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Moderna's COVID-19 Vaccine Shines In Clinical Trial


I'm Steve Inskeep with news of a second coronavirus vaccine. We started last week with Pfizer's assertion that early testing showed its vaccine is 90% effective. A new week, new vaccine - today the biotech company Moderna says its experimental vaccine is nearly 95% effective. NPR's Joe Palca is with us to evaluate this. Hi there, Joe.

JOE PALCA, BYLINE: Morning, Steve.

INSKEEP: Is that as good as it sounds?

PALCA: Yeah, I think so. It's very good, especially considering the Food and Drug Administration was prepared to consider greenlighting a vaccine with only 50% efficacy. So scientists who've seen these results so far are impressed.

INSKEEP: How did Moderna determine that it worked so well?

PALCA: Well, it was a big study of 30,000 volunteers. They came from a variety of ethnic backgrounds - 6,000 self-identified as Latinx or Hispanic, 3,000 self-identified as Black or African American. Half got two injections of the vaccine. Half got two injections of an inert placebo. And in order to see if the vaccine works, you have to wait until people get exposed to the virus. Moderna chief medical officer Tal Zaks says that wasn't a problem.

TAL ZAKS: Unfortunately, cases are occurring at high rates in this country. And the paradox of that is that it enables rapid vaccine development because you're able to quickly demonstrate whether the vaccine works or not. And as we've shown today, ours certainly seems to work very well.

PALCA: So there were a total of 95 people who got sick. Ninety were in the placebo group, compared with only five in the vaccinated group. So the vaccine appeared to be working, and it didn't seem to cause any serious side effects.

INSKEEP: Disturbing at the same time that it's hopeful, that we have the right environment for testing a vaccine for that reason.

PALCA: Yeah, exactly.

INSKEEP: Now, Pfizer, we mentioned, had this vaccine that needs to be stored in ultracold freezers, which raised questions about how you practically get that across the country. Is Moderna's vaccine any better in that respect?

PALCA: Yes, it seems to be. I mean, they've done some testing. And they also put out a release today saying that their vaccine was stable for 30 days at what you would consider a normal refrigerator-freezer temperature, about - well, it's about minus-20 centigrade or minus-4 Fahrenheit. And it also stayed stable - I'm sorry. It stayed stable for six months at that temperature and 30 days at normal refrigerator temperatures. So that makes life a lot easier.

INSKEEP: Well, what comes next, then?

PALCA: Well, what comes next is in the next few weeks, the company will consider applying for what's called an EUA, an emergency use authorization. And that means that, under the circumstances, because we're in a pandemic emergency, they can go ahead and give the vaccine out more widely. They have to wait a little longer to get safety data. They're waiting to see if the vaccine actually causes any problems itself. And they want to wait at least two months, until half the volunteers have completed their full vaccine dosage. So it's still a couple days for that to happen and then a couple days for this - or couple weeks, maybe, to get this application together to the Food and Drug Administration. And then the FDA has to go ahead and make its decision about whether to give some sort of authorization, this emergency use authorization.

INSKEEP: Yeah, this process that can take years is being crunched down to weeks, months, even days. But I guess the FDA still has the basic questions - is it safe? Is it effective?

PALCA: Right. And the thing is - people have said, well, are we cutting corners or rushing this to the market? And the answer seems to be no because it's just the process, which is normally, I'll get back to you some time, has been shortened to be, let's do this right away and as fast as we can.

INSKEEP: NPR's Joe Palca, thanks.

PALCA: You're welcome. Transcript provided by NPR, Copyright NPR.

Joe Palca is a science correspondent for NPR. Since joining NPR in 1992, Palca has covered a range of science topics — everything from biomedical research to astronomy. He is currently focused on the eponymous series, "Joe's Big Idea." Stories in the series explore the minds and motivations of scientists and inventors. Palca is also the founder of NPR Scicommers – A science communication collective.