Studies published in journals like Physics of Fluids highlight several critical reasons why face shields fail as standalone protection:
While shields block the initial forward "jet" of a cough or sneeze, smaller aerosolized droplets can easily flow around the sides and bottom of the visor. Study: Face Shields Not a Good Mask Substitute
Research on the efficacy of face shields confirms that while they are excellent for blocking large splashes, they are in preventing the spread of airborne pathogens like COVID-19. Studies published in journals like Physics of Fluids
The Centers for Disease Control and Prevention (CDC) and other health authorities do not recommend face shields as a primary substitute for cloth face coverings because they lack a peripheral seal. Study: Face Shields Not a Good Mask Substitute