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At the start of the COVID-19 pandemic, nasopharyngeal swabs were the gold standard of testing for virus infection. But as the crisis has worn on, saliva tests have gained popularity.
A growing body of research shows that saliva samples are equally reliable for detecting SARS-CoV-2, the virus that causes COVID-19. And biotech companies and universities are researching and developing saliva tests for their ease of use, including the ability for people to easily and conveniently collect their own samples.
“It is important that we have options,” Anne Wyllie, PhD, associate research scientist in epidemiology at Yale School of Medicine, tells Verywell. “We saw early on the supply-chain issues when solely relying on nasopharyngeal swabs. We now know many people avoid having swabs taken. Additional sample types—such as saliva—help to provide other options.”
Wyllie and her colleagues at Yale conducted some early research in the spring, now published in the New England Journal of Medicine, comparing nasopharyngeal swabs with saliva samples. “We—and others—have seen high concordance between saliva and swabs,” Wyllie says.
The Yale study involved 70 hospitalized patients with COVID-19 confirmed with a nasopharyngeal swab at the time of admittance. The researchers later had the patients collect their own saliva samples. At the same juncture, healthcare workers also collected a nasopharyngeal swab from those same patients.
The researchers detected more copies of SARS-CoV-2 RNA, the genetic material of the virus, in the saliva samples than in the nasopharyngeal specimens. And a higher percentage of saliva samples, when compared to nasopharyngeal samples, tested positive for up to 10 days after diagnosis. For example, between one and five days after the patients were diagnosed with COVID-19, 81% of the saliva samples tested positive for the virus, whereas 71% of the nasopharyngeal sampless did.
Researchers at Memorial Sloan Kettering Cancer Center recently released a study published in The Journal of Molecular Diagnostics that looks at the reliability of self-collected saliva samples. The study, also conducted in the spring, involved 285 Memorial Sloan Kettering employees who either had symptoms consistent with COVID-19 or required testing because of possible exposure to someone with the virus. The participants provided paired self-administered samples. One pair included a saliva specimen and a nasopharyngeal swab. The agreement between the two specimens was 97.7% And the specificity, which is how well a test can determine a true negative, was 94.1%.
To test for sample stability, specimens were stored in a transport cooler at room temperature, and showed no significant difference in virus concentration at time of collection, after eight hours, or after 24 hours.
If you have to take a COVID-19 test but have been dreading a nasopharyngeal swab, a saliva test may be an option for you. Research shows saliva tests are just as reliable at detecting the presence or absence of the virus.
Collecting a saliva specimen isn’t invasive, the samples are reliable, and they keep at room temperature. For all of these reasons, saliva testing options can help overcome some challenges of the pandemic, Wyllie says.
“People can quickly and easily collect their own samples and drop them off for testing,” she explains. “This decreases collection costs and decreases the time required to collect samples.”
Early on in the pandemic, people who needed to get tested for SARS-CoV-2 often had to wait in long lines before getting the dreaded nasopharyngeal swab—that is if they were even able to get tested at all.
“That was the first thing that was available,” Vian Nguyen, MD, national medical director for Wellness 4 Humanity, a company that provides COVID-19 testing kits, tells Verywell. “But in addition to that, it was scarce. There was very limited supply of this type of testing.”
Scarce resources of nasopharyngeal swabs has not been the only driver for a different test type. Patients have also been pushing for a better way. Lian Nguyen Pham, CEO and co-founder of Wellness 4 Humanity, tells Verywell that the company originally used its saliva test in clinical settings. “We saw that everybody actually wanted to request that versus the nasopharyngeal swab,” she says. “It was more popular in the elderly and also kids. It’s just more versatile, and the self-collection is huge.”
As a result of the demand for simpler testing methods and more affordable access, biotech companies and universities have been pursing research and development in the COVID-19 testing space. And that’s why we’re seeing more saliva testing options hitting the market now, and we’ll continue to see rollout in 2021.
The Food and Drug Administration (FDA) shows more than 10 saliva tests with current emergency use authorization (EAU) to date. Some saliva tests can be self-administered at home with samples then shipped to a designated lab for results, while others are intended for use at testing sites or in a healthcare provider’s location.
SUNY Upstate Medical University and Quadrant Biosciences, a startup based on the university’s Syracuse campus, received EAU from the FDA in September for its Clarifi COVID-19 test, which uses a saliva swab. The test has helped boost SUNY’s testing capacity. It is being used for its pooled testing protocols, which allows for testing more than 15,000 samples per day in just one lab.
Stanford Medicine is pursuing a pilot study for an at-home COVID-19 saliva test, invented by Manu Prakash, PhD, associate research professor of bioengineering, and team. The test is intended to detect the presence or absence of the virus within 30 minutes without the need of a lab. And if approved down the road, the test could prove to be a more affordable option at just $5 or under. Right now, many at-home tests cost more than $100 without insurance.
Wellness 4 Humanity just announced its plan to make tests easier to get. In the new year, it will roll out COVID-19 testing kit vending machines in airports, grocery stores, and other locations in select cities. In addition to dispensing rapid antigen tests that provide results within 15 minutes, the vending machines will also dispense reverse-transcriptase polymerase chain reaction (RT-qPCR) saliva tests.
People will be able to self-administer the saliva tests and then ship the sample off to a testing lab with a pre-paid label. Users would then receive their results through an app within 48 hours. The company currently offers both of these tests for order online.
“We want to be able to provide the tools that have been very limited early on in the pandemic,” Nguyen says.
The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
By Jennifer Chesak
Chesak has nearly two decades of experience as a medical journalist, editor, and fact-checker. She is the author of "The Psilocybin Handbook for Women."
