AILSA CHANG, HOST:
The Food and Drug Administration says it will soon authorize Moderna's COVID-19 vaccine for emergency use, making it the second vaccine to get the thumbs-up, after Pfizer's, and more are in the works. Even so, we are several months away from having enough vaccine to inoculate most Americans. And joining us now to talk about exactly where things stand is NPR science correspondent Richard Harris. Hey, Richard.
RICHARD HARRIS, BYLINE: Hey, Ailsa.
CHANG: All right, so yesterday, the FDA's advisory committee recommended that the agency authorize the Moderna vaccine. Great. So how soon do you think it'll be before we see people actually getting it?
HARRIS: Not long. Last week, Pfizer's vaccine got the thumbs-up last Friday evening, and it was getting shipped out to hospitals around the country by Monday. And I expect something similar will happen this time around. Together, there should be enough doses for 20 million people to get the first of their two shots before the end of the year.
CHANG: And how much of a difference is there between the Pfizer vaccine and the Moderna vaccine? And would people get a choice of which one they would get?
HARRIS: Right. Well, the technology is very similar. Both appear to be safe and highly effective. The one difference is Pfizer asked to allow the shot in people 16 and older, while Moderna asked for authorization for people 18 and up. So some teenagers could have only one choice. But the advice public health officials give is, if you're offered a shot, take it no matter which one.
CHANG: Got it. OK, and there will - will there be any geographic differences in terms of where they distribute which vaccine?
HARRIS: Possibly. The Pfizer vaccine needs to be stored in super-cold freezers, but the Moderna vaccine can actually be kept fine at normal frigid temperatures and can even last for weeks in the refrigerator. So John Grabenstein at Georgetown University says doctors in rural areas will clearly prefer the Moderna vaccine.
JOHN GRABENSTEIN: It's a testament to the health departments that they've been doing so well getting the really ultracold Pfizer-BioNTech vaccine distributed already in the few days they've been working at it. But it's certainly always good to take friction out of immunization programs.
HARRIS: Clearly, there are a lot of logistical issues still to work through. States aren't getting all the of the first modest distributions that they were expecting, and those problems could well multiply as programs expand to vaccinate tens of millions of people.
CHANG: Well, what I want to know is, does having a second vaccine on the market create any kind of complications?
HARRIS: Yes, potentially. The two products are administered a bit differently. So, for example, if you wait three weeks for shots for the Pfizer vaccine, it takes four weeks for the Moderna shot. Again, here's John Grabenstein.
GRABENSTEIN: The good news is you can have two products. The bad news is, two products make the potential for medication errors.
HARRIS: Errors like giving the wrong dose, since the vaccines do differ. Medical personnel will just have to make sure that they don't lose track of these details.
CHANG: OK, so the Pfizer vaccine and the Moderna vaccine are just the first two vaccines to go out. What else is in the pipeline at this point?
HARRIS: Well, for the U.S. population, there are several others in advanced testing. There's a single-shot formulation by Johnson & Johnson being tested now. And we could learn the results of that sometime in January. AstraZeneca also has a study going on, as does Novavax.
CHANG: OK, and what are the prospects of accelerating the timeline here?
HARRIS: Well, Dr. Michael Mina at Harvard's Chan School of Public Health has an idea for stretching the existing supplies. He suggests that medical researchers immediately start studying whether a single dose of these vaccines would be effective.
MICHAEL MINA: Even if it's only sufficient for a year and we need to give the booster dose a year later, that would get us through the next five or six months in a much better position than we are currently in.
HARRIS: And, you know, during the studies of the Pfizer and Moderna vaccines, there were hints that the first shot was providing some protection. But everyone else got a follow-up shot in just three or four weeks, so it's not clear if the single shot will actually have long-lasting immunity.
CHANG: That is NPR's Richard Harris. Thank you, Richard.
HARRIS: Sure. Transcript provided by NPR, Copyright NPR.