WASHINGTON — As the United State grapples with coronavirus surges, scientists at the Food and Drug Administration on Thursday presented an array of mask types that scientists have found to be effective.

“From March of this year, we embarked on updating that model by considering fabrics and their performance, face coverings and their fit and then risk reduction from compliance of such coverings in reducing transmission of COVID-19,” said Suvajyoti Guha, a scientist with the FDA.

According to the Centers for Disease Control and Prevention, the U.S. reported more than 100,000 cases per day in the last three days and averaged over 1,000 deaths daily in the past week.

Guha said how particles can be spread through the air by sneezing, coughing or nasal drip and assessed fabric types to determine which is best at protecting an individual from these sources.

He concluded that most fabrics are good at protecting people from the droplets, but advised that a 1,000-count pillowcase would “not only act as good source control, but may also offer at least some degree of protection against sub-micron aerosols.”

Another FDA scientist, Matthew Myers, using data from New York City and the Princess Diamond Cruise Ship cases in spring, ran experiments to determine the effectiveness of certain protection measures. He concluded that the stronger the mask’s material, the higher the filtration efficiency becomes.

“The calculations show that the do-it-yourself masks can indeed help to flatten the curve,” he said.
Prasanna Hariharan said a 3-D printed face mask designed to be disinfected and reused while replacing the filter on the inside of the mask had potential because it can be made in bulk easily, but warned that more testing on its effectiveness is needed.

Through a partnership with the Navy, Hariharan said that the FDA tested the 3-D masks in several ways, including testing distance between the face and the mask, leakage in design and geometric design. He concluded that more tests are needed to draw a conclusion.

Myers also noted that said checking the efficacy of mask designs is not enough.

“In order to formulate public policy, what we really like to know is how the barriers in mask designs affect the infection rate for a given population,” he said.