A Japanese supercomputer found the shields to be almost entirely ineffective
Plastic face shields are significantly less effective at preventing the spread of Covid-19 than face masks, and provide almost no protection from airborne droplets.
According to experiments and simulations carried out by Fugaku, the world’s fastest supercomputer, almost 100 percent of all airborne droplets smaller than 5 micrometres (one millionth of a metre) made their way into the air when using a face shield.
Makoto Tsubokura of Riken, the government-backed institution carrying out the research, told the Guardian that the results, though carried out in a simulation, suggests that people should not opt to wear plastic shields as an alternative to a face mask.
“Judging from the results of the simulation, unfortunately the effectiveness of face guards in preventing droplets from spreading from an infected person’s mouth is limited compared with masks.
“This is especially true for small droplets of less than 20 micrometres. At the same time, it somehow works for the droplets larger than 50 micrometres.”
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Though governments around the world have implemented a number of guidelines advising or enforcing the wearing of face masks in certain public areas, face shields have often been worn by staff working in the retail or hospitality industry.
On Tuesday of this week, Boris Johnson announced tighter coronavirus restrictions to try and halt the recent surge in cases. As part of these new measures, people found to not be wearing face masks in required public locations could face fines of up to £200.