NOEL KING, HOST:
All right, now let's work through what treatments the president is getting and what they tell us with NPR science correspondent Joe Palca. Good morning, Joe.
JOE PALCA, BYLINE: Good morning.
KING: So doctors say President Trump got a first dose of a steroid on Saturday - dexamethasone. What is it?
PALCA: Well, as you say, it's a steroid. It's usually thought of as an anti-inflammatory drug. It's also - it's an interesting choice because according to the World Health Organization and the NIH treatment guidelines, you only give this to people who are having a severe case of COVID, meaning that they're high inflammation, their lungs aren't functioning properly. And so it's a little bit of a strange choice and kind of makes you think that maybe things aren't quite as rosy as the president's doctors are suggesting.
The other thing it does - and this is where it gets tricky treating someone with COVID infection or coronavirus infection - is that it suppresses the immune system. So on the one hand, you want the immune system to be fighting off the infection. On the other hand, you want to reduce the inflammation that can cause lung damage. So balancing act.
KING: We know that the president was also given supplemental oxygen at least once before he left the White House for the hospital. What does that tell us?
PALCA: Well, it tells us his lungs aren't functioning properly. You know, let's think about it. You breathe in. There are little sacs in your air - in your lungs that take oxygen through and put it into the bloodstream. If those aren't working properly, your body isn't getting the oxygen it needs. And so the way you treat that, in some cases, you give people excess oxygen, so it makes it easier for the lungs to function. But once you start giving people oxygen, then you're talking about an illness that is more serious than just, you know, the sniffles.
KING: Yeah. There are two other drugs that we know the president is getting. Both of them are experimental. Tell us what those are and what they indicate or telegraph to us.
PALCA: Well, the first one is something called a monoclonal antibody cocktail. So what's that? First of all, antibodies are these compounds that our immune systems make that help fight off a - recognize a particular virus and help fight it off. So a monoclonal antibody is a synthetic version of an antibody. And these are actually synthetic versions of, in this case, antibodies that were isolated from a patient who had recovered from COVID-19 and then made in the laboratory. And what you do is you take a synthetic form of these and you put it into a compound, and those are infused into the patient, and hopefully it helps them fight off infection.
So that's this Regeneron monoclonal antibody cocktail. Then the second one is remdesivir, which people have heard about it. That's also an antiviral drug. That actually blocks the ability of the virus to replicate. That's usually given for five days. If the course of treatment is going as expected, the president would have had his third treatment last night. We haven't heard that for sure, but that would be the course, normally.
KING: OK. And the president does say - or he said yesterday that he's feeling much better, but he admitted in this video the next few days will be the real test, which - based on everything you've been reporting for six, seven months - yeah, that's right.
PALCA: Yeah. No, what happens is they say seven to 10 days after infection is a critical time, and patients who seem fine can suddenly crash. So you've got to be careful.
KING: NPR science correspondent Joe Palca. Joe, thanks as always.
PALCA: You're welcome. Transcript provided by NPR, Copyright NPR.