Postdoctoral fellow at the Faculty of Medicine at the University of Vermont, the physicist and member of the Covid-19 Observatory Vitor Mori says that, since the beginning of the pandemic, Brazil should have already invested in offering the N95 mask (PPF2) to the population that is more exposed to the virus. “Brazil made a mistake in the containment and was more concerned with the larger droplets, with the surfaces, but we know about the inhalation infection of small droplets, by the aerosols, and it cost many lives. To go in this direction now is to recover a delay of nine months. “
According to Mori, fabric masks were temporary solutions, although they can be used for outdoor locations that allow social distance. For risky situations, the correct thing would be to adopt the N95. “In closed, poorly ventilated, crowded environments, such as going to the hospital or health center, in crowded public transport. It is a conscious use”, he exemplifies.
Mori explains that PFF2 has an electrostatic filtering layer, which induces a charge and attracts aerosol particles to the filter. “They can filter 94% of the particles that are 0.3 micrometers in diameter.” However, the use must be correct. Otherwise, the effectiveness of the protection will be affected. “PFF2 adjusts well to the face, with virtually no air leakage. It has to be very tight to the face, with the elastic attached to the head and neck. The air cannot pass through the side. There is no point in the filter being good and the air pass”.
These masks are disposable, but, during the pandemic, their reuse came to be considered as possible in view of the scarcity of the product, which is used by health professionals who work on the front lines in the fight against the disease. “Theoretically, in the ideal scenario, without a pandemic and without a lack of supplies, it should only be used once. But people can use it as many times as possible so as not to be missed by health professionals. As long as the mask is complete, with the intact filter mat, without panels peeling off, you can reuse it. “
He warns that the mask cannot be washed or cleaned with alcohol, as this damages the electrostatic layer. “After use, it should be hung out of direct sunlight and can be used again after at least three days.”
The National Health Surveillance Agency (Anvisa) published this month recommendations on the mask in which it mentions the reuse of the product, but emphasizing that it is aimed at health professionals. ” The recommendation is that respirators be reused by the same employee as long as they maintain their structural and functional integrity and the filter is not dirty or damaged.”
For Alexandre Naime Barbosa, consultant at the Brazilian Society of Infectious Diseases (SBI) and coordinator of the Infectious Diseases Department at the Universidade Estadual Paulista (Unesp) in Botucatu, the idea of using the N95 mask is to improve protection in the face of new variants, but transmission by aerosol is not the main form of infection and Brazil needs to follow basic recommendations before evaluating the use of this model by the population.
He explains that the N95 has an additional protective factor, which is to avoid aerosol transmission, a transmission not so frequent in covid-19, because it occurs more in a hospital environment, where there is aerosol due to intubation, when it is fogging. On a daily basis, says Barbosa, the most important transmission is by droplet when talking, coughing, sneezing nearby.
WITHOUT THE BASIC
“If we have to do something to change the situation, it is to follow the protection measures that are already classic: wearing a mask, social distance and hand hygiene. So, this is an extra care that the countries of Europe are doing, but , maybe, we are not doing the basic homework. For several reasons, this is not the main concern, nor does this discussion fit in Brazil. We are having agglomeration. We do not even follow the basics. “