If you wear a face shield during a pandemic, it likely won’t give you a high level of protection against COVID, according to new research from the University of East Anglia.
Today’s study published a comparison of 13 types of face shield In controlled laboratory settings.
In addition to studying face shields in the lab, the research team surveyed people including health workers in middle-income countries (Brazil and Nigeria) about their views on face shields as personal protective equipment.
Professor Paul Hunter, of the University of East Anglia’s Norwich School of Medicine, said: “Face shields have been popular because they do not obstruct breathing, allow more natural contact than face masks and provide protection from water splashes.
“They’ve been used extensively during the COVID pandemic. But until now there hasn’t been a great deal of evidence about how protective they really are – especially considering how people use them in the real world, especially in poorer parts of the world.
“We wanted to learn more about how different styles of face shields protect, both in the lab and in real-world settings.”
University of East Anglia researchers teamed up with staff at the Department of Health and Safety (HSE), the UK’s regulator for workplace health and safety, who tested 13 face shield designs in a controlled lab environment, using a “cough machine” that spews fluorescent droplets onto a mannequin’s heads.
The degree of contamination of the model’s face with simulated cough droplets was rated from most to least.
Dr Julie Brainard, from Norwich Medical School at the University of East Anglia, said: “Laboratory testing has shown that all face shields offer some protection, but none offer high levels of protection against external contamination by droplets. The level of protection provided has been influenced by design characteristics., As well as the way a mannequin’s head had “coughed”.
“We found that large gaps around the sides, and sometimes the bottom or top, allow respiratory droplets from other people to reach the face and that means exposure to potential viruses.
“The shields that offered the most protection were closed across the forehead and extended well around the sides of the face and under the chin.
“It’s important to know that lab experiments in the scenario of someone actively coughing at the wearer of the shield at close range. But the chances of droplets wrapping around the shield on the face from just speaking are much lower.”
To learn more about how face shields are used in a real-world environment, the team surveyed more than 600 people across Nigeria and Brazil, including healthcare staff.
Dr Brainard said: “We wanted to know how users are cleaning, and which things are most important when choosing PPE during the pandemic.
“Unsurprisingly, we’ve found that people want proven protective products that are comfortable, stable on their heads, easy to clean, and don’t look weird.
“This study is important because the acceptance of facial PPE during pandemic It has been studied mostly in wealthier countries such as the United Kingdom or the United States. Our study participants were in Nigeria and Brazil and we should not assume that people in all countries view facial PPE in the same way.
“It is also important to understand the design features of face shields that can be more or less protective, so that people can choose the most effective designs.
“Finally, we wanted to know how people cleaned reusable face shields – methylated or surgical spirits were common, for example, as was plain water and soap. Some cleaning chemicals may be incompatible with coatings intended to prevent haze formation. Or facilitating quick drying, for example, dust outside and fog inside the armor were occasional problems as well.”
A mixed study on the efficacy and appropriateness of using a face shield as COVID-19 PPE in middle-income countries has been published in the journal American Journal of Infection Control On July 28, 2022.
In a related project, the HSE team tested face shields available for use in the UK. The results of this work, as well as more details about the cough simulator, have been published in the journal Annals of exposure to work and health.
Dr. Brian Crook, a microbiologist on the Health, Safety and Environment team, said, “It is important that people using any type of PPE to protect themselves from infection know its effectiveness, but also its limitations. We are working with the International Standards Committee to write guidance towards a better way to provide that information.”
Mixed methods study on the efficacy and appropriateness of face shield use as COVID-19 PPE in middle income countries, American Journal of Infection Control (2022).
University of East Anglia
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