A rush transcript of "This Week with George Stephanopoulos" airing on Sunday, December 26, 2021, on ABC News is below. This copy may not be in its final form, may be updated and may contain minor transcription errors. For previous show transcripts, visit the "This Week" transcript archive.

       JONATHAN KARL, "THIS WEEK" CO-ANCHOR: And we begin this morning with the president's chief medical adviser, Dr. Anthony Fauci. Dr. Fauci, thank you for joining us. We just heard the details of the president's latest strategy to deal with the pandemic. Let me just ask you bottom line, what in what he announced is going to help deal with the immediate crisis, this rapid spread of Omicron?

       DR. ANTHONY FAUCI, CHIEF MEDICAL ADVISER TO PRESIDENT BIDEN: Well, there are a few things. The one that would be immediate is to make sure, given the rapid spread of this extraordinary variant that we don't get an overrun on hospitals, particularly in those regions in which you have a larger proportion of unvaccinated individuals.

       We want to make sure that given the sheer volume of number of cases that you see now -- every day it goes up and up, the last weekly average was about 150,000, and it likely will go much higher. The President's multi-part component of the response is to make sure that we have adequate backup for hospitals with military personnel, doctors, nurses and other health care providers, making sure that there's enough PPE and that if needed, there's enough ventilators in the national strategic stockpile. Those are the things that are immediate.

       Obviously testing, Jon, is going to be very important, that we get a greater capability of testing particularly when the demand for testing is so high. We're at a combination of the Omicron variant itself, as well as the holiday season where people want to get that extra level of assuredness that they're protected even if you are vaccinated and boosted. One of the problems is that that's not going to be totally available to everyone until we get to January, and there are still some issues now of people having trouble getting tested, but we're addressing the testing problem and that very soon that that will be corrected.

       KARL: So the President seemed to me to be quite defensive when he was asked about that, particularly when David Muir asked him -- asked him about the testing issue. He said that this has not been a failure. But I mean, I've been asking questions about testing so often with you standing with -- with the others at the podium since, you know, the beginning of the pandemic. Testing was a colossal failure in the early days. And why is it that now nearly two years in, we still -- we still don't have affordable tests widely available to anybody who needs it? I mean, this must frustrate you imagined as well.

       FAUCI: Well, obviously it does, Jon. I mean, even with the amount -- I mean, if you look at the beginning of the administration, the beginning of the year, there were essentially no rapid point of care home tests available. Now, there are over nine of them and more coming. The production of them has been rapidly upscaled, and yet because of the demand that we have, which in some respects, Jon, is good, that we have a high demand because we should be using testing much more extensively than we have, even in a situation where you have people who are vaccinated or boosted.

       But the situation where you have such a high demand, a conflation of events, omicron stirring people to get appropriately concerned and wanting to get tested as well as the fact of the run on tests during the holiday season. We've obviously got to do better. I mean, I think things will improve greatly as we get into January, but that doesn't help us today and tomorrow. So you're right, that is something that is of concern.

       KARL: So in terms of omicron, we know how wildly contagious it is. But -- but what -- what is your sense about how, what do we really know about how sick people are getting from this? As you know, there was data out of South Africa that suggested that it was less than 2% of those that were infected were hospitalized. That compared with about 20% that had been hospitalized under the -- under the delta wave. That, by the way, is a country that doesn't have, you know, anywhere near the kind of vaccination level that we have. And we saw some indications out of -- out of England, too, that it seemed to be less severe. What -- what is you -- are you comfortable now in saying that omicron is wildly contagious, but not as severe a disease?

       FAUCI: Well, there's one thing that's for sure that we all agree upon, that it is extraordinarily contagious. It's just outstripped even the most contagious of the previous ones, including delta. There's no argument on anybody's part about that. When we first saw the data from the U.K that it was very clear that the ratio of hospitalizations to cases was lower, interestingly, the duration of hospital stay was lower. The need for oxygen was lower. And when you're in a demographic situation like South Africa, where you have most of the people have gotten infected with prior variants, either the delta or the beta, that it was very likely a combination of perhaps the virus is inherently less virulent, or more likely, there's an underlying degree of residual protection from prior infections of those who've been infected and survived.

       The data from the U.K., and particularly Scotland and England, two separate studies, really confirm that. They're seeing less of a severity in the form of manifestations by hospitalizations. The issue that we don't want to get complacent about, Jon, is that when you have such a high volume of new infections, it might override a real diminution in severity. So that if you have many, many, many more people with a less level of severity, that might kind of neutralize the positive effect of having less severity when you have so many more people.

