Study Finds Plastic Face Shields Ineffective Against Coronavirus

As many businesses across the world have opened back up, workers dealing with the public are commonly wearing face shields to protect themselves and those around them from contracting COVID-19. However, a simulation conducted by Riken, a government-based Japanese research center in Kobe, showed they are ineffective at trapping airborne droplets, The Guardian reports.

Riken tested the plastic face shields using Fugaku, dubbed the world’s fastest supercomputer, which found that close to 100% of airborne droplets less than five micrometers in size escaped through the shields. Makoto Tsubokura, Riken’s team leader at the center for computational science, said the Fugaku simulation combined air flow with tens of thousands of droplets of various sizes ranging from one micrometer to several hundred micrometers.

About half of the larger droplets measuring 50 micrometers made their way into the air, according to Riken. Tsubokura said the simulation results showed the limitation that face shields have against coronavirus compared with regular face masks. He recommended that people wear face masks instead. Face shields should only be worn outdoors or in facilities with proper ventilation, he added.

Other Fugaku simulations found that face masks made from nonwoven fabric are more effective against the spread of coronavirus than cotton and polyester. Experts are hoping next year Fugaku can help identify treatments for COVID-19 from about 2,000 existing drugs.