In areas with community transmission of covid-19, non-medical masks (such as cloth ones) should always be used by the general public in closed places, including shops, workplaces, and schools, if ventilation is not available. adequate or unable to maintain a physical distance of at least one meter. This is stated by the WHO in the latest update of its guide on masks.
Although the distance can be maintained, if the ventilation does not meet the requirements of national institutions regarding the SARS-COV2 virus in terms of temperature and humidity, for example, masks should always be used as a preventive measure.
In areas with covid-19, masks should always be used in closed places such as shops, workplaces and schools if there is not adequate ventilation or a distance of at least one meter cannot be maintained.
In outdoor locations, the Organization maintains its recommendation to use non-medical, fabric, three-layer masks with a filter in the middle, if it cannot be stored at least one meter away.
Not recommended with valves
In the new guide, experts advise against the use of those face coverings that have valves, commonly used by construction workers.
“The danger is that if you wear a mask with a valve and you are infected, you may be expelling infected aerosols. In other words, you miss the point of wearing a mask. It’s not dangerous for you, but it just defeats the purpose, ”explains WHO emergency director Michael Ryan.
This body recalls that the use of masks is part of a comprehensive package of prevention and control measures to limit the spread of SARS-CoV-2, but insists that only one mask, even when used correctly, is insufficient to provide a adequate protection or source control.
Other infection prevention and control measures include hand hygiene, physical distance of at least one meter, avoiding touching the face, covering when coughing or sneezing, adequate ventilation indoors, as well as testing, tracking of contacts, quarantine and isolation.
Together, these measures are essential to prevent person-to-person transmission of the disease.
Use of masks at home
It is recommended to wear masks at home when a visitor comes and the ventilation is poor
WHO recommends using masks at home when there is a non-household visitor and ventilation is known to be poor, with limited opening of windows and doors for natural ventilation, or when the ventilation system cannot be assessed or is not working. correctly, regardless of whether a physical distance of at least one meter can be maintained.
They should also be used inside homes that, although they have adequate ventilation, the safety distance of at least one meter cannot be maintained.
Masks during physical exercise
They should not be used during vigorous intensity physical activity as they can reduce the ability to breathe comfortably, but it is necessary to maintain a safe distance and ventilate
The WHO advises that people should not wear masks during vigorous-intensity physical activity as they can reduce the ability to breathe comfortably. The most important preventive measure is to maintain a distance of at least one meter and ensure good ventilation during exercise.
If the activity takes place indoors, adequate ventilation must be ensured at all times by natural ventilation or an artificial system that is properly functioning or maintained.
Special attention should be paid to cleaning and disinfecting the environment, especially high-contact surfaces. If all of the above measures cannot be guaranteed, consider temporarily closing public indoor exercise facilities, such as gyms, for example.
Use of masks in children
The Organization reiterates its position that children under the age of five should not wear masks, and that the decision to use them by those between 6 and 11 years old should be based on a risk approach.
Children under 5 years old should not use masks, it must be assessed for those between 6 and 11 according to the circumstances, and adolescents 12 years and older have to follow the same instructions as for adults
Factors to consider in this age range include the intensity of SARS-CoV-2 transmission in the community, the child’s ability to comply with the appropriate use of the mask and the availability of adequate adult supervision, as well as the local social and cultural environment and specific settings, such as homes with elderly relatives or schools.
However, teens 12 and older should follow the same guidelines that are given to adults.
WHO emphasizes that special considerations are required for immunosuppressed children or for pediatric patients with cystic fibrosis or certain other diseases (eg cancer), as well as for minors of any age with developmental disorders, disabilities or other specific health conditions that may interfere with the use of the mask.
Recommended masks with three layers
Industrially manufactured masks must meet minimum thresholds related to three essential parameters: filtration, breathability and fit. They come in different shapes, such as flat-folded or ‘duck-billed’ shapes, and you have to choose the one that best fits your nose, cheeks and chin.
Fabric masks, even if they are homemade, have to have three layers: an internal hydrophilic or absorbent (eg cotton), an external hydrophobic (polyester) and an intermediate layer that improves filtration (polypropylene)
In the case of fabric masks, even if they are homemade, the WHO recommends the structure with three layers (depending on the fabric used), since each one has its function: an inner layer of hydrophilic or absorbent material (such as cotton), an external one with non-absorbent hydrophobic material (such as polyester) and an intermediate hydrophobic one (polypropylene, for example), which improves filtration and retains droplets.
The WHO insists on advising against exhalation valves because they bypass the filtration function of the cloth mask, rendering it useless.
Use of masks or faceshields
Face shields or goggles only provide eye protection
Masks, visors or faceshields provide a level of eye protection only and should not be considered an equivalent to masks with respect to protection against respiratory droplets. Current laboratory testing standards only evaluate these face shields for their ability to protect the eyes from chemical splashes.
In the context of unavailability or difficulties in the use of a non-medical mask (in people with cognitive, respiratory or hearing impairments, for example), face shields can be considered as an alternative, noting that they are inferior to masks in terms of transmission and prevention. If face shields are to be used, ensure that the design is suitable to cover the sides of the face and under the chin.
Correct use and care of masks
For any type of mask, proper use, storage and cleaning or disposal are essential to ensure that they are as effective as possible and avoid an increased risk of transmission. Sometimes there may be doubts in following the correct handling practices for masks, which, according to the Organization, reinforces the need to give the appropriate messages.