The Daily - Breakthrough Infections, Explained

Episode Date: July 26, 2021

For the past couple of weeks, some Americans have reported a curious phenomenon: They have caught the coronavirus despite being vaccinated.Vaccines are still doing their job by protecting against serious illness and hospitalization, but the frequency of so-called breakthrough infections has surprised experts.How do such cases happen, and what risks do they pose?Guest: Apoorva Mandavilli, a science and global health reporter for The New York Times. Sign up here to get The Daily in your inbox each morning. And for an exclusive look at how the biggest stories on our show come together, subscribe to our newsletter. Background reading: Breakthrough infections are still relatively uncommon, experts said, and those that cause serious illness, hospitalization or death even more so.While being fully inoculated protects against serious illness and hospitalization from Covid-19, no vaccine offers 100 percent protection, and vaccinated people may need to take a few more precautions. Here’s what you need to know.For more information on today’s episode, visit nytimes.com/thedaily. Transcripts of each episode will be made available by the next workday. 

From The New York Times, I'm Michael Barbaro. This is The Daily. Today, as the highly contagious Delta variant rips through the United States, a growing number of vaccinated Americans are testing positive for COVID-19. are testing positive for COVID-19. My colleague, Apoorva Mondavili, on the science and risk of breakthrough infections. It's Monday, July 26th.

Apoorva, how did this concept of breakthrough infections first arrive on your radar? I started to get emails from some readers telling me that the things I was writing about the vaccine being as good as they are were wrong. At first, these were just emails from one person here, one person there saying I was vaccinated and I got infected. But then a couple of weeks ago, the pace started to pick up. And in the last 10 days or so, I got a whole bunch of these. And the thing that caught my attention in those emails is that they weren't just talking about one person. They were now describing groups of people who are all vaccinated and getting infected. And that was new and also a little worrisome.

So I wanted to talk to them to see what was going on. And what did you find? So there was one family that all went to Athens, Georgia for a sort of mini family reunion. And when they got there, some of them shared a car ride for a few hours. And when they came back, they were all infected, all vaccinated. Four adults and one kid. There was also this wedding in Oklahoma. This woman wrote me a very long and detailed email explaining how she and her friends had gone to a bar for a bachelorette party. And by the end of her wedding, 17 guests were infected and 15 of them had been vaccinated before. And then finally,

you may actually have heard about this big cluster in Provincetown, Massachusetts. They have this massive 4th of July celebration every year. And this year, apparently, was even more massive than usual. Longer lines, more crowded bars, more partying. And at the end of it, there were a lot of infections. 256 right now. And about two-thirds of them were among people who had been vaccinated. And the thing that struck me about all of these examples that I'm describing to you is that the people who got infected had symptoms.

It wasn't just that they had become infected, which I think we sort of expect. It's more that they actually felt a little bit sick. Hmm. So here are vaccinated people not just testing positive for COVID-19, but feeling unwell, getting some level of sick. So a pretty worrisome kind of breakthrough infection. Right. And I want to be clear, none of these people were hospitalized. None of these people were severely ill. But they did have, you know,

the loss of taste and smell that we were hearing about last year. Some of them had colds and sniffles and allergy-like symptoms, and some of them were really tired and had to take a couple of days off work. So it wasn't entirely trivial, but it was also not probably what they would have experienced if they were not vaccinated. they do feel like they violate our sense of security that came with the vaccine.

On another level, they don't seem entirely unexpected because we were always told that the vaccines weren't going to prevent everyone from getting an infection. That's right. What the vaccines really promise, and they have delivered on this, is that if you're vaccinated, you will not most likely get sick enough to have to be hospitalized or die. If you look at the numbers of people who are hospitalized, a very, very small proportion of those people have been vaccinated. So the vaccines are protecting people for the most part.

