SAN ANTONIO – Experts say face masks are the best weapon against the spread of COVID-19. Some of you at home say, show me the proof. So the Trouble Shooters teamed up with scientists for an experiment with eye-opening results.
We worked with medical laboratory scientists at UT Health San Antonio’s School of Health Professions. They’re the people who run the tests doctors use to diagnose you, including COVID-19 tests.
We begin with petri dishes spaced out at two feet, four feet and six feet. Terri Murphy-Sanchez is the microbiologist in charge. She’s an assistant professor and interim chair of the school’s medical laboratory sciences division.
"So she's going to cough for 15 seconds,” Murphy-Sanchez explains.
Cordy Kudika is our test subject. She’s an assistant professor and director of clinical education in the school’s Division of Medical Laboratory Sciences.
Kudika coughs, talks, sneezes and even sings without a mask. We watch as invisible particles from her mouth travel through the air.
Then, she puts on a face mask.
"I brought my cloth mask in order to conduct this experiment because that's what most people are wearing,” Kudika explains as she puts on a gray cotton mask.
She once again coughs, talks, sneezes and sings to see if particles get through that cloth mask.
Next, the petri dishes spend 24 hours in an incubator.
"They're allowing the bacteria an opportunity to grow, so they're cooking at the same temperature as your body temperature,” Murphy-Sanchez explains.
First, we look at the red, close contact dishes.
"When you have a normal conversation, it's closer - two feet or less, typically,” Murphy-Sanchez says. “The plate that was the most shocking was the sneeze without a mask."
The sneeze without a mask shows bacteria covering one-quarter of the dish with more bacteria spread across the surface. The sneeze with a mask shows no bacteria on the petri dish.
"The talking one is shocking as well,” Murphy-Sanchez says.
Talking one minute without a mask also spread bacteria across the entire dish, with a cluster on one side. Talking one minute with a mask, though, left no bacteria.
It’s the same story with singing as well as coughing, a COVID-19 symptom.
"I know I've seen someone at Costco cough continuously for almost a minute, and they've pulled their mask down to do so. And I'm like that, defeats the purpose,” Murphy-Sanchez says.
Next, we examined the brown petri dishes that tested distance. At two feet, you see bacteria. At four feet, it’s diminishing. And at six feet, there’s no bacteria. That’s why six feet is the recommended social distance.
The bottom line for these lab scientists: wearing a mask works. They tell us non-surgical medical masks are getting easier to find in stores and work just as well as the masks they wear in the lab - and so does a two-layer cloth mask.
Whatever you choose, they say don’t get complacent: wear face masks, even around family members who live in different households.
"Don't let your guard down,” Murphy-Sanchez says. “It's really important to be aware either until we have a vaccine or we can get the virus under control."
By EMILY BAUCUM