The U.S. Centers for Disease Control and Prevention (CDC) offers a beard and mustache guide graphic that shows what types of facial hair will make medical masks less effective.
It comes as the demand for the masks has skyrocketed in recent days amid the COVID-19 coronavirus outbreak, and as the disease spreads outside of China, leading to shortages and price gouging.
Small mustaches such as the “Zorro,” “Zappa,” walrus, or pencil mustaches are fine, but full beards, goatees, and even some stubble are not recommended for mask usage.
Standard beards and long sideburns are risky because the hair could come into contact with the exhalation valve, reducing their effectiveness, according to the CDC’s graphic.
“For any style, hair should not cross under the respirator sealing surface,” a CDC blog post said. “If your respirator has an exhalation valve, some of these styles may interfere with the valve working properly if the facial hair comes in contact with it.”
On Feb. 12, the agency said it does not recommend that Americans wear a respirator or mask in public outside of workplace settings.
“Most often, spread of respiratory viruses from person-to-person happens among close contacts (within 6 feet). CDC recommends everyday preventive actions to prevent the spread of respiratory viruses, such as avoiding people who are sick, avoiding touching your eyes or nose, and covering your cough or sneeze with a tissue,” the agency wrote.
Health and Human Services Secretary Alex Azar announced Wednesday that 60 confirmed cases of the virus have been found in the United States, with the majority of patients having been evacuated from the Diamond Princess cruise ship, which was held in isolation off the Japanese coast for weeks. Most of the other cases were travelers coming back from China or their spouses, and three others were evacuated from China.