Coronavirus disease (COVID-19): Masks

Wearing a mask reduces the spread of respiratory illnesses within the community by  reducing the number of infectious particles that may be inhaled or exhaled. These particles may be spread when an infected individual talks, sings, shouts, coughs, or sneezes (even if not symptomatic).

Hence, masks may provide protection to the wearer and those around them. 

Masks are one component of a package of prevention and control measures to limit the spread of COVID-19. In addition to mask wearing, these measures include avoiding crowded spaces, avoiding poorly ventilated spaces and improving ventilation in indoor spaces, keeping a distance, hand hygiene, respiratory etiquette - covering your mouth and nose with a bent elbow or a tissue when you cough or sneeze, getting vaccinated and staying up to date with booster doses. 

Be supportive of others wearing a mask if they choose to.  

To help reduce the spread of COVID-19, WHO recommends wearing a mask: 

• When in a crowded, enclosed or poorly ventilation area (eg. you are unable to maintain distance). If you have any doubts regarding the quality of ventilation, wear a mask.
• If you have or think you might have COVID-19, when sharing a space with others:
  • If you feel unwell and have any of the signs and symptoms suggestive of COVID-19
  • If you recently tested positive for COVID-19 with or without symptoms
  • If you recently had contact (exposure) to someone who has tested positive for or displays symptoms of COVID-19
• When sharing a space with someone who has symptoms of COVID-19 or is COVID-19 positive
• When you are in a public space, and you are at high risk of becoming seriously ill with COVID-19 or dying. For example, if you have underlying health conditions (such as diabetes, heart or lung disease, cancer, immunosuppression, history of stroke and/or asthma) or if you are 60 years or older.

In other situations, not included in the above, you should assess your individual risk to determine if a mask should be worn. When deciding to wear a mask or not, the following should be considered:

• If COVID-19 infections are increasing in your community or there is an increase in those being hospitalized for COVID-19
• When your community has low levels of population immunity (such as low vaccination coverage)
• The overall status of your health

There are three types of masks that WHO recommends for the public: 

• disposable medical masks*; 
• non-medical masks that comply with standards for safety and efficacy and can be washed prior to reuse;
• if the above options are not available, other types of well-fitting non-medical masks are an acceptable option (according to local policies).

*Look for disposable medical masks labelled with any of the following standard certifications: ASTM F2100, EN 14683, YY 0469, YY/T 0969, GB 19083, or ASTM F3502. For more information on acceptable mask type, see the guideline, infection prevention and control in the context of COVID-19: a living guideline

Filtration, breathability and fit are all important.

If you purchase a non-medical mask, check the labels to make sure it complies with the ASTM F3502 standard or CEN/TS17553.

If you choose to make your own mask, it should be made of three layers of fabric:

• Inner layer of absorbent material, such as cotton.
• Middle layer of non-woven non-absorbent material, such as polypropylene.
• Outer layer of non-absorbent material, such as polyester or polyester blend.

Watch the video on WHO’s recommended fabric mask materials and composition for more information.

For either type of mask, you should choose the one that fits your face well - cover your nose, cheeks and chin without leaving gaps on the sides. Masks with vents or exhalation valves are not advised because they allow unfiltered breath to escape the mask.

How to put on and take off a medical mask:

• Before touching the mask, clean your hands with an alcohol-based hand rub or soap and water.
• Inspect the mask for tears or holes; do not use a mask that has previously been worn or is damaged.
• Verify which side is the top – this is usually where the metal strip is.
• Then, identify the inside of the mask, which is usually the white side.
• Place the mask on your face covering your nose, mouth and chin, making sure that there are no gaps between your face and the mask. Place the straps behind your head or ears. Do not cross the straps because this can cause gaps on the side of the mask.
• Pinch the metal strip so it moulds to the shape of your nose.
• Remember, do not touch the front of the mask while using it to avoid contamination; if you accidentally touch it, clean your hands.

How to take off a medical mask:

• Before touching the mask, clean your hands with an alcohol-based hand rub or soap and water.
• Remove the straps from behind the head or ears, without touching the front of the mask.
• As you remove the mask, lean forward and pull the mask away from your face. 
• Medical masks are for single use only; discard the mask immediately, preferably into a closed bin.
• Clean your hands after touching the mask.
• Be aware of the condition of the mask; replace it if it gets soiled or damp.

