Face shields look clunky and even more dystopian than a regular face mask, but I appreciate the concept. If only coronavirus prevention was truly as simple as placing a thin sheet of plastic over your face. While some businesses might let you in with a face shield instead of a mask, the professional medical consensus across the board is that they’re not an appropriate substitute. In fact, the CDC states that they don’t recommend face shields for everyday activities at all.
Still, face shields aren’t entirely useless. At very least, they do provide some barrier between your respiratory particles and someone else’s. They’d probably be most effective in the event someone literally spit in your face, which, y’know, could hypothetically happen. The problem, though, is that most face shields leave plenty of room for particles to escape below or on the sides of the shield. While they’d limit the trajectory of particles directly in front of someone’s nose and mouth, they’d still be able to travel outward.
For the very few people who genuinely, legitimately cannot wear a face mask, a shield might be a “better than nothing” approach. Currently, the CDC recommends that “anyone who is unconscious, incapacitated or otherwise unable to remove the cloth face covering without assistance” shouldn’t wear a cloth face mask. Someone with limited mobility in their arms, for example, could possibly be a better candidate for a face shield, instead. Deaf and hard of hearing folks also benefit from face shields as they allow for lip-reading.
There’s certainly no harm in wearing a face shield in addition to a cloth face mask, so long as it’s properly disinfected after each use. Wearing a face shield might even give an added layer of protection against yourself if you’re prone to touching your face or readjusting your mask. Particularly with children, many of whom might be sent back to school soon, any extra means of prevention is probably not a bad idea.
With these potential benefits in mind, there is some evidence that face shields could be an adequate solution. One recent op-ed published by researchers at the University of Iowa in April touted that, “in a simulation study, face shields were shown to reduce immediate viral exposure by 96 percent when worn by a simulated health-care worker within 18 inches of a cough,” referencing a 2014 study on the topic. However, in that prior study, it was found that face shields only reduced larger particle inhalation in the half-hour following a cough by 23 percent. So while face shields might adequately protect you if someone coughs right in your face, they don’t entirely reduce the possibility of inhaling the particles that linger. Considering that COVID-19 might be airborne beyond six feet of transmission, that’s a pretty significant risk.
Maybe in a few weeks, the CDC will reverse their stance on face shields the same way they did masks. For now, though, it’s probably best to just keep using face masks.