WebMD - Face Shields May Be Next Step to Prevent COVID
May 29, 2020 -- Face masks have become commonplace in the effort to combat COVID-19, but some doctors say it is time to take protection a step further and try full face shields as restrictions slowly begin to loosen.
Face shields are nothing new in medical settings -- doctors and nurses who treat coronavirus patients are using them along with standard face masks. Health care professionals are split on whether they should also be worn by children, teachers, and in offices while states reopen.
“Face shields appear to have a number of advantages: They’re easy to wear correctly and good at blocking droplets,” says Eli Perencevich, MD, an infectious disease doctor at the University of Iowa and the Iowa City Veterans Affairs Health Care System. “They’re really a better option for protection.”
Perencevich and his colleagues published a report in JAMA last month, arguing that face shields have more COVID-fighting potential than standard masks when used with increased testing, contact tracing, and social distancing.
A few things make shields superior, he says. For one, many people wear masks that don’t fit well, so they don’t work as well. They also prompt people to touch their faces more, increasing the risk of viral spread. They leave much to be desired in terms of comfort, he says, and they make it harder to breathe.
Shields come with the perk of being easily sanitized and reused, says Keith Kaye, MD, a professor of medicine and director of research for the division of infectious diseases at the University of Michigan Medical School.
Unlike masks, clear shields also allow for better communication -- people can read facial expressions, and those who are hearing impaired can read lips, he says.
“I do think we're going to see more and more face shield use,” Kaye says. “Particularly as COVID continues to cause problems.”
While there is not a lot of data on how well masks work, one recent study in China found that wearing a mask at home reduced transmission to other members of the same household by nearly 80%.
Shields, meanwhile, have been found to successfully block droplets. One cough simulation study in 2014 found that a shield may reduce exposure by 96% when worn within 18 inches of someone coughing.
In addition, face masks are not meant to protect the wearer -- they leave other vulnerable parts of the face exposed, like the eyes. They are meant to keep an asymptomatic or pre-symptomatic person from spreading it to others.
But not all doctors are sold on everyday use of more extreme protective gear. Dan Kuritzkes, MD, chief of infectious diseases at Brigham and Women’s Hospital in Boston, says the eye coverage that shields provide is likely not necessary for people unless they are providing medical care to COVID-19 patients.
“In theory, it may be possible that particles could land in someone’s eye and cause infection, but we don’t have good evidence that happens,” he says. “I think the bottom line is for the general public, there's no reason to be wearing face shields.”
He also says they may not help prevent airborne transmission, because air that has droplets in it could get sucked under the shield from the bottom opening.
Face shields are important in health care settings because, in those situations, mucous membranes around the caregivers’ eyes that could come into contact with harmful droplets while they do procedures like intubation, says Timothy Brewer, MD, a professor of medicine and epidemiology at the UCLA Fielding School of Public Health and Medicine.
As long as everyone abides by recommendations to wear a face mask, that risk won’t exist for non-health care workers.
“It could potentially get in someone’s eyes if someone sneezes -- that's why the person sneezing should also be wearing a mask,” Brewer says.