Colorado State University plans to test up to 3,000 a day for COVID-19 through saliva test

A new saliva test for the coronavirus that causes COVID-19 has shown promising results and could help Colorado State University increase its testing capacity to 3,000 or more a day, a researcher leading the project said Tuesday.

The SalivaDirect test that associate professor Mark Zabel and his team began screening students, faculty and staff with late last week is significantly cheaper than the tests CSU is currently using from an outside vendor, uses supplies that are more readily available and can be collected and processed entirely on campus, providing results in 8-24 hours, Zabel said.

Because the saliva-based test has not yet received approval from the Food and Drug Administration, CSU is using it alongside the Biodesix nasal-swab tests to compare results. Once it produces 30 positive tests that are also identified by the Biodesix tests, Zabel, an associate professor of microbiology and director of CSU’s Prion Research Center, and his team will publish their findings in a research paper and submit it to the FDA in an effort to receive emergency authorization for its stand-alone use.

CSU has collected about 1,000 saliva samples to be tested since Friday, Zabel said, and five of those produced positive results. The follow-up Biodesix results from the five people those samples came from were not yet available Tuesday for comparison, he said.

“We’re going through the validation stage right now,” Zabel said. “We need to collect enough positive and negative tests to compare it to the FDA-approved tests, and once we do that, we can send it to the FDA for emergency authorization approval.”

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How the test works

Both tests use the polymerase chain reaction (PCR) technique that epidemiologists consider the “gold standard” of testing for the SARS-CoV-2 virus that causes COVID-19, Zabel said.

The biggest differences are in the equipment and reagents needed to perform and analyze the tests. The solutions the nasal swabs must be stored in, reagents required for chemical analysis and even the swabs themselves have been in short supply because of worldwide efforts to ramp up testing, he said.

The SalivaDirect test “is a very low-tech thing,” Zabel said, with saliva stored and analyzed in basic glass tubes that most laboratories have readily available.

“There’s not a lot of processing of the saliva,” he said. “It’s essentially moving it into a new tube, treating it for a few minutes with another agent and then running the assay.”

CSU has its own thermal cycler in a pathology lab on campus to test the samples, eliminating the bottleneck created when couriers have to collect the Biodesix tests and take them to an off-campus lab for testing alongside samples the company is collecting from dozens of other clients each day.

Saliva tests cost about one-tenth of what a nasal-swab test costs, he said. The saliva tests are also less invasive, so people are more likely to get them.

CSU is running about 1,000 saliva tests a day, Zabel said, and plans to quickly ramp that up to 3,000 a day. For comparison’s sake, the combined testing capabilities in Larimer County of UCHealth, Banner, Kaiser, Salud Family Medicine and the county’s community testing sites max out at about 1,500 tests per day, county public health director Tom Gonzales said last week during a virtual town hall meeting that also included officials from the city of Fort Collins and CSU.

The SalivaDirect test was developed by Yale professor Nathan Grubaugh, who earned his Ph.D. in microbiology at CSU in 2016.

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Zabel had been talking to microbiology professor Carol Wilusz about the wastewater testing program she and associate engineering professor Susan DeLong are running and its ability to detect COVID-19 outbreaks days before those infected experience any symptoms when he got the idea to try the saliva-based tests at CSU.

Wastewater samples are being taken at 17 locations across campus, CSU Provost and Executive Vice President Mary Pedersen said in the virtual town hall. Students living in residence halls, along with faculty and staff working in areas where high levels of COVID-19 are found, can then be tested right away, with those testing positive isolated and quarantined to limit the virus’ spread.

“If you pair this with something that detects the virus even earlier, like a wastewater test, you can identify people who are infected before they’re shedding the virus and quarantine those folks even sooner,” Zabel said. “And if they’re quarantined, they never contact anyone before they shed the virus, and that’s the key to stopping the spread.”

CSU recently quarantined 900 students living in two residence halls — Braiden and Summit — for five days while it tested each of them before identifying and isolating nine residents who had COVID-19, a school spokesperson said.

That type of “aggressive” approach has prevented CSU from having the kind of large outbreaks on campus this fall that have occurred at the University of Colorado and others across the country, including Michigan State, North Carolina and Notre Dame, Pedersen said during last week’s town hall.

CSU had reported 305 cases of COVID-19 among its nearly 40,000 students, faculty and staff members since Aug. 17, when students started moving into residence halls for the fall semester.

The university conducted more than 20,105 tests on campus from Aug. 17 through Oct. 1, with 197 testing positive for COVID-19, CSU reported on its COVID-19 dashboard. Those included mandatory tests from Sept. 23 through Oct. 1 for students living in 13 residence halls where wastewater results indicated possible outbreaks and six off-campus fraternity and sorority houses with known outbreaks.

CSU President Joyce McConnell told the Larimer County commissioners Tuesday that the university could test every student, faculty and staff member on campus every other week with the SalivaDirect test for far less money than it is now spending on its targeted testing program.

She said about half of the students who have tested positive have shown no symptoms, and most of the rest have only experienced mild symptoms. About 2% have had more severe symptoms, McConnell said, although none have required hospitalization.

Coloradoan reporter and senior columnist Kevin Duggan contributed to this report.

Kelly Lyell is a Coloradoan reporter. Contact him at kellylyell@coloradoan.com, follow him on Twitter @KellyLyell and find him on Facebook at www.facebook.com/KellyLyell.news. Help support Coloradoan journalists by purchasing a subscription today.