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

Abstract

Study design: Systematic review and meta-analysis of 21 standard World Health Organization-specific and COVID-19-specific sources through May 3, 2020.Key findings: In a review of 25,697 patients, transmission of viruses was lower with physical distancing of 1 meter or more compared with less than 1 meter. Protection was increased as distance was lengthened (absolute risk, 3% with longer distance vs 13% with shorter distance). Face mask use could result in a large reduction in risk of interaction (adjusted risk, 3% with face masks vs 17% without). There was a stronger association with protection using N95 masks compared with disposable surgical masks or reusable cotton masks. Eye protection also was associated with less infection.Conclusion: These findings support physical distancing of 1 meter or more. Optimum use of face masks and eye protection in public and health care settings should be informed by these findings.Commentary: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19 and is spread person to person through close contact. With no effective pharmacologic interventions or vaccine expected in the near future, reducing the rate of infection (flattening the curve) is a priority. Added benefits are likely with even larger physical distances, such as 2 meters (6 feet, which we keep hearing about) or more. The use of face masks, including N95 and surgical or similar masks (12-to 16-layer cotton or gauze masks), and eye protection is clearly beneficial. For the general public, this report confirms previous recommendations that physical distancing of more than 1 meter is highly effective and that face masks are associated with protection. Other basic measures, such as hand hygiene, are still needed.I am growing more disheartened by my fellow man (and woman) as things open up during the pandemic. This past weekend, I went to a barbecue outside of Philadelphia, which was attended by many physicians, and to my older brother's outdoor 70th birthday party in northern New Jersey, which was especially hard-hit by the virus. At both events, none of the guests wore masks but would sidle up to my wife, my son, and me as if everything were normal. I can think of four reasons that people would not follow recommendations such as maintaining at least 3-to 6-foot distancing and wearing face masks: (1) they know they don't have the virus (even without being tested); (2) they know they won't get sick because they're young, or they're older but otherwise healthy; (3) they don't believe the science (I don't have patience for these people); or (4) they believe we are all going to get the virus anyway, so get it over with and let's move on (I know very intelligent people who support this last reason). I don't want to tread political waters, but I wish these individuals would acknowledge there may be others who don't agree with this laissez-faire reasoning. Some people may want to maintain social distancing at an outdoor eventdand maybe even wear a face mask.

Reduced Treatment Sensitivity of SARS-CoV-2 After Multigenerational Human-to-Human Transmission

“…Population movement between regions is an important factor influencing the spread of epidemics [15], while virus testing along with case isolation and community quarantine has been proved to be able to prevent rapid local outbreak [16]. Physical distancing of 1 m or more and wearing masks are also believed to significantly reduce the risk of virus transmission [17]. In addition, the government's promotion of positive preventive measures can contribute to the inhibition of the outbreak [18].…”

Aerosol Transmission of SARS-CoV-2: Physical Principles and Implications

“…There is epidemiological evidence that masks reduce infection, even when imperfect (118,119). Any face covering will catch large droplets from a cough or sneeze (120), but aerosol particles follow the airflow and escape through any gaps at the edges (19).…”

Public Health and Risk Communication During COVID-19—Enhancing Psychological Needs to Promote Sustainable Behavior Change

“…The main reasons for these discrepancies were the limited evidence on their efficacy in preventing respiratory infections during epidemics; the need to preserve limited supplies of face masks for professional use in healthcare settings; the argument that face masks may create a false sense of security and lead to neglecting other important measures such as hand hygiene and social distancing, and that people may not wear them properly or repeatedly touch their mask, causing more harm than good (26,27). Recent research has shown that face masks could reduce the transmission of the virus (28,29), resulting in many governments advising or mandating the use of masks for healthy individuals in the community. However, there are still debates on the potential risks of wearing masks, such as unintended negative consequences and the effectiveness of different face coverings (30,31).…”