Literature Review Supports Physician Distancing, Masks As COVID-19 Protection

Is all of the physical distancing and stocking up on protective equipment at pharmacies and elsewhere really helping to control COVID-19 infections? A new review commissioned by the World Health Organizations says those measures really do appear to be effective. Here is more information.

HAMILTON, ONTARIO – As pharmacies are rearranged and staff don protective equipment to provide better protection against COVID-19, questions remain about optimal practices.

A report in The Lancet offers a comprehensive review of existing evidence, supporting physical distancing of two meters (about 6.5 feet) or more to prevent person-to-person transmission of COVID-19.

The international team led by McMaster University and St. Joseph's Healthcare Hamilton in Canada also emphasize that face masks and eye protection decrease the risk of infection.

The systematic review and meta-analysis were commissioned by the World Health Organization.

"Physical distancing likely results in a large reduction of COVID-19," explained Holger Schünemann, MD, PhD, professor of the departments of health research methods, evidence, and impact, and medicine at McMaster, who led the effort. Schünemann is co-director of the World Health Organization (WHO) Collaborating Centre for Infectious Diseases, Research Methods and Recommendations.

"Although the direct evidence is limited, the use of masks in the community provides protection, and possibly N95 or similar respirators worn by health-care workers suggest greater protection than other face masks," he noted. "Availability and feasibility and other contextual factors will probably influence recommendations that organizations develop about their use. Eye protection may provide additional benefits."

Among the participants in the review were front-line and specialist clinicians, epidemiologists, patients, public health and health policy experts of published and unpublished literature in any language. Their search was for direct evidence on COVID-19 and indirect evidence on related coronaviruses causative of Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS).

While no randomized control trials were found addressing the three coronaviruses, they included 44 relevant comparative studies in healthcare and community settings across 16 countries and six continents from inception to early May 2020.The studies involved nearly 26,000 patients.

Results indicate that transmission of viruses was lower with physical distancing of one meter or more, compared with a distance of less than a meter (n=10 736, pooled adjusted odds ratio [aOR] 0·18, 95% CI 0·09 to 0·38; risk difference [RD] −10·2%, 95% CI −11·5 to −7·5; moderate certainty) Researchers point out that protection was increased as distance was lengthened (change in relative risk [RR] 2·02 per m; p_interaction=0·041; moderate certainty).

“Face mask use could result in a large reduction in risk of infection (n=2647; aOR 0·15, 95% CI 0·07 to 0·34, RD −14·3%, −15·9 to −10·7; low certainty), with stronger associations with N95 or similar respirators compared with disposable surgical masks or similar (e.g., reusable 12–16-layer cotton masks; p_interaction=0·090; posterior probability >95%, low certainty),” the authors write. “Eye protection also was associated with less infection (n=3713; aOR 0·22, 95% CI 0·12 to 0·39, RD −10·6%, 95% CI −12·5 to −7·7; low certainty). Unadjusted studies and subgroup and sensitivity analyses showed similar findings.”

Conclusions support physical distancing of one meter or more and provide quantitative estimates for models and contact tracing to inform policy, the authors explain, adding, “Optimum use of face masks, respirators, and eye protection in public and health-care settings should be informed by these findings and contextual factors. Robust randomized trials are needed to better inform the evidence for these interventions, but this systematic appraisal of currently best available evidence might inform interim guidance.”

The authors note that large randomized trials on the use of masks are underway and more are urgently needed.

"There is an urgent need for all caregivers in health-care settings and non-health-care settings to have equitable access to these simple personal protective measures, which means scaling up production and consideration about repurposing manufacturing," explained lead author Derek Chu, PhD, a clinician scientist in the departments of health research methods, evidence, and impact, and medicine at McMaster and an affiliate of the Research Institute of St. Joe's Hamilton.

"However, although distancing, face masks, and eye protection were each highly protective, none made individuals totally impervious from infection and so, basic measures such as hand hygiene are also essential to curtail the current COVID-19 pandemic and future waves."