Plastic face shields have advantages over conventional medical masks to protect against coronavirus infection. This is stated in a study by a group of Iowa scientists published in the Journal of American Medical Association (JAMA).
According to the experts, the available data show that the spread of SARS-CoV-2 is typical for respiratory viruses. Among other things, it can be infected by airborne droplets, i.e. through infectious particles that are close enough to the eyes, nose or mouth. Scientists have compared two means of protection that block such transmission: medical masks and plastic face shields.
Studies showed that shields are quite effective at containing the virus. At the recommended distance of six feet from another person (almost two meters), facial shields have captured up to 92% of viral particles, the scientists say.
Unlike masks that have short lifetimes and cannot be reused, plastic protection can be washed with soap and water or conventional household disinfectants and used repeatedly. Specialists who participated in the research also stated that such shields are more comfortable to wear, easier to communicate with others through them, and they do not allow accidental touching of your face by hands (which is one of the ways of virus transmission).
The scientists indicated that the use of this tool is also likely to help curb the spread of the virus and estimated its effectiveness at 68 to 96%. Experts added that plastic shields can be produced at an affordable price and distributed quickly.
At the same time, the researchers specified that the effectiveness of shields, when they are worn by an already sick person, has not been studied.
Earlier, U.S. physicists evaluated the use of homemade face masks and came to the conclusion that masks from two layers of fabric of different types, such as cotton and silk, detain from 80 to 99% of aerosol particles. According to their findings, they are almost as effective as the N95 class respirators recommended for medical personnel in the USA. The scientists specified that the products should fit tightly to the face, as gaps can reduce the effectiveness of masks up to 50%.