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The Bogotá District urged the population to wear surgical masks and N-95 masks, and not cloth masks (which are generally homemade). The WHO says they are not as effective, but does not rule out their use.
On Wednesday, the Bogotá District recommended to stop using cloth masks and instead wear conventional surgical masks or N95. The Secretary of Government of Bogotá, Luis Ernesto Gómez, was the one who made the request. “We want to make the recommendation to the general population and that is that they begin to use conventional surgical masks or the N95 for those who require it due to their exposure or level of risk,” he said.
Before these new recommendations, which mask is more effective to protect the population from the contagion of COVID-19?
In other countries they followed the same line
The WHO has explained that viruses are naturally susceptible to mutation, but that the changes they undergo do not necessarily change something essential in them.
In these specific cases, initial studies have found no evidence that anything has changed in terms of the severity of the infection. (You may be interested: If there are new variants of SARS-CoV-2, what about the candidate vaccines?)
Although the UK variant has not been confirmed in Colombia, there are countries where new new strains have been confirmed and the population has been asked to wear specific types of masks.
Germany made it mandatory on Tuesday night for people traveling on public transport or in supermarkets to wear medical-style masks: either N95, the Chinese or European equivalent KN95 or FFP2, or a surgical mask.
In the United States, new variants have prompted the use of double masks or the use of “better quality” masks. “The existence of more communicable viruses emphasizes the importance of us improving our game and not doing more of the same, but better of the same,” Tom Frieden, former director of the Centers for Disease Control and Prevention, told Washington. Post.
SARS-CoV-2 infection is predominantly transmitted by respiratory droplets generated when people cough, sneeze, sing, speak, or breathe. In their guidance, the CDC recommends the widespread use of face masks, “specifically non-valve multilayer fabric masks, to prevent transmission of SARS-CoV-2”
How do they work then?
The mask helps reduce the emission of virus-laden droplets and prevents someone else from inhaling them. This is especially true for asymptomatic people, who are believed to be responsible for 50% of transmissions.
According to the CDC, the multiple layers of a mask block the release of exhaled respiratory particles into the environment, along with the microorganisms that these particles carry.
“Not only do cloth masks effectively block most large droplets (ie 20-30 microns and larger) but can also block the exhalation of fine droplets and particles (also known as aerosols) smaller than 10 microns. . The face masks of certain fabrics can block between 50 and 70% of these droplets.
The CDC says in its guide that Americans should wear face masks with “two or more layers of washable and breathable fabric and avoid surgical masks and other face coverings intended for healthcare workers.”
Why, then, are the health authorities in the United States not recommending what the district secretary did? On the one hand, and according to Frieden, because the N-95s are uncomfortable. On the other hand, if people in that country began to buy these masks en masse, there would be a shortage of these medical devices, vital for instrumentation, nurses, doctors, orderlies and a long list of health personnel in the first line of action against the pandemic. .
On whether or not there is a shortage of N-95 masks in Colombia, Lucía Ayala, director of Medical Devices and other Technologies at Invima, there is no shortage of surgical masks or N-95 in the country. “Before the pandemic, there were 80 companies that had a health registration to make face masks. Today there are 102. As for the cloth masks, they have pores and allow bacteria and viruses to escape, so the idea is to use masks that are medical devices ”.
According to the district official, it is advisable to discard the use of cloth masks. “Studies by the Ministry of Health and by experts at the international level definitely suggest us to insist on avoiding the cloth mask, which was essential when there was a shortage and when the general measure was decreed, but at this time, given the availability of imports and permits that the companies in the country that manufacture them have obtained, the general recommendation is to use these masks ”.
In a review of 172 studies on the effectiveness of masks in preventing COVID-19 transmission, published in July in the journal PNAS, non-medical device masks (such as N95s) use materials that obstruct virus particles. , and have been effective in reducing the transmission of respiratory viruses; and places and periods of time where the use of masks is required or widespread have shown substantially less community transmission.
The World Health Organization has carried out studies on homemade cloth masks and, according to that organization’s use guide, “the use of masks made of other materials (for example, cotton or cloth) also known as non-medical masks , in a community setting it has not been well evaluated ”and that“ there is currently no evidence to recommend or not its use ”.
“No mask is perfect, and wearing one is not obvious other public health measures such as physical distancing and good hygiene. “We have to be honest that the best answer is one that requires multiple interventions,” Jennifer Nuzzo, a public health expert at Johns Hopkins University, told the New York Times.
That same media mentioned that, in the case of making or using a cloth mask, HEPA air filters, vacuum cleaner bags and 600-thread-count pillowcases and fabrics such as flannel are effective in preventing the passage of virus droplets. .
Linsey Marr, a Virginia Tech engineering professor who has researched the effectiveness of masks, said the public has better tools to reduce the viral loads that reach the air and the body. “People can make a three-layer mask by cutting a high-efficiency filter, such as a vacuum bag, to fit between two tightly woven fabric masks. Those standard cloth masks can be around 50 percent effective in terms of protecting yourself, “he told the Washington Post.
