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People who wear face visors instead of masks to protect themselves from Covid-19 may be at higher risk of contracting the disease, and older people are particularly vulnerable, warned one of the state’s leading virologists.
Dr Kim Roberts of Trinity College Dublin said that the visors “do not protect people in any significant way” and are only useful if used in conjunction with face masks and not in place of them.
He noted that many older people have chosen to wear face shields in recent months over masks because they are perceived to be more comfortable and easier to handle and because they prevent the glasses from fogging up.
“The real danger from that is that wearing a visor can give a vulnerable person a false sense of security,” Dr. Roberts said. “There are many people who use them to protect themselves, although none of the data suggests that viewers do that. They just don’t do the same job as masks. “
He also noted that while in some circumstances it might be beneficial for virus-carrying droplets to be directed downward by viewers, that can also be a significant negative, particularly in a restaurant if a server is standing over a diner or on dishes. of food.
Studies
International studies have shown that while high-quality N95 face masks block 99 percent of aerosols and surgical masks block 59 percent of aerosols, face shields or visors block only 2 percent of potentially harmful aerosols. .
Dr. Robert’s concerns about the increasing popularity of face shields instead of face masks and their ineffectiveness were echoed by UCD engineer Dr. Kevin Nolan.
The academic has spent the last few months working at Mater Hospital in Dublin implementing various technologies based on light, mirrors and lasers to show how far virus-carrying droplets can travel and how long they can stay in the air.
He has also been able to demonstrate how effective face coverings and visors are. “Face shields just don’t work,” Dr. Nolan told The Irish Times.
Using what is known as Schlieren technology, a physics principle dating back more than a century that relies on high-specification mirrors and light to show the density of fluids and gases and the speed and distance they can move when they people breathe, cough and sneeze. visors have been shown to offer little protection to the wearer.
“The way the visors are designed means that anyone who wears one can easily inhale the aerosols that surround them, as the visors offer virtually no protection,” said Dr. Nolan.
Caution
He also cautioned that people who work in the hospitality sector wear visors, as they can direct the drops towards diners and towards food.
“It is probably better to wear a visor than absolutely nothing, but since the virus is transmitted through drops or aerosols, they can only offer very limited protection as it can travel under a visor and on a person’s face,” he said. Dr. Jack Lambert, professor of medicine and infectious diseases at Mater Hospital, said.
He noted that there are no reliable studies that have pointed to the effectiveness of the scopes in slowing the spread of Covid-19. He also emphasized that he had not seen any data or recommendations from international health authorities suggesting that people wear visors instead of face masks.
“What I do know is that we wear masks in hospitals and we have been doing it for a long time to avoid contamination. We know they work. The best thing, I would say, would be for someone to wear a mask and a visor. “
According to the HSE, for people who “find it difficult to wear a cloth face cover, it is okay to use a full visor or face shield instead. They are not as good as wearing a face cover, but you will still get some level of protection, ”says the official advice.
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