Moving from Face Masks to Transparent Face Shields?

Samantha Godwin, a fellow at Yale Law School, posted this to a discussion list, and I thought I'd pass it along (with her permission):

As universities try to work out if and how to reopen in the fall of 2020, many are working off the view that face coverings are essential to slow the transmission of the novel coronavirus and must be used if in-person classes and activities are resumed.

The default face coverings are the opaque cloth masks that have been widely adopted. These are, however, not the only option available to us, and may not be the option that is most conducive to delivering the core educational and academic functions of universities—including intellectually engaging conversations among faculty and students. These purposes may be much better served by the use of transparent face shields as an alternative rather than supplement for opaque face masks.

When considering best practices to adopt, we ought to  keep in mind that current practices are still largely experiments, both experiments in viral transmission management, and social experiments. We should therefore ask questions of alternative methods beyond 'has this been clinically proven more effective than standard face masks for reducing viral transmission?' although preliminarily there seems to be strong evidence that face shields are very effective at preventing transmission. This is not the only relevant question.

I would instead ask the question: what practices best enable us to live with this virus, which will likely be with us for years, without giving up too much of what we value in society and in our communities?

When put to this test, I think face shields are clearly superior to face masks for a number of reasons:

[1.] Interpersonal communication and empathy: When two people interact, each wearing a facemask, they can see only a small portion of the other's facial expressions. Each perceives the other as less empathetic because they are less able to emote or read the others emotions—a phenomena that has been pretty well demonstrated in pre-COVID-19 clinical studies. There also seems to be some evidence that people mostly read positive emotions from the bottom half of people's faces and negative emotions from the top half of people's faces so a society of face mask wearing is a stressed society.

This is not a problem for transparent face shields though—face shields allow for unobstructed display of emotions and non-verbal communication.

Also I've certainly noticed that it can be hard for people to understand me when I'm wearing a face mask, and hard for me to understand people wearing face masks: they seem to interfere with speech recognition in any non-ideal sound-quality situation, even for people with normal hearing. I suspect this would not be as much of an issue with face shields.

[2.] Compliance: I'm not sure about you, but when I walk down the street, or go to take out restaurants or grocery stores, I see lots of people wearing face masks pulled below their chin, overtly defeating their purpose, or at a minimum pulled below their nose, rendering them a symbolic but totally ineffective statement. The reason for this is obvious: face masks are tremendously uncomfortable for extended periods of time, especially when there's heat, humidity, pollen, or you wear glasses. Pretty much every time I glimpse the workplaces of 'essential workers' (like people in kitchens) I see employees not wearing facemasks despite the state order here to do so. They are just not sustainable and we need to plan for a world with real humans with imperfect compliance.

Face shields, on the other hand, are comparatively comfortable if well made: by avoiding direct contact with the wearer's face, they are 'wearable' for a much longer amount of time.

One apparent advantage of cloth face masks over transparent face shields is the ease with which they can be made at home. However, face shields are also much easier to manufacture at home than might be assumed, and can easily be made at home with readily obtainable materials, as seen in a number of youtube videos, including clear soda bottles as seen here.

[3.] Psychological benefits: The COVID-19 viral pandemic is accompanied by two other health pandemics: widespread depression and anxiety from social isolation, and widespread anxiety about catching the virus, even among people who are very low risk and who do not have much interaction with high risk people. Facemasks are understood (correctly) primarily as a means of protecting other people from the wearer, not the wearer from other people (though there is still probably a significant benefit).

Face shields, however, very clearly protect the wearer as well by covering the wearer's eyes and discouraging the wearer from touching their face—this may provide a more anxiety reducing effect for people worried about contracting COVID-19. The ability to smile and effectively express positive, mutual understanding through facial expressions can alleviate the stress of social isolation that many, especially students and other younger people who lack strong social networks, have been experiencing for months. Face shields beat out opaque face masks on both of these psychological hazards of the COVID-19 pandemic.

There is a possible downside to face shields: they look a bit silly whereas face masks can be fashionable. On balance, I think this can be overcome by explaining that face shields are probably more protective for the wearer and facilitate more natural communication and we all thought face masks looked silly a month ago too—but there might be another way to go:

Perhaps we could consider a third alternative that provides more coverage than face shields or face masks and maintains the social advantages of face shields: mosquito net hats. These translucent net hats almost certainly filter large droplets from the wearer and stop large droplets from others (short of perhaps being sneezed on from very close proximity) and they don't have the medicalized silly appearance of face shields (they also look a little silly but we're in the realm of the imperfect). These might be a viable third option, at least worth further study. Floating Doctors proposed mosquito net hats early on as a viable way to mitigate covid-19, albeit mostly as an easy way to avoid touching your face.

After half a semester of online learning, it is clear to many of us that while it might be better than nothing, it is no substitute for in-person, classroom education and meetings. Too many intangibles of face to face communication are lost online, leaving us with a muted, less rewarding, more exhausting mode of teaching and studying.

To get those intangibles back while continuing to practice risk mitigation, we need to think about exactly what kind of face to face interactions work best. On balance, if we decide that face covers are needed in the fall, we should strongly consider insisting on and normalizing transparent or translucent face covers that allow for a full view of each participant's face to make the most of our time in classrooms together.

Prof. Ed Richards (LSU Law) wrote this in response, specifically referring to the paper in the post to which Godwin linked:

The face shield they are working with is interesting. It has much more coverage than the usual face shield. It looks like a good approach. I would like to see more studies that confirm this study's finding about inhaled virus. Earlier tests by NIOSH did not find face masks acceptable PPE for inhaled particles, but they did not find surgical masks acceptable either. That is where the N95 standard and mask came from.

Masks are problematic, no question. Having used a face shield in other, more pleasant circumstances, they do have their own problems. If you are outdoors, they can get hot and uncomfortable, and you cannot put them in your pocket to use when need to. They look much better for indoors. They fog when conditions are right, and the better they fit, as described in the article, the more they fog. That might prevent their use in certain environments, which probably includes some of my classrooms. But outside of fogging, they have real benefits over masks.

The authors note that no studies have yet been conducted to see how well face shields help keep exhaled or coughed virus from spreading outwards from an infected wearer. I would like to see that study done, otherwise adopting face shields turns the entire rational on its head. You predominately wear surgical style masks to protect others. This would imply that everyone would have to shift to face masks, unless studies show that they are equally good at preventing the spread of virus. We are already ignoring this problem by mixing N95 style masks, those with a valve that allows expired air to bypass the mask filter,  with surgical masks. Surgical style masks are designed to protect others, while ventilated masks protect only the user. We are also completely ignoring beards, which makes masks nearly useless for any purpose.