Rapid review of the effects of cloth and medical masks for preventing transmission of SARS-CoV-2 in community and household settings

Abstract

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is spread from person to person, predominantly through respiratory droplets and contact with contaminated surfaces, [1] and possibly through airborne transmission. [2] Consequently, close contact with infected people should be avoided. Transmission risk may be mitigated by wearing personal protective equipment (PPE) such as face masks. The pandemic has led to global shortages of PPE, including masks and respirators. Masks are critical to protecting healthcare workers from becoming infected and from infecting patients. [1] Masks have also been widely promoted for preventing transmission in community settings. This is particularly relevant for SARS-CoV-2, since pre-symptomatic transmission may be important. [3] Guidance from global oversight bodies varies. At the start of the pandemic, the World Health Organization (WHO) noted in April 2020 that there was insufficient evidence to support mask use, with uncertainties about risks for healthy people in the community setting. [1] The WHO offered advice to decision-makers to consider the following before using masks in communities: (i) the rationale and reason for mask use must be clear; (ii) SARS-CoV-2 exposure risk in the community; (iii) population vulnerability to develop severe disease or mortality risk; (iv) population setting and ability to implement social distancing; (v) feasibility in terms of mask use costs, availability and tolerability; and (vi) mask type. The potential risks should also be considered, particularly diversion of medical mask supplies from essential service personnel such as healthcare providers. Regarding non-medical cloth masks, the WHO advised in June 2020 that decision-makers apply a risk-based approach and recommended the use of these masks in some situations such as in communities with widespread transmission and when there's limited space for physical distancing. Cloth masks should be used together with handwashing, cough and sneezing etiquette, and physical distancing as key to reducing transmission. [1] The US Centers for Disease Control and Prevention (CDC) changed its guidance on 6 April 2020 regarding mask use for the general public by issuing a directive to 'cover your mouth and nose with a cloth face cover when around others'. [4] For healthcare workers, they recommended the use of homemade masks as a last This open-access article is distributed under Creative Commons licence CC-BY-NC 4.0.