I think what has surprised me anyway, and some of the experts I've spoken with, is the frequency of the breakthrough infections. I think we expected people to get infected, but maybe not quite this often. It's hard to say whether it's often because people are so surprised that they're talking about it more, or whether it really is happening more frequently. Either way, we're hearing about a lot of breakthrough infections, and a lot of it is probably because of the Delta variant. And what we're finding out about it is that it is more contagious and causes people to have a lot more virus in their bodies than other versions of the virus that we've seen. So it might be that everything we were told applied to previous versions of the virus, and some of that

now has to be adjusted for this incredibly contagious variant that we're seeing. And what is it, if we think that it's correct to assume that Delta might be leading to more breakthroughs about Delta that would make it more capable of breaking through? So one thing that scientists have been reporting about Delta is that it leads to a much higher viral load. So people who become infected with Delta seem to have a lot more virus in their bodies than they would have if they had been infected with some other variant. And also they seem to be infected for longer. And both of those things mean that you have a lot more opportunities to pass the virus onto somebody else. If you're vaccinated and you're around somebody who's infected with Delta,

you are just exposed to more virus and for longer. And so it's more possible that at some point your immune system gets overwhelmed by the amount of virus that you're seeing and you do end up getting infected. So Delta creates a larger viral load. and that we have to think in combination with the fact that many of us are behaving differently now. We're socializing more, we're socializing without masks, we've been told we don't need to wear them. That may be contributing to this set of breakthrough infections. That's a really important point. We probably have the least amount of restrictions we've had throughout this pandemic. I mean, essentially, we were told to go back to normal. So that's what people have done. They have gone back to normal. They're socializing everywhere. They are going to eat indoors. They've stopped wearing masks indoors. All of those things

are also probably contributing to what we're seeing. So I guess the question is, just how broad a phenomenon is this, these breakthrough infections, and how worrisome is it really? Because from everything you just said, Delta may pack a greater punch. It may make it more likely that you could have a breakthrough infection. But the infection is probably, if you're vaccinated, going to be very mild. So how should we think about that? We don't know how widespread it is because since May, the CDC hasn't really been tracking

breakthrough infections unless somebody gets really sick and is hospitalized or is dying. They are looking at results from smaller studies of breakthrough infections, but they are not tracking this at a national level in a systematic way. Why not? Because we knew that breakthrough infections were a possibility and we expected enough of them that it would have been a waste of time for the CDC to have been tracking every single one of them, or at least that was the thinking then. Of course, now it looks like maybe it would have been a good thing to track them just so we could at least say how much more frequent it is with Delta than with any other variant. But even with that uncertainty of not knowing how widespread it is, we can at least see that people who are vaccinated still don't have much to worry about. The uncertainty really is in how likely somebody who is vaccinated and infected

can pass the virus on to somebody else. That's really, I think, where the uncertainty starts to play a bigger role. And why does that uncertainty matter? The uncertainty of how and how much an infected, vaccinated person ends up spreading the virus? how much an infected, vaccinated person ends up spreading the virus? On a population level, it matters. Because if a lot of vaccinated people are spreading the virus to others, then it's another whole source of cases that we hadn't really considered. That's a whole other set of infections that we have to worry about.

And on an individual level, some of us have kids. Right. And elderly parents. And we may have relatives or friends who are immunocompromised, or we may come into contact with somebody who is unvaccinated for whatever reason. And so even if we are vaccinated, if we can spread the virus to others, we're putting all of those people at risk. So we do really need to find out how often this is happening and how much virus we might be passing on to someone else. Mm-hmm. What you're describing is a very unsatisfying moment where there are breakthrough cases

because CDC doesn't track them. We don't know how many there are, and we don't know exactly how much a vaccinated, infected person, someone experiencing a breakthrough infection, is spreading that virus around. So that's a lot of uncertainty. It really is.

And it's a bit maddening because it felt like we had gotten to a point where we got to know this virus a little bit. We knew what it could do. We knew what we were facing. And Delta has really changed that entire calculation. There are just so many more questions than I think we expected to have at this point. And it feels a little bit like an inflection point, another one, where the country could go in either direction.

