LULU GARCIA-NAVARRO, HOST:
Mask up, America. Now, that could have been a catchy slogan. Instead, the Centers for Disease Control and Prevention offered confusing guidance this past week. Vaccinated Americans in some parts of the country should mask up indoors again.
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ROCHELLE WALENSKY: It is not a welcomed piece of news that masking is going to be a part of people's lives who have already been vaccinated.
GARCIA-NAVARRO: That's CDC Director Rochelle Walensky. The agency also recommended that students and employees at K-12 schools wear masks this coming school year. The CDC did not explain its reasoning immediately. And when it did, things became even more muddled. Here's Walensky talking on Fox News on Friday.
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WALENSKY: The science continues to change. And while that is neither simple nor easy to convey, it's my responsibility to keep the American people safe. And as that science evolves, I evolve with our - with the CDC - the guidance.
GARCIA-NAVARRO: OK, here is the latest science. Research indicates that the new delta variant is much more infectious and can break through to some vaccinated people. We should stress it is still rare. But unlike breakthrough infections with previous strains, those infected with delta carry tremendous amounts of the virus in their noses and throats. This means the vaccinated may just be as contagious as the unvaccinated. Now, medical experts have stressed nearly all people hospitalized with the delta variant are unvaccinated. Vaccines, we repeat, are the best way to protect yourself from contracting more serious and lethal cases of COVID.
And now corporate America is putting in place vaccine requirements - Walmart, Facebook, Google and Disney, to name a few. And the vaccine rate in the U.S. is now picking up. But in other somewhat discouraging news, it seems that those who've had COVID before may be able to get it again. Nearly 35 million Americans have tested positive for the coronavirus. And while that gives some immunity to the disease, reinfections do happen. But how common are they? I put that question to Dr. Amesh Adalja, an infectious disease doctor from Johns Hopkins University.
AMESH ADALJA: It is uncommon in general. It's not the normal thing that happens. The numbers kind of vary depending upon which variant and which study you're looking at. But it is something that does occur, especially as you get months away from your initial infection, especially as you might be faced with a variant that is a little bit more problematic for your immune system than the original version of the virus you might have been infected with.
GARCIA-NAVARRO: So talk me through that. Basically, you're saying, if I got sick early on in the pandemic, my immunity might wane and especially when faced with something like the delta variant?
ADALJA: Right. What we know is that, with any infection, immunity wanes over time - that the level of antibodies, the level of responsiveness of your whole immune system will start to decrease as it's not been challenged by whatever pathogen you're talking about. And with other coronaviruses - some of the ones that cause the common cold - we know that reinfection is very common. And if you've got a variant, some of the variants might have changed enough of the way they look to your immune system that they can sort of get around some aspects of your immune response. But usually, when you have one of these reinfections, it's usually not something that is very severe because the immunity that you do have protects you, most of the time, from serious illness, hospitalization and death.
GARCIA-NAVARRO: Can you just give me a sort of percentage? Do we know sort of what percentage of people have become reinfected?
ADALJA: It's likely less than 1%, depending upon the numbers that you look at. It's not a very common thing - at least - and it will get higher as we get further out. But right now, it's probably less than 1%.
GARCIA-NAVARRO: If you had COVID, though, and then got vaccinated, how protected are you then?
ADALJA: You're likely to be more protected than just having natural immunity. The data shows that people who have natural immunity - it's not nothing. It definitely is something that will likely protect you from the most severe consequences of a reinfection. But in general, the principle is that the immunity from natural infection is not as strong as what you get from a vaccine, and the vaccine will actually help you boost that immunity that you already have gained.
GARCIA-NAVARRO: What do you think this tells us about the future with COVID? Because as you mentioned, other diseases like the common cold - you can get sick with them year after year. Do you think that's what we're looking at with COVID. Or do you think, with the high vaccination rates, hopefully, that will change?
ADALJA: COVID is going to be with us forever. This is a new respiratory virus that's established itself in the human population. It efficiently spreads. It's not something that can be eliminated. So we will have COVID cases. And it is going to become tamer, more like other respiratory viruses because of the impact of the vaccine. But it's going to be with us. There's no way that COVID magically goes back into bats, and we go back to 2019. And I think that reinfections are going to be something that people deal with, but they're mostly going to be mild. And I even think breakthrough infections in people who get vaccinated are something that most of us are going to experience at some period in time, and most of them are going to be mild because what the goal - the overarching goal - and I think many people forget this - was not to eradicate COVID-19 - that's not possible - but to defang it.
GARCIA-NAVARRO: So you feel that we're well on our way to that being the case and that perhaps in a few years, this might look different?
ADALJA: I do think we're well on the way to defanging and taming this virus. As more people get vaccinated and more people get natural immunity, we are going to see this turn itself into a seasonal coronavirus that we deal with year in and year out but aren't threatened in the way we have been in the past.
GARCIA-NAVARRO: Dr. Amesh Adalja, infectious disease doctor at Johns Hopkins University, thank you very much.
ADALJA: Thanks for having me. Transcript provided by NPR, Copyright NPR.