Yale News

SalivaDirect, a Yale-created protocol that allows for greater efficiency in COVID-19 testing, has received FDA emergency use authorization to be used for pooled COVID-19 virus testing of up to five individual samples at a time. 

SalivaDirect is a PCR test which uses self-collected saliva to detect COVID-19 cases. It was developed by a team of researchers at the Yale School of Public Health. The team began its research in March 2020. In August 2020, SalivaDirect received its initial EUA from the Food and Drug Administration.

“Testing is still critically important for getting us out of the pandemic,” Nathan Grubaugh, associate professor of epidemiology at the School of Public Health, wrote in an email. “The goal of SalivaDirect is to be as flexible as possible to provide testing options for a multitude of uses. Pooling up to five samples prior to testing will be a great option for screening programs where the population has an expected low positivity rate, such as for routine school or university testing. This helps to preserve resources and drive down the costs.”

Anne Wyllie, research scientist at the School of Public Health, leads the SalivaDirect team. At the onset of the COVID-19 pandemic, she noticed that there were a lot of challenges involved with nasopharyngeal swabs, which were the “gold standard” of COVID-19 testing. Wyllie explained that the supply chains for swabs were collapsing, since the swabs were coming from Italy — a country that experienced a very early outbreak. In addition, mostly those who could afford a COVID-19 test were able to get tested. Moreover, Wyllie noted that getting tested with the swabs was “not exactly pleasant” since the procedure required those who administered the test to “jab” the swab into the nostril of the person being tested.

Having worked with saliva as a sample type for the past 10 years in her research, Wyllie wondered if a testing method using saliva could be developed, since “saliva is much easier to collect.” Although she was “definitely one of the most junior on the team” at the time, after explaining her idea to others, she received support from researchers at Yale.

“First of all, we set out to develop SalivaDirect to increase access,” Wyllie said. “Early on in the pandemic we were really frustrated that … other than symptomatic people, … people who could afford to get tested were the only other ones who could get tested … We were determined to develop a test that could be more affordable … We also wanted to make a kit that could be used by others. We wanted to make [it] a very open source protocol that other labs could readily pick up, start using and decrease the time it would take them to implement an EUA test in their community.”

Annie Watkins SPH ’21, former graduate research assistant at the School of Public Health, emphasized that a main focus of the research team was to ensure that “testing could be more readily available” by “cut[ting] out some of the barriers.”

Watkins observed that the team managed to “work quite hard” to validate the SalivaDirect protocol across multiple different testing platforms and reagents. She noted that these validations would prevent labs from needing to rely on one machine or supply kit, allowing them to take advantage of the supplies they have or can easily acquire. As a result, the labs would be able to “keep costs down but quality up.”

Pooling samples together creates significant advantages in terms of streamlining COVID-19 tests and their costs.

“One of the unique aspects of SalivaDirect is that it is a simplified and flexible platform that is being further developed by the SalivaDirect team,” Chantal Vogels, associate research scientist at the School of Public Health, wrote in an email to the News. “[The] pooling of samples … will help to further reduce cost and increase testing capacity.”

According to Wyllie, being able to pool up to five samples is a reasonable amount, since pooling together at most five individual samples does not burden labs who can conduct only manual tests “all by hand.” She explained that if the pooled sample produces a positive result, then the lab needs to go back and retest all the individual samples.  

Despite the FDA approval for pooled testing, Wyllie does not anticipate Yale switching its current method of conducting COVID-19 tests through nasal swabs to SalivaDirect. She recalled that when Yale decided to bring students back to campus in fall 2020, the University had considered using SalivaDirect as the method of COVID-19 testing. However, they needed to have an EUA test available for the students, and back then, SalivaDirect had not received its first EUA from the FDA yet. To avoid the risk of setting up an entire testing program that might not have an EUA, Yale decided to provide their students with anterior nasal swab tests.

“I can very much understand how much work goes into setting up testing programs,” said Wyllie. “It’s also the costs that are involved with completely changing the system over again as well.”

Wyllie emphasized the importance for labs and research groups to continue their work even when the number of COVID-19 cases start decreasing. 

According to Wyllie, when case rates start decreasing and fewer COVID-19 tests are being administered, surges around the country occur “again and again.” This trend was demonstrated around spring time in 2021, when labs stopped conducting surveillance testing because of a decline in cases, and another COVID-19 surge occurred shortly after. It is important that labs continue to stay in operation in order to account for any possible future case spikes, she said.

Wyllie and her research team plan to continue SalivaDirect research. Wyllie noted that other labs sometimes approach her team and ask them to experiment with and include a specific instrument in the EUA, which will then allow that lab to use SalivaDirect with materials they have access to.

According to the Center for Disease Control and Prevention COVID-19 data tracker, as of Nov. 8, there are 598 COVID-19 cases in New Haven.