Saliva-Based COVID-19 Testing May Be More Effective at Detecting Omicron Variant

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New research is showing that COVID-19 saliva tests might be more effective at detecting the COVID omicron variant.

The variant is highly contagious and responsible for thousands of Connecticut residents getting sick. Studies have shown that some people are testing negative for COVID-19 with at-home tests even if they have the variant.

Dr. Anne Wyllie from the Yale School of Public Health talked about the new research with NBC Connecticut's Dan Corcoran.

Dan: "We've talked to you before about your work with SalivaDirect, which uses spit samples instead of nasal swabs to detect COVID. With Omicron now the dominant variant, why would saliva-based testing be more effective and reliable than those nasal tests?"

Dr. Wyllie: "What we're seeing with omicron, as it were, potentially a shift in its infection profile. If you're thinking about the early symptoms that you're hearing reported, you know, you're hearing a lot more sore throats, a lot less in the loss of smell. And so it's suggesting to us that the infection's a lot lower in the respiratory tract, then with previous variants."

Dan: "How do these tests actually work? Walk us through the process of collecting and testing that sample."

Dr. Wyllie: "The vast majority of saliva-based tests in the U.S. at the moment are still PCR-based tests. And it's as simple as drooling into a tube."

Dan: "Because the mouth is different environment than the nasal passage, if someone eats or drinks before that test, would that affect the results in any way?"

Dr. Wyllie: "It can do so. Many tests do suggest that you wait for at least half an hour after you've had something to eat, had something to drink, maybe 10 minutes after a glass of water. This is especially important right now, as people are sort of turning to modify the rapid test they have at home and are taking mouth swabs. If you are looking to do that, definitely try and wait to make sure that nothing's going to interfere with your test."

Dan: "Is that an effective way to test for COVID-19 - taking those nasal tests and actually using them in your mouth?"

Dr. Wyllie: "It's not how they were designed. It's not how the FDA has authorized them to be used. It's not what the manufacturers have authorized for use. But you know, a lot of the evidence that we're seeing out there, many people are doing that because their nasal swabs are continuing to test negative for days on end. But as soon as they add an oral swab, it's turning out positive, just as they're suspecting."

Dan: "There are some testing sites in the New Haven area that use saliva test, but the nasal swabs are still way more common. If saliva is possibly the better method, what's preventing those kinds of tests from becoming more widely available?"

Dr. Wyllie: "I think it's just highlighting that we need to be flexible in our response to this virus. You know, now that we've learned that potentially Omicron starts off with a much higher infection in the mouth, meaning they have a lot more infectiousness, contagiousness happening on days before nasal swab-based tests are detecting it, than we need to think about updating our testing approaches. And if Omicron is going to continue to be our most dominant variant across the country, I think many testing programs are going to need to reconsider how they approach testing so that we can provide the best public health response possible."

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