Scratch-And-Sniff Test May Prove Huge Help In COVID Fight, Some Experts Say

Researchers at the University of Colorado are giving new meaning to the question, "Does it pass the smell test?" Believe it or not, a scratch-and-sniff test may be the best hope, after an effective vaccine, to control the spread of COVID-19, they say.

CU Biochemistry Professor Roy Parker admits he was skeptical of the test at first. Yale University colleague and former CU undergrad Derek Toomre developed it and asked Parker and CU computer scientist Dan Larremore to study its effectiveness.

"I think the amazing thing is it worked better than I think we thought it would," Parker told CBS Denver.

Someone scratches a card resembling a lottery rub-off card, sniffs, then enters on a cellphone app what scent he or she has just detected – if any.

He and Larremore developed mathematical models of different venues, including a college campus, and studied how effective the smell test would be at curbing infection. They found that using it every three days would identify more infections than using the gold standard PCR test once a week.

"Your ability to smell is lost in 80% of people with COVID," Parker points out. But just 25% of people with the coronavirus run a fever and it only lasts a day or two, while people lose their sense of smell for a week or longer.

Many of them, Parker says, don't notice it, but the test does. He explains that if the scratch-and-smell test finds someone has an impaired sense of smell, it tells the person who just took it to "go get a real test," as Parker put it.

The scratch-and-sniff test is a screening tool but, Parker says, at a cost of 50 cents per card versus $20 per COVID-19 test, it could go a long way toward reducing the spread of the virus, especially in large venues like football stadiums, concert halls and airports.

"If we can catch 80% of the people who have COVID but don't know it, it could make a huge impact," Parker says. "We're all looking for solutions right now. We're in a pandemic and we can't wait for the perfect solution. This is something we can try right now, it should work and we should be trying it."

Parker plans to try the test in a real-life setting like a dorm. Toomre's company, U-Smell-It, has asked for emergency approval from the FDA and, he says, once it has that it can begin producing hundreds of millions of tests a week.