MARY LOUISE KELLY, HOST:

Back in the spring, the Trump administration bet big on a plan to fast-track a coronavirus vaccine.

(SOUNDBITE OF ARCHIVED RECORDING)

PRESIDENT DONALD TRUMP: It's called Operation Warp Speed. That means big, and it means fast - a massive scientific, industrial and logistical endeavor unlike anything our country has seen since the Manhattan Project.

KELLY: That's the president speaking on May 15. Now the administration is suggesting that Operation Warp Speed may pay off. The CDC is telling states to get ready, that a potential vaccine may be ready to distribute as soon as late October. Well, for some insight into how likely that target is, I'm joined now by Dr. Moncef Slaoui. He is the chief scientific adviser to Operation Warp Speed, one of two men the president has put in charge of the project.

Dr. Slaoui, welcome to ALL THINGS CONSIDERED.

MONCEF SLAOUI: Thank you.

KELLY: How real is that timing? Late October would be the end of next month.

SLAOUI: Well, it's a matter of planning, and the operation has been performing, I have to say, very, very well up to now, even better than I was hoping. There is a very, very low chance that the trials that are running as we speak could read before the end of October, and therefore there could be - if all other conditions required for an emergency use authorization are met and approved. I think it's extremely unlikely but not impossible, and therefore it's the right thing to do to be prepared in case.

KELLY: You're saying it is possible but very unlikely that there will be any kind of vaccine ready to distribute by the end of October, start of November. Am I hearing that right?

SLAOUI: Yes, it's possibility but very unlikely.

KELLY: OK. It's two vaccines that, I understand, the CDC is putting forward as two candidates - Vaccine A, Vaccine B. These are the products being developed by - one by Pfizer, one by Moderna. Can you confirm that?

SLAOUI: Yes.

KELLY: OK. And in terms of where they both are, would this vaccine be introduced before phase three clinical trials have been completed? I mean, I'm asking because it seems like the major question is, will they be safe?

SLAOUI: So the vaccines would not be introduced before the clinical trials are completed. The trials will be completed when an independent data safety monitoring board looks into the data, and they are, of course, separate from the operation, from the NIH, from the government, from everyone involved. And if the data shows statistical significance for the right endpoint of disease in the right populations, then we can submit an emergency use authorization. So the requirements are very high, and there is no intent to file before a demonstration of efficacy and safety in the phase three trials.

KELLY: Before you know that it works and it is safe. I mean, you understand why there are all these questions about the timing...

SLAOUI: Yes.

KELLY: ...And that this beginning of November or late October date being floated at all - many people will ask, is this politics? Is this a calculated push to try to rush some good news - a vaccine, hallelujah, we're saved - to get that out there right before the election? Let me let you just take that on directly. Is this about politics?

SLAOUI: I can tell you that hundreds of people that are part of the operations are here - including myself, of course - are here, 100%, 24 hours a day, seven days a week, to make a vaccine available for the American populations and for the world because we know that between a thousand and now 892 people are dead every day.

KELLY: Yeah.

SLAOUI: And every day that we can be faster, we try to be faster. There is - for us, there is absolutely nothing to do with politics, and many of us may or may not be supportive of this administration. It's irrelevant, frankly.

KELLY: You get the skepticism, though, that this November 1 date, two days before the election, has suddenly popped up.

SLAOUI: But I think - frankly, I think - I get the point. You're right. And my reading of that letter, which I - like you - discovered on the news, is one that says we need to be prepared as of. And I do think there is a possibility that the clinical trials - albeit very low, as I said before, extremely low - but there is a possibility that the trials read out before the end of October. It would be irresponsible not to be ready if that was the case.

KELLY: Dr. Slaoui, how far are we - whatever may come to pass at the end of October, start of November - how far are we from the ultimate goal, which is a vaccine that, A, works, B, is safe and, C, is widely available, that will get us back to normal, whatever that might look like?

SLAOUI: So I think - I firmly believe that we will have a vaccine available before the end of the year, and it will be available in quantities that can immunize subjects with health at the highest risk, which means the very old people - I would say 70 years old and older - and maybe people that are highly exposed in the first line. We may have enough vaccine by the end of the year to immunize probably, I would say, between 20 and 25 million people. And then we will ramp up the manufacturing of vaccine doses to be able to, based on our plans, have enough vaccine to immunize the U.S. population by the middle of 2021.

KELLY: Middle of 2021.

SLAOUI: Yes.

KELLY: That feels a long way away.

SLAOUI: Yes. But you're right because there is a pandemic out there. On the other hand, on the scale of how long it takes to make vaccines, this is incredibly fast. We've prepared all the steps at the same time. We ran them one by one, but we never lost time.

KELLY: Right.

SLAOUI: We literally moved from one to the other within a period of a day. And at the same time, we invested in manufacturing at high risk. And this is really where the U.S. government and taxpayer money has been invested, is to manufacture at risk.

Now, in October or November or December or whenever we end up achieving clinical efficacy based on the studies that are ongoing, we may discover that the vaccine is not efficacious, and we have to throw those vaccine doses. Or we may discover that the vaccine is efficacious, and if that's the case, we will have vaccine doses. We will not have 300 million in December; we will probably have 20, 30 million doses in December and then 15 in January and then 17 in February. I'm inventing numbers here. I'm not giving you the exact numbers - but just to exemplify it, the ramping that will take place.

KELLY: Well, Dr. Slaoui, thank you very much for your time. We appreciate it.

SLAOUI: Thank you. You're very welcome.

KELLY: Dr. Moncef Slaoui - he is the chief scientific adviser to Operation Warp Speed.

(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.