Saliva testing for COVID-19 may be as good as a nasal swab: study

A new study is shedding light on the effectiveness of saliva testing for the diagnosis of COVID-19. (Photo; Getty Creative Stock Photo)

Nasopharyngeal swabs have been considered the gold standard in COVID-19 testing, but there is a new, more comfortable option that can be just as effective.

New research published in New England Journal of Medicine A saliva test developed at Yale University was found to be at least as effective as a nasal swab in detecting SARS-CoV-2, which causes the virus COVID-19. The test, called salivadirect, has been used by the NBA to test players and staff this season. The Food and Drug Administration (FDA) indirectly issued an emergency use authority for saliva in mid-August.

For the study, the researchers tested 70 patients at Yale-New Haven Hospital who had COVID-19 confirmed with a nasopharyngeal swab. One to five days after his diagnosis, 81 percent of saliva samples were positive for the virus, while 71 percent were with nasal swabs.

Six to 10 days after diagnosis, 76 percent of salivary tests were positive, while only 65 percent of nasal inflammation was positive. But 41 percent of saliva samples tested positive for the virus on day 11, while 50 percent of the nasal samples were positive.

Researchers also used saliva tests on 495 health care workers with no symptoms of COVID-19. Of them, 13 tested positive for the virus through saliva testing. Nine of those 13 also tested nasopharyngeal swab, and seven of them tested positive. The original 13 positives were eventually later confirmed with nasal swabs. The authors of the study wrote, “Given the increasing need for testing, our findings provide support for the ability of saliva samples in the diagnosis of SARS-COV-2 infection.”

While the use of saliva tests to detect COVID-19 is not new, this particular test has one less step in processing that may make it more efficient than other tests, Drs. Amesh A. Adalja, senior scholar health safety at the Johns Hopkins Center, tells Yahoo Life. “The clinical testing process for Yale testing does not require chemicals called reagents,” he explains. “These chemicals are in short supply.”

Although it is not as fast as a rapid test that can be done in a doctor’s office, it is a step towards a simpler testing process, Adiraj says. “It’s growing that way, but it’s not all the way yet,” he says. “It can improve testing and remove some obstacles.”

But Dr. William Scheffner, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, tells Yahoo Life that the test is a “great help” in testing COVID-19. Among other things, he says, it can help people feel more comfortable doing tests. “It’s definitely less of an attack than a nasopharyngeal swab. He may feel like you’re being attacked,” he says.

However, saliva is not indirectly correct. Although the accuracy figures are on par with the nasopharyngeal swab, Scheffner points out that they still missed about 20 percent of positive cases in the NEJM study. He also said that laboratory testing is required for this test, which may slow down the results. “We need labs to process these tests, and this can easily be a chokepoint, as it always has been,” Schehner says. “But the more tests we have, the better.”

“We can’t just test our way with COVID-19, but testing is absolutely fundamental as part of this virus-fighting strategy,” says Scheffner.

While the SalivaDirect trial recently gained its Emergency Use Authority, Adalja hopes that it will “start going out” to medical centers soon.

for Latest Coronavirus news and updates, Follow along According to experts, people over 60 and immunocompromised are at greatest risk. If you have any questions, please reference CDC‘Sand Who is it Resource guide.

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