ARI SHAPIRO, HOST:
There are three COVID-19 vaccines currently approved for use in the U.S. Together, they have accounted for more than 81 million doses delivered here. Well, as of today, there is positive news about a fourth candidate - the two-dose shot developed by AstraZeneca and the University of Oxford. Mene Pangalos is AstraZeneca's executive vice president for biopharmaceuticals.
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MENE PANGALOS: The interim results showed that AZD1222 achieved 79% efficacy in preventing symptomatic COVID-19, and it was 100% effective against stopping severe or critical disease and hospitalization.
SHAPIRO: And some more good news. The study did not reveal a link between the vaccine and blood clots, something that recently caused some European countries to suspend use of that vaccine. NPR science correspondent Joe Palca is following today's announcement and joins us now.
Hi, Joe.
JOE PALCA, BYLINE: Hi, Ari.
SHAPIRO: These sound like good efficacy numbers. Tell us more about them.
PALCA: Yeah, they really are quite good, I think even a little bit better than people had expected given some of the other studies that have been done with this vaccine. I spoke with Ann Falsey of the University of Rochester School of Medicine, one of the principal investigators of the study. Now, this study is what's known as double-blinded, meaning neither she nor the participants knew who was getting what. And that information was only just made available, so she didn't learn the vaccine was working until this weekend.
ANN FALSEY: To see these results was absolutely wonderful and particularly the data on the elderly. I think that's an important contribution.
PALCA: That's because there's been some question about whether the vaccine worked in the elderly. And this study showed that it did, and it might even work a tiny bit better than in younger people.
SHAPIRO: And how significant is it that this study did not find a connection between the vaccine and blood clots?
PALCA: Well, it is good news. If they had found a connection, that would be unsettling. But scientists like to say the absence of proof isn't proof of absence. The blood clot issues still could be real but so rare that it just wouldn't turn up in a study of 20,000 people, which is about the number that got the vaccine in this study. You might only see it when millions of people start to get vaccinated, as they have been around the world now.
SHAPIRO: So big question - what's it going to take for this vaccine to be rolled out in the U.S.?
PALCA: Well, it's going to be a while yet. The company said today that they were going to be submitting an application to the Food and Drug Administration for an emergency use authorization in the next few weeks, couple weeks. It was a little unclear. After that, it takes the FDA a few weeks to go through the data, make sure that everything is as it should be and whether they agree with the company on how the data is to be evaluated. And then there's this thing called the VRBPAC, which is a committee of experts outside of FDA that look over the data and decide, yes, I think it's good, or, no, it's not. And then they give an opinion, and then the FDA makes a decision based on all that.
SHAPIRO: And how many doses are we talking about if it gets approved by the FDA?
PALCA: Well, the company said that if it gets authorized by the FDA, there'll be 30 million doses ready to go out the door. And then they said after that, they can deliver 15 to 20 million doses per month after that, so quite a few.
SHAPIRO: NPR science correspondent Joe Palca, thanks a lot.
PALCA: You're very welcome. Transcript provided by NPR, Copyright NPR.
