Under a new warning by the Centers for Disease Control and Prevention, face shields, a popular plastic face covering used to protect against COVID-19, are not recommended.
Although the shields seemingly offer protection to the nose and mouth, the large gaps alongside and below the face allow respiratory droplets to escape from the mask, endangering anyone around. However, face shields are effective against coronavirus when used in conjunction with a CDC-recommended mask.
In cold-weathered months, the other coverings on the list are cold weather gear that should not be used as protection against the virus.
Since scarves are made for warmth, the knit fabrics they are made of are not protective against the virus. The CDC warns against any mask made of fabrics that let light pass through as these do not offer adequate protection.
Also on the list are ski masks usually made from polyester, which is poorly ventilated. According to the CDC, the best cloth face masks are those made from a breathable, washable, tightly woven fabric, such as cotton. For the best protection, face masks should have at least two layers of fabric.
Balaclavas are the fourth face covering that is not recommended to protect against the virus. Generally, these do not cover the nose, and even if pulled up to cover the nose, the material and fit of balaclavas would not offer protection against COVID-19.
Any of these face coverings can be worn over a face mask that snuggly covers the nose and mouth, but should not be worn alone as protection against the coronavirus.