With the National Basketball Association (NBA) as an unconventional funding source, Yale researchers have created a COVID-19 test that may give the world its first reprieve during the 2020 pandemic.
Over the weekend—one month after Yale researchers Nathan Grubaugh and Anne Wyllie submitted their test to the FDA—the health agency granted SalivaDirect an Emergency Use Authorization (EUA). SalivaDirect is a saliva-based laboratory diagnostic test that can determine if a patent is infected with the COVID-19 virus. The test rectifies the six core problems Grubaugh and Wyllie saw when looking at current test methods: accessibility, price, ease-of-collection, speed, flexibility and scalability.
Accessibility and price
The critical component of SalivaDirect is that the test uses saliva instead of respiratory swabs, which enables non-invasive frequent sampling and reduces the need for trained healthcare professionals during collection.
In fact, one of the initial research goals of the team was to eliminate the expensive saliva collection tubes that other companies use to preserve the virus for detection. In a separate study led by Wyllie, she and her team found SARS-CoV-2 is stable in saliva for prolonged periods at warm temperatures, so the use of preservatives or specialized tubes are not necessary for the collection of saliva.
“We simplified the test so that it only costs a couple of dollars for reagents, and we expect that labs will only charge about $10 per sample. If cheap alternatives like SalivaDirect can be implemented across the country, we may finally get a handle on this pandemic, even before a vaccine,” said Grubaugh.
A saliva test developed at Rutgers University received EUA approval in mid-April, but it is more expensive. In most cases, it costs about $150 and returns results in 24 to 48 hours. Whereas, SalivaDirect costs about $10 and can return results in just a few hours, definitely within one day.
Ease-of-collection and speed
While half of that simplification stems from no tubes, preservatives or respiratory swabs, the other half is a result of how the researchers designed their diagnostic test. According to the paper, which is available as a preprint on medRxiv, the scientists further simplified the test by “replacing nucleic acid extraction with a simple proteinase K and heat treatment step, and testing specimens with a dualplex quantitative reverse transcription PCR (RT-qPCR) assay.”
Chen Liu, the chair of Yale Pathology, who oversaw clinical validation of the study, said SalivaDirect can double the testing capacity of his laboratory. With an expected second surge of the virus as we head into Autumn, some experts have said up to 4 million tests could be needed per day. SalivaDirect may be one way to manage that number.
Flexibility and scalability
Liu will start offering SalivaDirect as a testing option in his certified clinical laboratory in the coming days, as allowed by the FDA’s EUA, which makes the testing method available to any diagnostic laboratory that wants it. This enables the test to be scaled up quickly in the coming weeks.
A critical component of SalivaDirect is its ability to be used with reagents and instruments from multiple vendors, minimizing the risk of supply chain shortages seen in the early days of the pandemic.
“Regardless of our tested combination of reagents and instruments from different vendors, we found that SalivaDirect is highly sensitive with a limit of detection of 6-12 SARS-CoV-2 copies/μL,” the researchers write in their paper.
The team found at least 94% agreement of SalivaDirect with the authorized Thermo Fisher Scientific TaqPath COVID-19 combo kit. But SalivaDirect is more flexible and cheaper, in addition to be quicker and simpler to collect and test.
“This is a huge step forward to make testing more accessible,” said Chantal Vogels, a Yale postdoctoral fellow, who led the laboratory development and validation along with Doug Brackney, an adjunct assistant clinical professor. “This started off as an idea in our lab soon after we found saliva to be a promising sample type of the detection of SARS-CoV-2, and now it has the potential to be used on a large scale to help protect public health.”
Grubaugh and Wyllie told Yale University they are not seeking to commercialize the method, rather, they want the method to help those most in need.
While NBA players are not the ones in need, and Grubaugh made it clear they didn't design the test for athletes, SalivaDirect was administered to a group of NBA players and staff before the league returned to play. Grubaugh was hesitant of the unconventional partnership at first, but he had willing participants, a deep funding source, and a worldwide need to develop an easy, cheap, accurate test—and he and his team succeeded. Now, SalivaDirect will be further validated as a test for asymptomatic individuals through Yale’s continued partnership with the NBA.