SCOTT SIMON, HOST:
There's several different kinds of tests available to detect the virus that causes COVID-19. Researchers are working on more. They want to make them cheaper and easier to use. NPR's Joe Palca joins us now.
Joe, thanks for being with us.
JOE PALCA, BYLINE: Oh, you're very welcome.
SIMON: And what are scientists doing?
PALCA: Well, there are several teams of scientists who are talking about using a tool called CRISPR. You might remember CRISPR. It sort of took the biological world by storm. It's a technique for altering genetic material in living cells, but it can also be used to identify genetic material in viruses. And that's what they're talking about using it here.
SIMON: And what are the advantages of a CRISPR-based system?
PALCA: Well, the advantages are that you can do it fast, and you can do it cheap. And right now, the gold standard test for detecting the virus is something called PCR, polymerase chain reaction. And that requires a rather large machine. And even the smaller machines that are made by some of the diagnostic companies still require special equipment that can be expensive. And the other thing about the CRISPR test is it doesn't use some of the chemicals that have been reported to be in short supply. Apparently, the ones for CRISPR are a lot more plentiful.
SIMON: What else is in the testing pipeline?
PALCA: Well, interestingly enough, the tests that have - are being done now for viral infection look for the virus itself, which is - make sense. But I talked to a virologist named Sara Sawyer from the University of Colorado. And she has a very different approach. She says, think about the five days or so between the time you actually get infected to the time you start experiencing symptoms.
SARA SAWYER: The virus is beginning to establish a factory where it can produce many more copies of itself. And so while that's happening, cells are responding.
PALCA: And she says, essentially, those cells respond. And they kind of give off signal that says, hey, I've been infected by a virus. This isn't good. And they start putting out these protein factors. And those cells are at the back of the throat and in the nose. And so Sawyer thinks that the chemical signals from those cells wind up in your saliva. And she thinks she can make a test that will measure these signals.
SAWYER: We think saliva is kind of the key to moving these tests out of the doctor's office because we're not going to draw our on blood every morning. But we can spit in a cup.
SIMON: That would be a lot easier. How far along is she in developing this test?
PALCA: Well, she was working on a different approach somewhat. She had gotten a grant to - a contract from the Department of Defense to look for any kind of viral infection. And, of course, when COVID-19 came along, she tweaked the program to look specifically for the indication of COVID-19 infection. So she's about to start, or she wants to start a clinical trial that will test a lot of people and see who goes on to develop symptoms and whether or not she can predict that's the case or not.
SIMON: And the CRISPR test that began by mentioning, do we know when they'll be available?
PALCA: Well, the one that was developed at the University of California, San Francisco is built, and it's supposedly going for FDA approval next week or at least emergency use authorization. And then the company says they'll start using it for testing in California and try and get it out to other labs as soon as they can.
SIMON: NPR's Joe Palca, thanks so much.
PALCA: You're welcome. Transcript provided by NPR, Copyright NPR.
