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Proper use of a mask reduces the risk of contagion. UIS professor leads scientific report

Image Laura Rodírguez. PhD in epidemiology
Image Laura Rodírguez. PhD in epidemiology

Due to a new wave of COVID-19 infections caused by the Omicron variant, two health professionals reiterate some specific guidelines on the use of masks or face masks as a preventive measure to avoid the transmission of the SARS-CoV-2 virus and make it clear that it is not the time to lower our guard.

This is how the physician Laura Rodríguez, PhD in epidemiology and professor of the Public Health Department of the Universidad Industrial de Santander (UIS), in a joint work with members of the Environmental and Occupational Health Node (SAO) of Colombia, and the physician Leonardo Briceño Ayala, professor of the Universidad del Rosario, released some specific guidelines on the correct use of masks.

“Despite the fact that we are about to complete two years of pandemic, many people still do not know how to use the mask properly; others do not even use it. Let’s remember that the virus is still among us and it is everyone’s duty to take care of ourselves, both individually and collectively,” said physician Laura Rodriguez.

Consistent and proper use of the mask

The main transmission of the virus is through airborne aerosols. Masks are a mechanism to prevent contagion, because they reduce the dissemination and inhalation of aerosols and therefore the transmission of COVID-19 through the air. Therefore, it should be worn in all places when outside the home or inside the home, if living with someone with symptoms.

The mask should cover nose, mouth and chin, be tight fitting and should be handled only from the straps and not from the surface of the mask.

N95: has the capacity to filter at least 95% of all aerosols of different sizes.

FFP2: have an approximate filtering capacity of 94% of airborne particles.

The advantages of these two types of respirators consist of a very good filtration of the surrounding air and an appropriate face seal that offers protection to exposed persons and decreases the dispersion of viral particles from contagious persons.

KN95: is the Chinese-made version of 95% filtration respirators. Beware of counterfeit copies that do not offer adequate protection.

KF94: is a South Korean-made respirator with at least 94% filtration.

In health workers, N99, FFP3, N95 and FFP2 masks are the most widely recommended and their use in most developed countries is the norm due to the efficiency characteristics mentioned above.

Surgical masks: Surgical masks offer aerosol filtration in the range of 70% -80% which is variable as they are not standardized.

Cloth masks: Cloth masks have the lowest or no particle filtration capacity. Even with the best ones that include 3 layers, the filtration capacity of viral particles is between 0 and 25%.

Mask fit: you should make sure that the mask adheres to your face when you take in air (inhale) and expands when you expel air (exhale). When exhaling air, you should not feel air in your eyes and therefore the blinking reflex should not occur. If you blink when exhaling, it is because you have an air leak.

Which mask should be used?

It depends on the place and type of activities to be developed. For outdoor activities, where you will not have close contact with other people, the use of surgical or cloth masks may be an acceptable option.

For indoor activities (indoor spaces such as work, educational, commercial or recreational spaces), the recommendation is to use high efficiency masks with higher filtration. In addition, continuing with the vaccination schedule, avoiding closed and poorly ventilated spaces, isolating symptomatic or asymptomatic persons in contact with a positive case, continue to be the main recommendations of the experts.