Don’t count on face shields to protect you from COVID-19: study
Face shields aren’t really shielding much.
A new study is the latest science casting doubt on plastic face shields in the fight against COVID-19.
The study included a video to illustrate how a sneeze from a person infected with the coronavirus carries “vortex rings” of contagious particles under a face shield, rendering the PPE useless, according to the findings published by Fukuoka University researchers in Japan in the journal Physics of Fluids.
“The vortex rings generated by the sneeze capture the microscopic droplets within the sneeze and transport them to the top and bottom edges of the face shield,” head researcher Dr. Fujio Akagi told the the Daily Mail. In the computer-generated model, a sneeze, with COVID-infected particles along for the ride, travelled a surprising distance, about 3 feet.
Think of the vortex rings like the “bubble rings made by dolphins,” added Akagi, who mapped the trajectory of a sneeze travelling between a sick person and another wearing a shield, found on the foreheads of barbers, waiters, grocery shoppers and travelers alike.
Similar findings from the Swiss government revealed that an outbreak at an Alps hotel showed that those who wore only a face shield, without a mask, were more likely to get sick.
The face shields don’t block germy aerosols, and they don’t keep them in either. The open sides and bottom of the visor allow particles to escape into the air. The Japanese study simulated a sneeze with droplets smaller than 5 micrometers to demonstrate this.
Even though loading on extra layers of protection might feel safer, face shields, hazmat suits and gloves could give a false sense of security.
The best bet for protecting others from infection is masks, according to scientists and public health agencies such as the Centers for Disease Control and Prevention, plus frequent hand washing or sanitizing.