Now they have been installed on the stage at Wednesday’s 2020 Vice Presidential Debate to shield the participants from each other, but are they effective?
Plexiglass shields and partial walls sound like a good idea -- a solid barrier between two people must do something to protect them from each other -- but many of the extreme measures we’re taking in these days of COVID-19 aren’t necessarily rooted in science and often become hygiene theater.
See-through barriers used to only be seen in banks and other areas where we wanted face-to-face interaction with protection from the person on the other side of the glass, but now they’re everywhere, erected to stop the spread of coronavirus.
Both the Centers for Disease Control and Prevention and Occupational Safety and Health Administration recommend the use of plexiglass and other barriers in work environments to reduce direct spread of potentially infectious droplets between people, especially in manufacturing, retail or food service settings where physical distance might not be consistent.
Even though these recommendations are in place, there is surprisingly little science that supports their use or that gives clear guidance on the best design for them.
Intuitively, a barrier should be effective at stopping droplets that are expelled when a person talks, coughs or sneezes, and because they’ll become covered in those droplets, they should be regularly cleaned...
The effectiveness against small aerosols -- that hang in the air for minutes to hours and that could diffuse around the barrier if it isn’t large -- is simply unclear.
In many ways it’s a similar circumstance to the question over the effectiveness of face shields. Recent analysis has shown while they do block large droplets -- aerosols can travel around them.