AILSA CHANG, HOST:
A Food and Drug Administration advisory committee is preparing to vote on whether to recommend Pfizer's COVID-19 vaccine for emergency use in the U.S. The vaccine has already gotten the nod elsewhere, including the United Kingdom and Canada, and today's vote could determine the fate of the vaccine here. Joining us now with the latest is NPR science correspondent Richard Harris.
RICHARD HARRIS, BYLINE: Hey, Ailsa. How are you?
CHANG: Good. So what's the latest on this meeting that's been going on - what? - all day?
HARRIS: I know. The committee is still in the thick of it right now. They're raising a lot of technical questions and hearing from Pfizer executives as well as officials at the FDA. But they haven't yet gotten to the big question, which is whether the benefits of the vaccine appear to outweigh any risks. Judging by the tone of their questions, they seem to be strongly in favor of giving the vaccine a thumbs-up, but we haven't gotten there yet.
CHANG: OK, well, what more have we learned about side effects? - because we saw earlier this week that - what? - two volunteers in the U.K. had some strong reactions to the shot, right?
HARRIS: That's right. These two people knew that they had severe allergies, and they apparently had strong allergic reactions to the shot, though they were prepared for a bad reaction and were treated on the spot. Now, that kind of reaction was not seen in the 20,000 or so people who got the Pfizer vaccine in the company's big study. Dr. Susan Wollersheim from the FDA said there are side effects, to be sure, which sounds a lot like the kinds of side effects people get from other vaccines, ranging from sore arms to headaches and achy joints - things like that. And here she is.
SUSAN WOLLERSHEIM: In our age group, fever - generally mild to moderate - were more frequent following dose two than following dose one.
HARRIS: People with known serious allergic reactions were actually excluded from this study because of concerns over side effects, so that leaves a big question mark about who exactly should be warned to be careful about taking the vaccine. Dr. Wollersheim said as a result of the experience in Britain, the FDA has asked Pfizer to closely track any reports of serious allergic reactions.
CHANG: OK, well, beyond this big question of whether the vaccine is safe, whether it's effective, what else of interest has come up at this meeting?
HARRIS: Well, one of the most interesting questions is what to do about ongoing vaccine studies once there's a vaccine that's widely available to the public. Scientists would like to see the studies continue because there's still important stuff to be learned about vaccines. But, you know, the participants have the right to opt out of the study at any time. Dr. Steven Goodman from Stanford was called in to talk about this dilemma. Here's how he framed it.
STEVEN GOODMAN: So as long as there's still important things to learn about the vaccine, placebo-controlled trials should not be regarded as unethical. However, they might be infeasible.
HARRIS: Infeasible because people may simply not want to continue in the study if they can simply sign up to get a vaccine.
CHANG: Interesting. Well, speaking of ongoing studies, what's going to happen to the people in the Pfizer study who got the placebo?
HARRIS: Right. There's something like 20,000 participants who got a placebo shot.
HARRIS: We don't know who they are right now. But they can opt out of the study at any time, in which case they will simply wait their turn until their age group comes eligible to get a vaccine at a doctor's office or a pharmacy. But scientists hope they can find a way to keep them in the study by maybe giving them the vaccine as soon as their age group would be eligible outside of a study. And that could at least provide some more months of data.
CHANG: OK. Well, of course, today we're most eager to hear the committee's formal vote. But assuming it is strongly in favor of the vaccine, what happens next, Richard?
HARRIS: Well, the FDA usually takes advisory committee votes under consideration and mulls them for a while. But given the importance of getting a vaccine out the door quickly, it's quite possible the agency will make its final decision quite rapidly. And whenever it does, the Pfizer vaccine will be ready to go. And by the way, the FDA is going to go through a very similar process just next week as it goes through the review of the Moderna vaccine that they're also on the verge of approving, perhaps.
CHANG: That's right. That is NPR's Richard Harris.
Thank you, Richard.
HARRIS: Any time. Transcript provided by NPR, Copyright NPR.