Can a face shield replace a mask? Research has something to say

By Rahul Vaimal, Associate Editor
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Face shield - Face mask
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We have all seen people wearing face masks as well as face shields. Have you ever thought of swapping your tight-fitting mask for a relatively comfortable plastic shield? If your answer is yes, then stop! Studies have shown that face shields are not a good alternative.

According to research conducted under Japanese government support with the world’s fastest computer Fugaku, the airborne particles of less than five micrometers escaped completely through the gap between the face and a face shield. Further, the research found that nearly half of the larger droplets measuring up to 50 micrometers, also floated into the air through the gap, only the larger particles were trapped in the shield.

Another study published in the journal Physics of Fluids suggests that even though face shields can initially hinder the path of droplets from a simulated cough, the fine particles will easily float through the gaps in the side and easily spread to a larger area.

The experiment visualized the travel patterns of the respiratory particles by stimulating coughing and sneezing for which the researchers fixed a hollow manikin head with a manual pump and then expelled vapor through its mouth, laser sheets were used to trace the path of the droplet.

In 2014 a study on ‘Efficacy of face shield against cough aerosol droplets from a cough simulator’ which was published in the Journal of Occupational and Environmental Hygiene, concluded that face shields can reduce the short-term exposure of healthcare workers to ‘large infectious aerosol particles’ but the tiny particles can float around the face shield for a longer time. 

“Face shields provide a useful adjunct to respiratory protection for workers caring for patients with respiratory infections. However, they cannot be used as a substitute for respiratory protection when it is needed,” the study observed.

The internal medicine expert at Apollo Spectra Hospital in India, Dr. Tushar Rane, says that the face shields can give fair protection in a public space whereas its capability to guard in a crowded or healthcare space is highly limited. While a well-fitted N95 or a three-ply surgical face mask can assure sufficient protection. 

Dr. Rane further added that “In a healthcare facility, it is always preferable to use a face mask and a face shield for better protection from exposure to the virus.”  

People have started to switch to face shields not only because it is highly comfortable but it also enables them to see one’s face. Experts suggest that it is better to wear both, as a face shield can give extra protection with face masks.