Early one late September morning in Las Vegas, scientist Prem Premsrirut hugged her children goodbye as they left for school and she headed to meetings before flying back to her New York City laboratory where, as one business partner put it, she is working to save the world.
Premsrirut, who grew up in Las Vegas, has developed a saliva-based pool test for detecting COVID-19 that is being used by dozens of schools, universities, sports teams and nursing homes. If all goes according to plan, it soon will be the basis for a new program at Wynn Resorts in Las Vegas.
Her method requires the person being tested to spit through a tiny straw into a small tube, rather than the conventional approach of having a technician insert a swab way up the nose. Saliva samples from two dozen people are processed in one batch, or pool, in her Brooklyn lab.
If the coronavirus is detected, increasingly smaller batches are tested to narrow down the pool and identify the sample with the virus.
The saliva pool test is faster, easier, cheaper and as accurate as a swab test, allowing more people to be tested more frequently, said Premsrirut, founder and CEO of Mirimus biotechnology company.
“If we have a robust testing pipeline, where you can give your sample and have the results provided back to you within 12 to 24 hours, and have meaningful results, we can really start to control the spread of this,” said Premsrirut, who is 40.
“Without it, it’s going to be impossible to reopen schools, reopen businesses and get our lives back to normal.”
The mission of reopening schools has personal significance for the mother of 7-year-old Ivan and 9-year-old Anya. When their school in New York went to a combination of in-person and online classes, Ivan did not thrive in the virtual classroom, Premsrirut said.
So Premsrirut, who is divorced but in a “happy blended family,” brought her children to Las Vegas to live with their grandparents, attend class in person at a private school and be looked after by relatives and her mother’s “army of friends.”
After seeing her kids off to school that September morning, Premsrirut met with representatives of University Medical Center and Wynn Resorts. She is teaming up with them on a program for quick turnaround testing at Wynn through an on-site lab to be run by UMC.
Partnership with Wynn
Wynn Resorts worked with Georgetown University and leading labs across the country to identify promising testing technologies, CEO Matt Maddox said in an interview Thursday.
He ruled out rapid antigen tests that can produce on-site results within 15 minutes but which the Centers for Disease Control and Prevention say generally don’t yield results that are as accurate as lab tests that rely on polymerase chain reaction technology. Both conventional swab tests and the Mirimus saliva test use the PCR technology.
Maddox turned to Yale University to learn about the use of saliva as the basis for testing.
“Spent time with Yale — they’re open book, open source with their lab and what they’re doing — and their data on saliva was very, very, very compelling, meaning as good as swab,” Maddox said. “So that was, I think, kind of the first breakthrough.”
Through Yale, which has a partnership with the Mirimus lab, Maddox met Premsrirut.
“It was really fortuitous when we reached out to Prem that she was from Las Vegas,” Maddox said.
Premsrirut’s family moved to Las Vegas when she was 4 after her mother, an Air Force pediatrician, was transferred to Nellis Air Force Base. She graduated from Green Valley High School and got her bachelor’s degree at the University of California, Berkeley, in biochemistry and molecular biology. She earned a doctorate and a medical degree from State University of New York at Stony Brook.
Using technology developed during her doctoral training, Premsrirut launched Mirimus a decade ago to produce genetically engineered rodents and cells for researchers and biotech and pharmaceutical companies.
“She’s gonna save the world, and I love partnering with people that have big ambitions,” Maddox said.
Later this year, Maddox hopes to have the on-site lab up and running, allowing select customers to be tested the same day they will be attending a show or a meeting. The testing process at Wynn is expected to take only several hours because results will be processed at an on-site lab. The Mirimus lab in Brooklyn can process 5,000 batched samples in four hours.
Other Mirimus clients, such as Dominican University of California, ship their samples overnight to the Mirimus lab in Brooklyn, which has results within a day.
To prevent outbreaks, Dominican, north of San Francisco, tests monthly the 700 students living or attending class on campus.
“It’s so much easier to do repeat testing when students don’t have to come have a swab stuck up their nose, when they’re literally filling a tiny tube with saliva,” said Vice President Marly Norris, who leads the university’s COVID-19 response.
The turnaround for results is far better than the three- to five-day wait experienced by peer institutions, she said.
Another key factor for the university was cost. “We are not a wealthy private university,” Norris said. “We just didn’t see how we were going to be able to make it work. And then, actually, Marin County Public Health, our local public health folks, said, ‘You know, you should really talk to Mirimus.’”
Each Mirimus test costs about $12, as opposed to the $79 to $125 price of other products Norris said she reviewed.
Saliva as solution
Premsrirut said she seized upon the idea of using saliva for the basis of a test after speaking with colleagues in Europe.
“So I went down that road. I started testing saliva and found out that it definitely was a sensitive sample,” she said. “At the same time, Yale was publishing their results in saliva, so it was really side by side” with Yale and Rutgers University in researching the concept.
To scale testing, Premsrirut explored how much a saliva sample could be diluted as a result of pooling and still remain accurate. She also considered how the sample pools could be meaningful rather than random. For instance, when a pool consists of all of the children in a single classroom, if there is a positive result, the groundwork for tracing the contacts of the child with the virus already has been laid.
To preserve confidentiality, which was important to client schools’ parents, the vials with saliva samples are identified only by bar codes, and not names, meaning that the lab does not know the identities of those being tested.
Wynn Resorts, which regularly tests its employees using the swab method, did a side-by-side comparison of swab testing versus saliva pool testing with 300 individuals and came back with identical results.
“That’s when our partnership, I think, really began to kick off,” Maddox said.
As with any emerging technology, there are questions. Mark Pandori, who directs the Nevada State Public Health Laboratory in Reno, voiced concern that pooling samples reduces the sensitivity of the testing. He also said that testing in batches wouldn’t be an effective approach in areas where there is a high prevalence of the virus; in other words, it’s only practical when most of the batches come back negative and retesting samples isn’t required.
Before the lab at Wynn launches, regulatory review in Nevada will be required. Testing through Mirimus lab in Brooklyn is authorized by the New York Department of Health.
Premsrirut said she couldn’t predict the time frame for review. “If everything is under their (UMC’s) permits, it can move rather quickly,” she said. “If the Nevada Department of Health requires all new permitting for another location, that could stall things quite a bit.”
But she noted that with its test, Mirimus had “gone from conception to validation to implementation to commercialization in about six months. I have probably reached every single roadblock you could imagine and just found a way around it.
“Nothing was gonna slow me down because I understand this mission and what we can accomplish by continuing to go for it.”