We'll be right back. So, Apoorva, you just said that we're at an inflection point, another inflection point in the pandemic. So let's talk more about that. The last time we had you on the show, you had told us that it seemed the pandemic was becoming endemic, which in some ways felt like progress because it meant that there might be flare-ups here and there, mostly in small ways in vulnerable, unvaccinated communities. But I'm wondering now if the transmissibility of Delta and what we're learning about these breakthrough infections of the vaccinated changes our understanding of this. It would seem that it does. It really does.

When we had that conversation, it seemed like we were in a very good place because we had vaccinated a certain proportion of the population. And we thought we knew what the virus would do given that percent of the population being protected, that it would only flare up in areas where the vaccination rate was very low. But now, if we're talking about this incredibly contagious variant, and we're talking about maybe vaccinated people also contributing to the spread, it's not going to be quite so isolated anymore. So I think we're going to have to put off that concept of the virus being endemic for a bit longer. And so as a result, how do we live in this not endemic world, but this kind of longer term pandemic world? What kind of adjustments

will be required to inhabit that space? The most important thing we should really do is get those vaccination rates up. Right. We have to reach 70, 80, 90 percent. We have to get to all of the people who are actually willing to get the vaccine but just haven't had a chance yet. That's something like 10 percent. So we'll gain 10 points there. There are another 10 points gained if we get to all the people who are just hesitant, who have questions, who are waiting to see and are maybe a little afraid. And those people could be persuaded maybe by the right kinds of leaders speaking to them, by more Republican leaders, for example, talking about vaccination more often in a positive light, or church leaders or local leaders talking about it. And then there's that last 20% or so of people

who just do not want to get vaccinated, and maybe we won't get to them. But even if we can get to this other 20%, I think we have a really good chance of pushing this virus back quite a bit. Okay, so that's vaccinations. What else are we going to have to do in terms of adjustments? This is going to be very unpopular, but I think we all need to be wearing masks again, even those of us who are vaccinated. The last few days, I've been talking to a lot of public health experts, and every single one of those people has told me that they do wear masks indoors, that they in fact never stopped, that they wear masks indoors in places where there might be a lot of people, but that they also socialize mostly outdoors.

That really took me by surprise. But what they're saying is that Delta is now enough of a threat that even people who are vaccinated should be thinking about wearing masks when they're not at home. Hmm. So these experts are telling you because of Delta, because of the risk of breakthrough infections, masks should now be put back on

in places like schools, workplaces, grocery store? All of those, and also outdoor places like sports arenas and concert stadiums. Huh. Where people are packed in tight. That's right. Apoorva, you know this. This is not what the CDC is telling us.

The CDC, which is the authority on all these things, is explicitly saying that it's not advising us to wear masks indoors. that it's not advising us to wear masks indoors. And as a result, I now go to the local grocery store and don't always wear a mask. So why is there now a disjunction between what these experts are telling you and what the Centers for Disease Control and Prevention is telling the whole country? Well, Michael, the CDC guidance was always controversial.

Even when they came out with it, a lot of people were saying there's still so many unvaccinated people. Is this really wise? And I think what's happened now, now that we know about these breakthrough infections and especially now that we know about Delta, it's really seeming like we should all be wearing masks. That's what these experts are telling me. Like, we should all be wearing masks. That's what these experts are telling me. And I think the CDC is under a lot of pressure from the White House and from public health experts to revisit this guidance and to maybe change it. But in my conversations with the CDC, when I've asked them about this, they've been pretty

firm. They've said there is no new evidence to have them change their decision. And so they don't have any plans of changing their mask guidance. What they've said to me is that their guidance already allows local jurisdictions to make decisions based on what's happening in their community. And so a given state or a county might decide to do something differently. But at a national level, the CDC is sticking to its guns. So CDC says that this can and should be dealt with at a national level, the CDC is sticking to its guns. So CDC says that this can and should be dealt with at the local level. So how are local governments dealing with the question of masks and Delta right now?

