Shocking video shows face shields don't protect against Covid-19

A study has found plastic face shields don’t protect against Covid-19 if an infected person wearing no mask sneezes nearby.

Researchers revealed “vortex rings” produced by the sneeze carry infectious particles to the face shield in less than a second and stick to the edges of the plastic. If the timing of this wave of coronavirus particles coincides with the face shield wearer breathing in, the person can become infected, they said.

A Japanese computer simulation revealed almost all airborne droplets smaller than five micrometres in size released when talking and breathing escaped through the visor and half of larger droplets measuring 50 micrometres in size, given off by coughs and sneezes, found their way into the air, posing a risk to others.

The latest study by researchers at Fukuoka University in Japan and published in the journal Physics of Fluids further is yet another proof against the use of face shields.

A shocking video published alongside the study illustrates how air flow from a sneeze can make its way around and up the inside of a face shield and into a person’s mouth or nose, rendering the PPE useless without a face mask being worn as well.

Researchers looked specifically at sneezes because of the creation of a phenomena known as vortex rings.

“A vortex ring is a donut-shaped vortex that is generated by an instantaneous ejection of fluid from a circular orifice,” said study author Dr Fujio Akagi. “This resembles bubble rings made by dolphins.”

“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.”

“We are currently developing and demonstrating several improved shields,” said Dr Akagi.

“We want to contribute to keeping people safe from infection, and believe that one day in the near future, medical workers will be able to prevent infection using only a face shield and a regular mask or, ideally, with only a face shield.”