How to put on and wear a fabric mask:

• Before touching the mask, clean your hands with an alcohol-based hand rub or soap and water.
• Inspect the mask for tears or holes, do not use a mask that is damaged.
• Adjust the mask to cover your mouth, nose, and chin, leaving no gaps on the sides.
• Place the straps behind your head or ears. Do not cross the straps because this can cause gaps on the side of your face.
• Avoid touching the mask while wearing it. If you touch it, clean your hands.
• Change your mask if it gets dirty or wet.

How to take off and store a fabric mask:

• Clean your hands before taking off the mask.
• Take off the mask by removing it from the ear loops, without touching the front of the mask.
• If your fabric mask is not dirty or wet and you plan to reuse it, put it in a clean resealable bag. If you need to use it again, hold the mask at the elastic loops when removing it from the bag. Clean your mask once a day.
• Clean your hands after removing the mask.

How to clean a fabric mask:

• Wash fabric masks in soap or detergent and preferably hot water (at least 60 degrees Centigrade/140 degrees Fahrenheit) at least once a day.
• If it is not possible to wash the mask in hot water, then wash it in soap/detergent and room temperature water, followed by boiling the mask for 1 minute.

Watch our ‘How to wear a fabric mask’ video for a demonstration.

Even when you’re in an area with active COVID-19 transmission, masks should not be worn during vigorous physical activity because of the risk of reducing your breathing capacity. No matter how intensely you exercise, keep at least 1 metre away from others, and if you’re indoors, make sure there is adequate ventilation.

If COVID-19 is widely circulating and impacting the health system, visitors, along with health and care workers and caregivers, should always wear a well-fitting medical mask in all common areas and when caring for non-COVID-19 patients.

Health and care workers caring for COVID-19 patients should wear a respirator or a medical mask. A mask may be required for inpatients if in close contact with a health and care worker, for example during examinations or bedside visits, and when the patient is outside of their care area when being transported.

When caring for a suspected or confirmed COVID-19 patient, a respirator or a medical mask should be worn by health and care workers along with other personal protective equipment (PPE) – gown, gloves and eye protection. Factors for informing the choice in mask type may include a risk assessment and health and care workers’ values and preferences. Health and care workers may choose to wear a respirator in healthcare facilities where ventilation is known to be poor or cannot be assessed, or the ventilation system is not properly maintained.

A respirator should always be worn along with a gown, gloves, and eye protection by health and care workers performing aerosol-generating procedures (AGP) and on duty in settings where AGP are regularly performed on patients with suspected or confirmed COVID-19, such as intensive care units, semi-intensive care units or emergency departments.

Health and care workers must remember to combine hand hygiene with any time they touch their respirator or medical mask or face, before and after putting on and removing them, as well as before they touch them to readjust them.

Further resources:

• Healthcare workers can consult our OpenWHO course on how to put on and remove personal protective equipment.

• For more information on IPC in the context of COVID-19, see: Infection prevention and control in the context of coronavirus disease (COVID-19): A living guideline 

Health workers, caregivers and visitors must perform hand hygiene any time they touch their medical mask or face, before and after putting on and removing them, as well as before they touch them to readjust them.

Medical masks (also known as surgical masks) are:

• composed of 3 layers of synthetic nonwoven materials
• configured to have filtration layers sandwiched in the middle
• available in different thicknesses
• have various levels of fluid-resistance and filtration.

Respirators (also known as filtering facepiece respirators – FFP) are available at different performance levels such as FFP2, FFP3, N95, N99, N100.

Medical masks and respirator masks are similar in their filtration value. However, respirators also have a tight fit around the wearer face as the model and size of the respirator is specific to the wearer to ensure an adequate seal.

Health and care workers should be fit tested before using a respirator to ensure that they are wearing the correct size. Wearing a loose-fitting respirator will not offer the same level of protection to the wearer as it may allow small particles to get inside the mask where there are gaps, for example through the side.