       And we're particularly worried about those who are in that unvaccinated class that you know, 10s and 10s of millions of Americans who are eligible for vaccination and have not been vaccinated. Those are the most vulnerable ones when you have a virus that is extraordinarily effective in getting to people and infecting them the way omicron is. So even though we're pleased by the evidence from multiple countries that it looks like there is a lesser degree of severity, we've got to be careful that we don't get complacent about that. It might still lead to a lot of hospitalizations in the United States.

       KARL: Right. So as an individual your chance of having severe disease needing to go to the hospital, if you if you get infected with omicron might be less, but because there are so many more of the hospitals could still could still be overrun. Let me --

       FAUCI: That -- yeah, that's the concern. That's the concern.

       KARL: Let me ask you about something else from from the president's interview with with David. David asked about the vaccine, the lack of a vaccine requirement for air travel. There is no vaccine requirement for domestic air travel in the United States. And when the President was asked, should there be one, he said that his team has said it's not necessary at this point. Do you agree with that, that there shouldn't be a vaccine requirement for domestic air travel?

       FAUCI: Well, it depends on what you want to use it for. I mean, vaccine requirements for people coming in from other countries is to prevent newly infected people from getting in to the country. A vaccine requirement for a person getting on the plane is just another level of getting people to have a mechanism that would spur them to get vaccinated. Namely, you can't get on a plane unless you're vaccinated, which is just another one of the ways of getting requirements, whatever that might be.

       So I mean, anything that could get people more vaccinated would be welcome. But with regard to the spread of virus in the country, I mean, I think if you look at wearing a mask and the filtration on on planes, things are reasonably safe. We want to make sure people keep their masks on. I think the idea of taking masks off, in my mind, is really not something we should even be considering, and that's what we meant by it depends on what the goal of getting people vaccinated before they get on a domestic flight.

       KARL: Yeah, and of course the the the airline CEOs were suggesting that, you know, that we may not -- may no longer need a mask. I hear you loud and clear you disagree with that on, on an -- on the airplane. You know, it was interesting on this question of vaccination, I'm sure you saw President Trump, former President Trump said -- came out and said that he had received the booster shot. He actually got booed a little bit by the crowd of supporter -- of his supporters, as he said that. And now, you know, there's another interview he just did with a conservative outlet with Candace Owens, where he really pushed back on the idea that the vaccine is not protecting people. He said that the people going to hospitals are -- are the ones largely that, that haven't been vaccinated. You don't die if you get the vaccine -- those were done with Donald Trump's words. I mean, it'll be interesting to see if his supporters listen to that.

       FAUCI: Well, I certainly hope so, Jon. We'll take anything we can get about getting people vaccinated. I was a bit dismayed when former President Trump came out and made that statement, and his followers booed him, which I was stunned by that. I mean, given the fact of how popular he is with that group, that they would boo him, which tells me how recalcitrant they are about being told what they should do. And I think that his continuing to say that people should get vaccinated and articulating that to them, in my mind is a good thing. I hope he keeps it up.

       KARL: Yeah, let's hope he says it loudly and clearly. Hey, before you go one question with some news this week, that a second antiviral pill, this one by Merck has been approved for emergency use authorization by the FDA. This one not quite as effective as the Pfizer pill, which is 89% effective in preventing hospitalizations and death. Is this -- is this really the breakthrough that you've been waiting for? Do you think ultimately, that our path out of this -- I know the emphasis now is on vaccines -- but, but that, that -- that these antiviral treatments could be ultimately the real silver bullet?

       FAUCI: Jon, I agree with you that a highly effective orally administered -- and that's the critical issue. There are two things that are really encouraging about this approval of these, particularly the Pfizer product, which is about 90% effective in preventing you from getting to the hospital or dying compared to placebo. That's part of the comprehensive approach to this outbreak. Vaccines and boosters, masks and now very importantly, a highly effective therapy is really going to make a major, major difference. We've just got to make sure that there's the production of enough of that product that we can get it widely used for those who need it as quickly as possible.

       KARL: I assume that will be a top priority going forward, right? I mean, possibly including Defense Authorization Act -- Production Authorization Act and the like.

       FAUCI: Absolutely, Jon, absolutely. We've got to get that product into the mouths of those who need it.

       KARL: All right, Dr. Fauci, thank you for joining us and Merry Christmas.

       FAUCI: Thank you, Jon. Thank you for having me.