Use of masks in the community:WHO

Background

This document provides rapid advice on the use of medical masks in communities, at home, and in health care facilities in areas that have reported outbreaks of COVID-19. It is intended for public health and infection prevention and control (IPC) professionals, health care managers, health care workers, and community health workers. It will be revised as more data become available. Current information suggests that the route of human-to-human transmission of COVID-19 is either via respiratory droplets or contact. Any person who is within 1 metre (in close contact) of someone who has respiratory symptoms (e.g. sneezing, coughing, etc.) is at risk of being exposed to potentially infective respiratory droplets. Medical masks are surgical or procedure masks that are flat or pleated (some are shaped like cups); they are affixed to the head with straps..

General advice

Wearing a medical mask is one of the prevention measures that can limit the spread of certain respiratory diseases, including COVID-19. However, the use of a mask alone is insufficient to provide an adequate level of protection, and other measures should also be adopted. If masks are used, they must be combined with hand hygiene and other IPC measures to prevent human-to-human transmission of COVID-19. WHO has developed guidance for home care1 and health care settings2 on IPC strategies for use when COVID-19 is suspected. Wearing medical masks when not indicated may result in unnecessary costs and procurement burdens and create a false sense of security that can lead to the neglect of other essential measures, such as hand hygiene practices. Further, using a mask incorrectly may hamper its effectiveness in reducing the risk of transmission.

Community settings

Individuals without respiratory symptoms should:

• avoid groups of people and enclosed, crowded spaces;
• maintain distance of at least 1 meter from any person with respiratory symptoms (e.g. coughing, sneezing);
• perform hand hygiene frequently, using an alcohol-based hand rub if hands are not visibly dirty or soap and water when hands are visibly dirty;
• cover their nose and mouth with a bent elbow or paper tissue if coughing or sneezing, dispose of the tissue immediately after use, and perform hand hygiene;
• refrain from touching their mouth and nose. A medical mask is not required for people who are not sick as there is no evidence of its usefulness in protecting them.

However, masks might be worn in some countries, in accordance with local cultural habits. If masks are used, best practices should be followed about how to wear, remove, and dispose of them, and for hand hygiene after removal.

Individuals with respiratory symptoms should:

• wear a medical mask and seek medical care as soon as possible if they have fever, cough, and difficulty breathing;
• follow the advice below regarding appropriate mask management.

Home care

WHO recommends that all laboratory confirmed cases be isolated and cared for in a health care facility. WHO recommends that all persons with suspected COVID-19 who have severe acute respiratory infection be triaged at the first point of contact with the health care system and that emergency treatment should be started based on disease severity. WHO has updated treatment guidelines for patients with ARI associated with COVID-19, which includes guidance for vulnerable populations (e.g., older adults, pregnant women and children). In situations where isolation in a health care facility of all cases is not possible, WHO emphasizes the prioritization of those with highest probability of poor outcomes: patients with severe and critical illness and those with mild disease and risk for poor outcome (age >60 years, cases with underlying co-morbidities, e.g., chronic cardiovascular disease, chronic respiratory disease, diabetes, cancer). If all mild cases cannot be isolated in health facilities, then those with mild illness and no risk factors may need to be isolated in non-traditional facilities, such as repurposed hotels, stadiums or gymnasiums where they can remain until their symptoms resolve and laboratory tests for COVID-19 virus are negative. Alternatively, patients with mild disease and no risk factors can be managed at home. Home care may also be considered when inpatient care is unavailable or unsafe (e.g. capacity is limited, and resources are unable to meet the demand for health care services).

Specific IPC guidance for home care should be followed.

Persons with suspected COVID-19 and mild respiratory symptoms should:

• Perform hand hygiene frequently, using an alcohol-based hand rub if hands are not visibly dirty or soap and water when hands are visibly dirty;
• Keep a distance of at least 1 metre from other people;
• Use a medical mask; the mask should be provided to the individual and worn for as long as possible, if it can be tolerated, and changed at least once daily. Persons who cannot tolerate a medical mask should rigorously apply respiratory hygiene (i.e. cover mouth and nose with a disposable paper tissue when coughing or sneezing and dispose of it immediately after use, and then perform hand hygiene.)
• Improve airflow in their living space by opening windows and doors as much as possible.

Caregivers or those sharing living space with persons with mild respiratory symptoms and suspected COVID-19 should:

• Perform hand hygiene frequently, using an alcohol-based hand rub if hands are not visibly dirty or soap and water when hands are visibly dirty;
• Keep a distance of at least 1 meter from the affected person when possible;
• Wear a medical mask when in the same room as the affected person;
• Dispose of any material contaminated with respiratory secretions (disposable tissues) immediately after use and then perform hand hygiene.
• Improve airflow in the living space by opening windows as much as possible.

Health care facilities

Individuals with respiratory symptoms should:

• Wear a medical mask while waiting in triage or other areas and during transportation within the facility;
• Wear a medical mask when staying in areas dedicated to suspected or confirmed cases;
• Not wear a medical mask when isolated in single rooms, but they should cover their mouth and nose when coughing or sneezing with disposable paper tissues. Tissues must be disposed of appropriately, and hand hygiene should be performed immediately afterwards.

Health care workers should:

• Wear a medical mask when entering a room where patients with suspected or confirmed COVID-19 are admitted;
• Use a particulate respirator at least as protective as a US National Institute for Occupational Safety and Health-certified N95, European Union standard FFP2, or equivalent, when performing aerosol-generating procedures, such as tracheal intubation, non-invasive ventilation, tracheotomy, cardiopulmonary resuscitation, manual ventilation before intubation, and bronchoscopy.

Mask management

• If medical masks are worn, appropriate use and disposal are essential to ensure they are effective and to avoid any increase in transmission. The following information on the correct use of medical masks is derived from practices in health care settings
• Place the mask carefully, ensuring it covers the mouth and nose, and tie it securely to minimize any gaps between the face and the mask.
• Avoid touching the mask while wearing it.
• Remove the mask using the appropriate technique: do not touch the front of the mask but untie it from behind.
• After removal or whenever a used mask is inadvertently touched, clean hands using an alcohol-based hand rub or soap and water if hands are visibly dirty.
• Replace masks as soon as they become damp with a new clean, dry mask.
• Do not re-use single-use masks.
• Discard single-use masks after each use and dispose of them immediately upon removal.
• Cloth (e.g. cotton or gauze) masks are not recommended under any circumstances.

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Ref:
1. World Health Organization. Home care for patients with COVID-19 presenting with mild symptoms and management of contacts: interim guidance (accessed 29 January 2020).
2. World Health Organization. Infection prevention and control during health care when COVID-19 is suspected: interim guidance (accessed 29 January 2020).