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Dr. Anthony Fauci Talks About 'Alarming' New Data On Breakthrough Infections


Informing this week's changes was an alarming internal slide deck from the CDC. These slides surfaced publicly last night, indicating that the delta variant is as contagious and as easily spreadable as the chicken pox, even by fully vaccinated people. The CDC slideshow summed up the fight against the coronavirus with these four words - the war has changed. And to help us understand this continually evolving situation, Dr. Anthony Fauci joins us again.


ANTHONY FAUCI: Thank you. It's good to be with you.

CHANG: Good to have you with us. So we now know that the CDC's decision to change its masking guidance was based largely on what was learned from an outbreak on Cape Cod. And before we get into that decision, can you just first tell us a little more about why the data from that outbreak in Provincetown was so startling?

FAUCI: Well, the reason that it is startling, if you want to use that terminology, is that we had a considerable number of individuals who were there who were vaccinated who got infected. And clearly, they were transmitting the infection among themselves. So when you have a vaccinated person who gets infected previously, prior to the delta variant, a vaccinated person generally has a level of virus in their nasal pharynx considerably lower than an unvaccinated person. So that would make it unlikely that a vaccinated person who had a breakthrough infection would transmit the virus to someone else.

The fact that you have a high level of virus in the nasal pharynx of an infected person who has a breakthrough, namely was vaccinated but had a breakthrough infection, and is now capable of transmitting that infection to an uninfected person, that is the thing that is a bit alarming in the sense of triggering the change in the guidelines that the CDC...

CHANG: Right.

FAUCI: ...Has put forth regarding vaccinated people and the wearing of masks in indoor settings geographically when you're in a high-risk area.

CHANG: Right. But the thing is, Dr. Fauci, haven't we known for some time now how transmissible the delta variant is? Like, why did it take the outbreak in Provincetown for the CDC to take action and change its masking guidance?

FAUCI: What we did know was how transmissible the virus was among unvaccinated people. So it was very clear that when you compared the delta variant with, for example, the alpha variant, it was clearly considerably more transmissible. The new data show that it is so transmissible that even a vaccinated person who has a breakthrough infection can now transmit it. That is the new data. There's a difference between knowing...

CHANG: Right.

FAUCI: ...That it's transmissible in general versus it's also transmissible when you have a breakthrough infection of a vaccinated person.

CHANG: OK. Well, let's talk about the internal CDC slides that were first surfaced last night by The Washington Post. As we heard earlier, these slides urge officials to, quote, "acknowledge the war has changed." What do you understand that phrase to mean, the war has changed?

FAUCI: Yeah. Again, you know, phrases like that mean different things to different people. I think the simplest way to get people to understand is that we are dealing with a different virus. The delta virus has characteristics that's different than the alpha variant and other variants we've dealt with. So when someone says the war has changed, what it really means, the virus has changed, and we have got to keep up in our understanding and what our policies are related to the fact that we're dealing now with a more formidable virus.

Having said that, the solution to all of this is to get as many people vaccinated as we possibly can. I think the thing that gets lost in the recent messaging about delta and transmission and things like that is that vaccinated people are quite protected. There are some breakthrough infections, no doubt about that, that you expect. But the vaccines are very effective in protecting you and extremely effective in protecting you against severe disease.

CHANG: Well, I was just going to bring that up because I can see someone out there who's hearing about more breakthrough infections with high viral loads and thinking, well, what's the use of getting vaccinated...

FAUCI: Yeah.

CHANG: ...If I can still get COVID and I can still infect others with COVID? So clarify your reassurance to those people out there who are vaccinated.

FAUCI: I'd be happy to do that. There's a really, really good reason to get vaccinated, and that is to save yourself from getting a severe infection that would lead to hospitalization and deaths. There's one striking number that people who choose to remain unvaccinated should remember. In the United States, if you look at all of the COVID deaths, 99.5% of them occur among unvaccinated people, and 0.5% occur among vaccinated people. So if ever there was a statistic that's striking to tell you the difference between a vaccinated and an unvaccinated person, that's it.

CHANG: Finally, if we're going to take this war analogy further, on what other fronts should this war be fought? I mean, should we be considering postponing mass gatherings again? Should we be somewhat returning to where we were during the winter outbreaks, with outdoor masking guidelines...

FAUCI: Right.

CHANG: ...Stay-at-home directives? What do you think?

FAUCI: I don't think we're there yet at all, and I hope we don't ever get there. I believe if we do the things that you and I have been speaking about now at the same time as getting more and more people vaccinated, we can turn this around. You know, it is one of those things that sometimes you have a problem in a situation in a public health arena where you don't have an effective intervention. That's very frustrating. Right now, we have an intervention that could turn all of this around, and that's what we've got to do.

CHANG: Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, thank you very much for joining us again.

FAUCI: My pleasure. Thank you for having me. Transcript provided by NPR, Copyright NPR.

Ailsa Chang is an award-winning journalist who hosts All Things Considered along with Ari Shapiro, Audie Cornish, and Mary Louise Kelly. She landed in public radio after practicing law for a few years.