Saliva Tests Show Promise 🤞

Data suggests spit may be an acceptable alternative to nasopharyngeal swab samples to detect Covid-19

Alexandra Sifferlin
Medium Coronavirus Blog
3 min readAug 31, 2020

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Photo: Suzanne Puttman Photography/Getty Images

I need to disclose some bias. I would much prefer to spit in a tube than have a swab spun around in the back of my nose and throat. To be clear, I’ve happily received multiple nasopharyngeal swabs because it’s important to get tested for Covid-19. While I don’t actually think the nasopharyngeal swab is painful (though others disagree), I do find it uncomfortable, and I’ve been keeping my fingers crossed for more widespread use of tests that rely on saliva.

Now there’s some early research published in the New England Journal of Medicine that offers strong support for using saliva as an alternative to nasopharyngeal swab samples to detect SARS-CoV-2, the virus that causes Covid-19.

The researchers at Yale School of Public Health and the Yale School of Medicine studied 70 people with confirmed Covid-19. The men and women first tested positive for Covid-19 with the standard nasopharyngeal swab, and also agreed to provide saliva samples that they collected themselves. The researchers tested both samples and detected more SARS-CoV-2 RNA copies in the saliva samples than in the nasopharyngeal swab samples. A higher percentage of saliva samples than nasopharyngeal swab samples also tested positive up to 10 days after the Covid-19 diagnosis. The researchers also observed less variation in levels of SARS-CoV-2 RNA in the saliva samples. “These findings suggest that saliva specimens and nasopharyngeal swab specimens have at least similar sensitivity in the detection of SARS-CoV-2 during the course of hospitalization,” the researchers write.

The researchers also looked at the effectiveness of using saliva samples to identify the virus in people without symptoms of Covid-19. They screened nearly 500 asymptomatic health care workers and tested both saliva and nasopharyngeal samples from the men and women. They found SARS-CoV-2 in the saliva samples of 13 people who did not have any…

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Alexandra Sifferlin
Medium Coronavirus Blog

Health and science journalist. Former editor of Medium’s Covid-19 Blog and deputy editor at Elemental. TIME Magazine writer before that