Filenews 7 January 2022
Concern about the effectiveness of the cloth mask against the coronavirus is expressed by doctors, at a time when the Omicron mutation has catapulted cases worldwide to record levels. Experts are calling on citizens to abandon cloth masks, which may provide reduced protection. Instead they suggest either the combination of a cloth and surgical mask or the use of a mask that provides higher protection.
In a report, the Wall Street Journal cites infectious disease experts who report that cloth masks, comfortable and styled, are capable of blocking larger droplets carrying the virus, but they cannot stop smaller viral aerosols or particles. Already, the Mayo Clinic requires patients and visitors to wear either surgical masks or KN95. On the contrary, anyone wearing a single layer mask, handmade fabric mask, bandana or mask with a ventilation valve, will be asked to wear a high protection mask as a second.
The U.S. Centres for Disease Control and Prevention (CDC) recommends that citizens use a cloth mask with multiple coatings and a dense fibre network, which they apply comfortably, while having an adjustable tip bridge made of wire.
The advantages of N95
THE N95 have a layer of polypropylene filter, which is a type of plastic, which makes them more effective at blocking small particles. Therefore, the extra coating provides a high degree of protection. This is because they have a denser network of fibres than surgical or cloth masks.
The tighter application, along with the electrostatic charge present in their materials, allows for greater efficiency in trapping large particles and aerosols that exhale the wearer. When worn properly, the N95 mask can block up to 95% of the particles that are in the air.
"You have to wear the right type of mask"
Monica Gandhi, a scientist at the University of California says: "If you really want not to be exposed, then you have to wear the right type of mask." Gandhi proposes the N95 masks, which have been certified in the US. It also recommends the KN95, KF94 and FFP2 masks, which have been certified in China, South Korea and Europe respectively. If they are not available, then citizens should wear a double mask, i.e. a fabric one with multiple layers above one surgery.
"If everyone just wears a cloth or a surgical mask, that doesn't make any difference," since Omicron is very contagious, the scientist notes.
At the same time, experts argue that surgical masks of high quality, worn correctly, provide protection. «Every mask is better than no mask at all. But fabric and surgical are not as good as N95 masks," says Ranu Dillon, a doctor at Brigham and Women's Hospital in Boston.
The comparison of effectiveness of masks
The WSJ presents a graph showing the time it takes to transmit an infectious dose of virus from a person sick with Covid to a person wearing a cloth mask, surgical mask, N95 mask or no mask at all.
If neither of them wears a mask, it is very likely that transmission will take place within 15 minutes. If one wears a cloth mask and the second is not wearing a mask, transmission can be done in 20 minutes. If they both wear a surgical mask, it takes an hour to transmit.
With the use of a cloth mask, transmission times are limited from 20 minutes to 3.3 hours, while with the simple surgical mask, from 30 minutes to 5 hours. If, however, both wear KN95 (N95), with proper fit, it may take 25 hours for them to stick to each other.
"Masks of different quality offer different protection
Megan Srinivas, infectious diseases specialists at the University of North Carolina, admits that she and her family members wear the KN95. As she claims, this type of mask has five layers of protection and a better fit, thus preventing the entry and exit of particles. In fact, he recommends these masks to parents who are preparing to send their children to schools. If they are not available, then suggest a disposable surgical mask. "We need to educate people and explain to them that masks of different quality offer different protection," he notes.
For his part, the director of the department of infection prevention at the University of Pittsburgh Medical Center, Graham Schneider, argues that any mask that offers effective sealing and is worn properly, covering the nose and mouth, is protectively effective. However, more data from the CDC is needed on how Omicron spreads, as well as whether the transmission is related to the types of masks. In any case, his concern concerns the number of citizens who do not wear masks of any type.
