Innovation and Knowledge Sharing Can Transform COVID-19 Infection Prevention Response

There has been a massive and rapid increase in the need for PPE globally because of overwhelmed health systems having to care for large numbers of patients with suspected or confirmed COVID-19. This has been exacerbated by public fear, which has led to panic buying of medical face masks (primarily used to protect others from infections with a droplet mode of transmission) and filtering facepiece half-mask respirators, which include N95 respirators (used to protect the wearer from infections with an airborne mode of transmission).

COVID-19 is thought to be predominantly spread by transmission of respiratory droplets (>5 and <10 μm in diameter), which occurs when people are in close contact (within 1 meter) with others who typically (but not always) have respiratory symptoms such as cough or sneeze or with fomites that have come into contact with an infected person. This is in contrast to infectious diseases such as tuberculosis (TB) or measles, which are spread by airborne transmission of virus suspended in droplet nuclei (<5 μm in diameter), which can remain in the air for prolonged periods of time and can be transmitted over distances greater than 1 meter.⁴

While World Health Organization (WHO) and CDC infection prevention guidance have cited droplet transmission as the primary mode of transmission for COVID-19, current CDC guidelines state that respirators are preferred for the care of patients with known or suspected COVID-19, given the potential for opportunistic airborne transmission.⁵ However, in the setting of respirator shortages, it is recommended that these should be prioritized for HCWs caring for patients with COVID-19 in the context of aerosol-generating procedures or other patients with infections spread by airborne transmission such as TB or varicella until the supply chain is restored. Of note, optimal use of respirators requires fit testing, which is often lacking in nursing homes and outpatient facilities, as well as more widely in resource-limited countries.

Universal masking (use of surgical mask) for HCWs caring for any patient irrespective of symptoms or presenting complaint has also been implemented by many large hospital systems in recent days. Although universal masking adds to the burden of the PPE shortage, in settings with widespread community transmission and given increasing evidence⁶ demonstrating transmission from people with asymptomatic and presymptomatic infection, universal masking may be useful to decrease transmission. However, particularly in the setting of PPE shortages, it is important to understand that surgical masks are designed to be single use and that dampness and frequent adjustment of the mask affects their effectiveness.

As urgent attempts to coordinate and increase PPE manufacture are being made by health systems, in conjunction with private partnerships, there has also been a burst of public campaigns to sew cloth masks to mitigate the real-time shortages. Although it is likely that cloth masks provide inadequate protection in comparison with surgical masks,⁷ evidence does suggest that cloth masks provide some degree of protection from the spread of respiratory viruses,⁸ particularly if these are replaced promptly when damp or damaged and if combined with other interventions such as hand hygiene. This has led to recommendations for the general public in various countries to wear cloth face coverings in public settings, particularly where social distancing may be harder to maintain, but these are not recommended for use by HCWs in healthcare settings.