NIH Statement Raises Questions About AstraZeneca's Vaccine Data A U.S. trial of AstraZeneca's COVID-19 vaccine may have used outdated information. A statement by the National Institutes of Health says an incomplete view of efficacy data may have been provided.

NIH Statement Raises Questions About AstraZeneca's Vaccine Data

NIH Statement Raises Questions About AstraZeneca's Vaccine Data

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A U.S. trial of AstraZeneca's COVID-19 vaccine may have used outdated information. A statement by the National Institutes of Health says an incomplete view of efficacy data may have been provided.


Throughout this day, we are reporting on a surprise about a new COVID vaccine. Yesterday, AstraZeneca reported positive outcomes for thousands of people who had received its vaccine. Then early this morning, we learned that a government affiliated oversight board has expressed concern. The board questions the way the company is describing its test results. This is an evolving story. And NPR science correspondent Joe Palca has been talking with us throughout the morning. Joe, welcome back.

JOE PALCA, BYLINE: Thank you, glad to be here.

INSKEEP: So remind us, what originally were we told about the AstraZeneca vaccine and its tests here in the United States?

PALCA: Right. Well, these are the results from a study of 30,000 or 32,000 people, some of whom got the vaccine, some of whom got the placebo. And there's a committee that oversees the results of the study called the DSMB. We love acronyms here in Washington. Or at least...

INSKEEP: Apparently.

PALCA: Yeah. So DSMB watches the study. And, in fact, they're the only ones from the get-go who know who got what because everybody else is what they call blinded. They don't get told. But the DSMB...

INSKEEP: Oh, you don't get told if it's a placebo or which vaccine or anything?

PALCA: That's right. You don't want to influence the results one way or the other by knowing what you're getting or by the researcher knowing. So DSMB is the only one that knows. They looked at the data. And they have certain rules for stopping when the efficacy reaches a certain measurement. And they said, yes, we see a sign of efficacy here. You may stop. And they handed the data - or they handed the key to the data to the company. The company looked at the data and said, whoa, this is good. We have a 79% efficacy that our vaccine is protecting people from COVID.

The trouble is that the DSMB said, whoa, hold on a second. That's not what we saw. And they put out a statement, or at least the National Institute of Allergy and Infectious Disease put out a statement quoting the DSMB as saying, we express concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data. And we urge the company to work with the DSMB - that's us - to review the efficacy data and ensure the most accurate, up-to-date efficacy data can be made public as quickly as possible. So...

INSKEEP: Those are such long sentences that I feel we need to translate a little bit here. So we were told yesterday 79% efficacy, which is pretty good for a vaccine. So that sounds good. But then there is this concern expressed, suggesting that maybe if you look at the test results a different way, you don't see 79%.

PALCA: Exactly.

INSKEEP: What is AstraZeneca saying in response to that?

PALCA: Well, that's exactly right. So they're - so the DSMB is saying, look at all the data. Look at the newest data. And the company just put out a release that said the numbers published yesterday were based on a prespecified interim analysis with a data cutoff of February 17. So they're looking back at data that was collected as of February 17. And the DSMB seems to be saying that between then and now, we have more data, which makes your efficacy numbers not look as good. That seems to be what's happening here. And...

INSKEEP: I think we can interpret that as well. That would mean, does it not, that a few more people in this study got sick, got COVID, and so the 79% rate didn't quite hold up?

PALCA: Right. They got sick. And they got sick in the vaccine arm of the study, not the placebo arm of the study. That's why the numbers don't look as good.

INSKEEP: OK. So we still think this is a pretty good vaccine, but maybe not 79%. What are the implications for actually getting this approved in the United States?

PALCA: Exactly. It's still a good vaccine. It may be not quite as good. And this is just a strange turn. And it'll be up to the FDA to analyze the data themselves and come up - or itself - and come up with a decision about granting an emergency use authorization. That may happen in a month or so.

INSKEEP: I guess that means we'll be coming back to you again for more updates. Joe, thanks.

PALCA: (Laughter) Yep. You bet.

INSKEEP: NPR's Joe Palca.

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