On June 5, 2020, the World Health Organization (WHO) issued updated interim guidance on the use of masks in the context of COVID-19.
The updated interim guidance includes the following recommendations:
In the absence of aerosol generating procedures (AGPs), WHO recommends that health workers providing direct care to COVID-19 patients should wear a medical mask (in addition to other personal protective equipment [PPE] that are part of droplet and contact precautions). Medical masks are defined as surgical or procedure masks that are flat or pleated; they are affixed to the head with straps that go around the ears or head or both. Their performance characteristics are tested according to a set of standardized test methods that aim to balance high filtration, adequate breathability, and optionally, fluid penetration resistance.
In care settings for COVID-19 patients where AGPs are performed (e.g. COVID-19 intensive and semi-intensive care units), WHO recommends that health workers should wear a filtering facepiece respirator (FFR; N95 or FFP2 or FFP3 standard, or equivalent).
The WHO also provides guidance for mask use by the general public. Non-medical masks should have a minimum of three layers, depending on the fabric used; the guidance document contains detailed recommendations on materials and construction. Non-medical masks are encouraged in the following settings:
Areas with known or suspected widespread transmission and limited or no capacity to implement other containment measures such as physical distancing, contact tracing, appropriate testing, isolation and care for suspected and confirmed cases: public settings, such as grocery stores, at work, social gatherings, mass gatherings, closed settings, including schools, churches, mosques, etc.
Settings with high population density where physical distancing cannot be achieved, and/or surveillance and testing capacity and isolation and quarantine facilities are limited; e.g., refugee camps, camp-like settings etc.
Settings where a physical distancing cannot be achieved: general public on transportation (e.g., on a bus, plane, train); specific working conditions which places the employee in close contact or potential close contact with others e.g., social workers, cashiers, servers.
Vulnerable populations (people aged ≥ 60 years; people with underlying comorbidities, such as cardiovascular disease or diabetes mellitus, chronic lung disease, cancer, cerebrovascular disease, immunosuppression) are encouraged to wear a medical mask in settings where physical distancing cannot be achieved. The WHO recommends that persons with any symptoms suggestive of COVID-19 should wear a medical mask, self-isolate, and seek medical advice as soon as they start to feel unwell with potential symptoms of COVID-19.
World Health Organization (WHO). Advice on the use of masks in the context of COVID-19: Interim guidance 5 June 2020. Available at: click here. Accessed June 6, 2020.