Cochrane Consumer Executive ( email )

United Kingdom

Nesrine Rizk

American University of Beirut - Department of Internal Medicine ( email )

Beirut
Lebanon

Paolo Giorgi Rossi

Azienda Unità Sanitaria Locale (AUSL) - IRCCS di Reggio Emilia - Epidemiology Unit ( email )

Italy

Pierre AbiHanna

Rafik Hariri University - Rafik Hariri University Hospital ( email )

Lebanon

Rayane El-Khoury

American University of Beirut - Clinical Research Institute ( email )

Lebanon

Rosa Stalteri

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Tejan Baldeh

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Thomas Piggott

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Yuan Zhang

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Zahra Saad

American University of Beirut - Global Evidence Synthesis Initiative (GESI) ( email )

Lebanon

Assem Khamis

University of Hull - The Hull York Medical School ( email )

United Kingdom

Marge Reinap

WHO Regional Office for Europe - WHO Country Office in Estonia ( email )

Estonia

WHO Regional Office for Europe - WHO Division of Information, Evidence, Research and Innovation ( email )

Denmark

Stephanie Duda

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Karla Solo

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

Sally Yaacoub

American University of Beirut - Clinical Research Institute ( email )

Lebanon

Holger Schünemann (Contact Author)

McMaster University - Department of Health Research Methods, Evidence, and Impact (HEI) ( email )

Hamilton, Ontario L8N 3Z5
Canada

McMaster University - WHO Collaborating Center for Infectious Diseases, Research Methods and Recommendations ( email )

Canada

Cochrane - Michael G DeGroote Cochrane Canada Centre ( email )

Canada

McMaster University - GRADE Canada Centre ( email )

Canada

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