STEVE INSKEEP, HOST:
These weeks we are spending at home are just the first phase in a long campaign to outlast the coronavirus. Public health experts expect it to be a long campaign because we are likely to have to wait for a vaccine. So why is creating a vaccine so hard? NPR's Joe Palca has been asking. Hi there, Joe.
JOE PALCA, BYLINE: Hi, Steve.
INSKEEP: And it is natural for people to ask, as they're stuck at home, what takes so long?
PALCA: Yeah, and I understand that. And the real question is how come it's going so fast? Or it could be. Because in the past it used to take five to 10 years to make a vaccine, and now people are talking about a year or 18 months. So it's really going faster than expected.
INSKEEP: OK. So does that mean we're just all being wildly optimistic or have scientists really found some way to speed up the timeline?
PALCA: Yeah, they really have. I mean, in the old days, what used to happen is if you knew a virus was causing a disease, you'd have to isolate the virus, you'd have to grow it in the lab, you'd have to modify it, you'd have to formulate it into some sort of a vaccine, but you'd all be doing steps that take a long time. You can't tell a virus grow faster. But now in the world of DNA, the virus sequence, the DNA sequence, or in this case RNA sequence of the virus, came out almost weeks after the virus was identified. And what that means is, Steve, they can identify the part of the virus that causes the immune response because that's all you're interested in. You don't want the whole virus in a vaccine. You want the virus part that causes the immune response. They were able to isolate that fairly rapidly, and it's a protein that they can work with.
INSKEEP: OK. So if they're rapidly able to identify the protein that's the key to defeating this thing, why would it be so hard to then find the way to defeat it?
PALCA: OK. So the thing is, as I said, you put the protein into a human being, and the human being's immune system recognizes the protein and starts to mount an immune response. But you can't just take the protein and shove it into a needle and put it into somebody's arm. You have to package it in a way that the immune system will see it for long enough so that it will begin to make an immune response. And there are a number of ways to put that protein into a person. You could just put it in as an injectable patch. Some people think that might work. You could put it into an inactivated virus that will make copies of it once it's inside of you. You could put it into a - what's it called a DNA vaccine, so the DNA that makes that protein goes into somebody's arm and hijacks the person's cells, a little bit like a virus does, to make just the protein. You can put in RNA. You can give them a pill. There's just a variety of different approaches that people are going to try.
INSKEEP: And they will all take time, I suppose. You're reminding us here that a vaccine doesn't necessarily kill a virus or destroy a virus directly. It gets the body to go after the virus in the proper way.
PALCA: That's right.
INSKEEP: But what is the optimal kind of vaccine?
PALCA: Well, you want one that's safe. You want one that generates a strong and lasting immune response. You need to be able to manufacture it. Sometimes you come up with a brilliant idea of how to package the virus and you just can't make it at a scale that would be useful. You want to have a vaccine that doesn't require special handling. You don't want to have to keep it in a cold storage the entire time until it goes into somebody's arm. You want to make sure that you don't have to administer it more than once. You want to make it an easy to administer. Maybe a shot would be easy. What about a nasal spray or maybe just taking a pill?
INSKEEP: Is somebody - in a few seconds - is somebody close to testing on people?
PALCA: Yeah. There's actually three companies testing on people, two are still in the stage where they're looking only to see if it's safe and one, a Chinese firm, is actually gone to the next stage where they're looking for safety and maybe a bit of seeing if it generates an immune response as well.
INSKEEP: Joe, thanks for the update.
PALCA: You're welcome.
INSKEEP: NPR's Joe Palca. Transcript provided by NPR, Copyright NPR.