Like so much else in this pandemic, Michael, it's very patchy. Some local governments are being very proactive and reacting very quickly to rising rates and asking their residents to wear masks again. L.A. did this. The Bay Area is moving towards it. Provincetown reinstated a mask advisory and is considering a mask mandate after they had their outbreak. But on the other hand, Arkansas still has a ban on mask mandates. So, so much depends on who the leader is, how much access they have to public health experts, how much they believe in science, how inclined they are to take action quickly. So, I want to inhabit for just a moment skepticism of the idea that everyone's going to

have to put masks back on. And I think that skepticism would come from people who think to themselves, vaccination means we're at relatively low risk of getting sick. And meanwhile, our own government is telling us we don't need to wear masks. So what would you say to that? What do the experts you're talking to say to that skepticism that we don't really have

to put masks back on in this moment? And we don't want to. It is going to come down to a very individual level. You know, one expert I talked to made this analogy of driving and that you'd wear a seat belt when you drive because that's what's safe. So if you think of the vaccines as the seatbelt, for some people, that's more than enough and that's all they're going to do.

But other people may want to have airbags in front, airbags on the side, may want to stay very close to the speed limit and never speed. It really depends on every person's risk tolerance and what they're willing to chance. I do want to come back here to the idea that vaccinated people have nothing to worry about, to say that they have mostly nothing to

worry about. But some vaccinated people have been sick enough to have to miss work. And there is also the possibility of long COVID, which we know so little about. So it's not that you are entirely risk-free if you're vaccinated and do get infected. So Apoorva, how should we be thinking about this strange moment that we're in? Because I think a lot of vaccinated people see this moment as pretty disorienting. I go back in my mind to President Biden saying that July 4th was Independence Day from COVID-19. He said that. And now instead of feeling like we've achieved independence from the virus,

we're talking again about maybe having to put masks on. And we're talking about breakthrough infections. So how do you think about this moment? And how should we all be thinking about this moment? I wish I could offer you more clarity, but honestly, this is also disorienting for me. And I think for a lot of the experts I've talked to, the uncertainty makes it really difficult. Earlier this summer, it felt so good. It was almost euphoric. You know, we really felt like we were coming. So good. Yeah. I mean, coming to the end of this, it seemed like, oh, I see it now. I see where we're going.

But now, we had heard experts say that we were probably going to see infections in the fall again, but we thought it was going to be these small, sporadic outbreaks among the unvaccinated. And the numbers are going up a little sooner than we thought and a little faster than we thought. And these breakthrough infections in vaccinated people are a bit of a surprise. So I think it's not really clear where we're headed. I will say that wherever it is,

it is not going to be as dire as it was before because we already have so many people vaccinated. I think when you look worldwide, the places that have really suffered with Delta are places where very few people are vaccinated. It's Africa. It's a lot of countries in Europe, Israel and the UK and us. We are in really the best shape to be fending off any variant of this virus, including Delta. But it is going to probably get a little bit worse than we thought it would. And not knowing exactly where that point lies, that was disorienting. Hello, Pura. Thank you very much. As always, we appreciate your time.

Always a pleasure. As of Sunday afternoon, the average number of new infections in the U.S. had surpassed 50,000 a day, four times the rate of just a month ago. We'll be right back. Here's what else you need to know today. Here's what else you need to know today. The Times reports that in a major shift, the Biden administration increasingly believes that the most vulnerable Americans will need a booster shot of the COVID-19 vaccine to protect against infection.

Such shots would be given to those 65 or older or with compromised immune systems. The booster shot would consist of a third dose to those 65 or older, or with compromised immune systems. The booster shot would consist of a third dose of either the Pfizer-BioNTech or Moderna vaccines. The new thinking stems in part from research suggesting that the Pfizer vaccine is less effective against the virus after about six months. Today's episode was produced by Rob Zipko, Rachel Quester, Stella Tan, and Daniel Guimet.

It was edited by Dave Shaw and Lisa Chow, engineered by Chris Wood, and contains original music by Marian Lozano. That's it for The Daily. I'm Michael Barbaro. See you tomorrow.