UC Berkeley launches trial of saliva test for COVID-19

Jackie Childers, a graduate student in integrative biology, provides a saliva sample for a trial to assess whether testing for the SARS-CoV-2 virus in saliva is as reliable as testing samples obtained with nasal swabs. Saliva sampling is faster and could enable regular monitoring of asymptomatic staff and students as more people return to campus. (UC Berkeley photo by Irene Yi)

Scientists from the Innovative Genomics Institute (IGI), the same UC Berkeley group that rapidly popped up a state-of-the-art COVID-19 testing laboratory in March, are now trialing a quicker way to obtain patient samples: through saliva.

To date, diagnostic tests for COVID-19 have relied on samples obtained by swabbing uncomfortably deep into a person’s nasal passages or in the mouth and nose, but those tests must be administered by trained medical staff wearing personal protective equipment (PPE).

Saliva, collected in the same way companies like 23andMe and Ancestry.com get samples for DNA genealogy analysis, can be gathered without medical supervision, and that saves time, money and precious PPE.

If the new study demonstrates that detecting the coronavirus in saliva is just as reliable as using nasal swabs, UC Berkeley will be able to ramp up the monitoring of students, faculty and staff as the campus gradually opens in preparation for the start of classes in late August.

Jennifer Doudna talks with Alex Ehrenberg, a graduate student in integrative biology who is helping organize the FAST trial of saliva tests for COVID-19. (UC Berkeley photo by Irene Yi)

"At Berkeley, we hope to bring at least some of our undergraduate students back to campus safely in the fall, and one way to do that is to provide them with asymptomatic regular testing, so that we can be monitoring their health and insuring that they are not transmitting the virus," said Jennifer Doudna, who spearheaded the pop-up diagnostics lab and the saliva testing. Doudna is a UC Berkeley professor of molecular and cell biology and of chemistry, a Howard Hughes Medical Institute investigator and the executive director of the IGI , which is organizing the experimental study.

Infected people can spread the virus before symptoms appear, or even if symptoms never appear. Regular testing would, in theory, allow the campus to catch infected, but asymptomatic, people early, isolate them, trace and quarantine their close contacts and ideally tamp down inevitable flare-ups before they spread.

Campus volunteers began collecting saliva samples from a few hundred UC Berkeley employees on June 23 at kiosks set up in the breezeway of the Genetics and Plant Biology building, near Pat Brown’s Grill.

"As opposed to swab testing, saliva testing is a lot simpler and allows people to literally spit into a tube," Doudna said. "We think it will take about five or six minutes as they pass through our testing center here, so we hope to make this very painless, easy and simple for people to come by and get tested."

Graduate students, faculty and staff who are authorized to work on campus can sign up to participate in the Free Asymptomatic Saliva Testing (FAST) study on the IGI website.

The saliva sampling kit is much like those used by genealogy testing companies such as Ancestry.com. (UC Berkeley photo by Irene Yi)

The IGI researchers hope to analyze the results of the saliva tests and submit an application for an Emergency Use Authorization (EUA) to the Food and Drug Administration (FDA), which would allow them to employ the saliva test clinically.

The FDA has already given EUAs to a handful of saliva-based tests for COVID-19. All are for at-home sample collection; the samples are then returned to labs for PCR (polymerase chain reation)-based diagnostics. UC Berkeley will analyze its saliva samples at a pop-up lab in the IGI, with results returned within five days.

Using CRISPR-Cas proteins, Doudna and other researchers at the IGI are also working on an inexpensive and simpler point-of-care or home test that would give people results within minutes, without having to return saliva samples to a lab.

The IGI was started in 2014 by UC Berkeley and UCSF with the goal of advancing CRISPR-based genome editing, a technology for changing the DNA of cells and organisms that Doudna and French colleague Emmanuelle Charpentier pioneered two years earlier. When California mandated shelter in place, IGI scientists quickly pivoted to create a clinically certified pop-up COVID-19 diagnostic lab.

The testing lab currently employs PCR analysis to search for pieces of the virus in swab samples, now mostly obtained from symptomatic people or those who suspect exposure to the virus. After a robotic system came online this month, the capacity increased to 1,000 tests per day. While the initial focus was students and front-line responders on campus, the increased capacity allowed the lab to expand its outreach to other California communities.

"One of the goals of setting up the testing lab at the IGI was to provide testing to our larger, broader community here in the Bay Area and around California, people who don’t have access to testing," she said. "We have been engaged for many weeks with health care providers that work with people in homeless encampments and nursing homes, as well as (with) first responders and utility workers who are keeping the lights on here in California."


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