The interim health authority for Austin-Travis County says he expects a recommendation for Austinites to wear fabric face coverings when they're outside the home to become a requirement.

Dr. Mark Escott said Monday the goal of people covering their faces when they're out for essential reasons would be to get people back to work and businesses open sooner by stopping the spread of the coronavirus.

He said masks must be used along with social distancing, not as a substitute. Evidence from the 1918 flu pandemic — believed to have infected one-third of the world's population — suggests cloth masks gave a false sense of security and people continued to interact with one another, he said.

Cotton is preferred for fabric face coverings, Escott said.

"The higher the thread count, the better the filtration is going to be," he said.

"The key points are it needs to cover the mouth and the nose, and it needs to be comfortable for the wearer," Escott said. "What we don't want to happen is for people to wear things which are not comfortable, and they end up adjusting it — touching their face more often than they normally would, because that will defeat the purpose."

He said the guidance may be in place for an extended period of time, so people should have more than one ready to use.

What's behind the new guidance on wearing face coverings? Escott said the point of everyone covering their faces is not to protect the wearer from people who are sick; it's designed to protect other members of the public from the wearer.

"We have increasing evidence that those without symptoms, as well as those who have very mild symptoms that may not even realize they could be infected, have the ability to transmit the disease," Escott said.

People do not need to run out and get surgical masks or N95 masks, he said. If people do have them at home, they can donate them to the Austin Disaster Relief Network to be used by first responders and health care workers "who desperately need those to stay safe."

The city's health officials first recommended on Sunday that people cover their faces while outside the home, following new guidance from the Centers for Disease Control and Prevention.

Making a fabric face covering at home

Here's a step-by-step guide from the CDC's website on how to make a fabric face covering using a T-shirt and two rubber bands. And here's Mayor Steve Adler demonstrating in a video released Sunday: