Women wearing different types of face masks in downtown San Diego. Courtesy San Diego County HHSA

As California sees a spike in COVID-19 cases, wearing a face covering is now a requirement in most public settings. However, there is still some confusion over when masks are required and which materials provide the best protection.

We know that COVID-19 is primarily transmitted from person to person through respiratory droplets that are produced when an infected person coughs, sneezes, talks, laughs, shouts or sings. They can land in the mouths or noses of people who are nearby or can possibly be inhaled into the lungs. Face coverings, when worn correctly, may reduce the release of infectious particles, thus reducing the spread of COVID-19.

When to Wear a Face Covering

State and local health orders require that people over two years of age wear a face covering when outside their home and unable to maintain a distance of at least six feet from others.

This includes the following situations:

  • Waiting in line to go inside a store
  • Shopping in a store
  • Picking up food at a restaurant
  • In common areas, such as hallways, stairways, elevators and parking facilities
  • Waiting for or riding on public transportation
  • Riding in a taxi or other ride-service vehicle
  • Seeking health care
  • Going into facilities allowed to stay open
  • Working an essential job that interacts with the public
  • Outdoors when unable to maintain six feet from people not from the same household

You are not required to wear a face covering when you are at home, although a face covering is recommended if someone in your home is sick or has been exposed to COVID-19.

There is also no need for face coverings when you are in the car, swimming, walking, hiking, bicycling or running by yourself or with your own household members. However, you should have a face covering readily available in case you come within six feet of others not from your household, such as on a narrow walking trail or when going through a restaurant’s drive-thru.

Types of Face Coverings That Work

Cloth face coverings must cover the nose and mouth and can be snugly secured to the head with ties or straps, or simply wrapped around the lower face. They can be made of cotton, silk or linen and should have at least two layers of densely woven fabric. A cloth face covering can be hand-sewn or factory-made, or can be designed from household items, such as bandanas, scarfs, T-shirts, sweatshirts or towels.

A recent study found that masks made of two-layered quilting cotton blocked the most respiratory droplets from spreading when compared to other types of masks worn by the general public, including a bandana, loosely folded cotton handkerchief and cone-shaped disposable mask. Whatever the material used, it is important to wash your cloth face covering with detergent and hot water after each use or, at the very least, every day.

Disposable surgical, procedural or cone-style face masks provide protection against large respiratory droplets, but are most effective at protecting the person wearing one from transmitting infection to others. However, these types of masks should be reserved for health care workers and other first responders to ensure adequate supplies are available.

Face shields, which are full-face coverings made of clear plastic attached to a headband and extending past the chin with a cloth drape at the bottom, can be considered for those who cannot wear another type of face covering.

Health care providers who work with infected patients often use face shields paired with N95 masks to protect their eyes from respiratory droplets, and some California counties are requiring restaurant workers to wear both face shields and cloth masks. However, for the average person following other precautions, such as social distancing and hand-washing, cloth face masks are currently public health officials’ top choice.

Studies show that a significant number of individuals with COVID-19 can be asymptomatic or pre-symptomatic and still transmit the virus to others. When combined with social distancing and regular hand-washing, wearing face coverings can reduce the spread of COVID-19, which is incredibly important if we hope to decrease the number of illnesses and deaths caused by the disease, and safely reopen schools, businesses and more.

Dr. Stephen Munday, MD, is medical director for occupational medicine at Sharp Rees-Stealy Medical Group.

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