What does the latest research tell us about face shields vs face masks?
Face shields seem to be gaining popularity of late, with many people opting to wear them instead of face masks.
Even members of the royal family have jumped on the bandwagon, with Camilla, Duchess of Cornwall recently donning a face shield during a royal engagement to the Medical Detection Dogs training centre in Buckinghamshire.
While the Duchess reportedly chose the face shield because it was “easier to communicate”, many people have criticised the Duchess for wearing the visor too high, exposing her mouth.
With face shields now added to the mix of PPE, we wanted to know, are they a safe and effective alternative to face masks?
Face shields vs face masks
The US Centre for Disease Control does not recommend the use of face shield as a substitute for face masks.
Face shields can reduce the risk of contracting viruses, however are much less effective at limiting the spread of droplets from the wearer, explains Dr Michael B Edmond from the University of Iowa Health Care.
“The primary mechanism of transmission of COVID appears to be via droplets,” he told Healthline.
“Face shields are excellent at preventing droplets from coming into contact with the nose, mouth, and eyes, which are the body sites that the virus enters to establish infection.”
Moreover, studies have shown that face shields provide minimal protection against the spread of COVID-19.
Research published in Physics of Fluids demonstrating the effectiveness of face shields found that while they initially blocked the forward motion of droplets, they still moved underneath and around the visor.
The video below shows how droplets spread underneath and around plastic face shields, spreading out over a large area.
These findings were backed up by a study out of Switzerland, which found that following a COVID-19 outbreak, several people wearing only face shields tested positive for the virus, while none of the people wearing face masks contracted it.
When should you wear face shields?
Dr Joy Henningsen, a clinical assistant professor at the University of Alabama says that while face shields work well in addition to face masks, they should not be used in their place.
“There’s no such thing as too many weapons against the novel coronavirus,” said Henningsen. “The more protection, the better.”
“Face coverings, regular hand washing, physical distancing, and staying home as much as possible are very good tools. Add a face shield to all of those requisite practices and you go from ‘good’ to ‘great,’” she said.
The bottom line: only use face shields in addition, not a replacement to face masks.
