Science Vs - The Delta Variant: How Bad Is It?

Episode Date: August 10, 2021

This delta variant of the coronavirus seems to really be screwing us over. Cases are spiking in the U.S., and we keep hearing about vaccinated people getting Covid. So how worried should we be? And what is it about delta that makes it so sneaky? We talk to public health supervisor Katarina Grande and virologist and immunologist Professor Ann Sheehy to find out. Here’s a link to our transcript: https://bit.ly/37Cn9la  UPDATE 8/25/21 : In a previous version of this episode, we used the word "infected" when it would have been more accurate to use the phrase "get sick." The episode has been updated. This episode was produced by Meryl Horn with help from Rose Rimler, along with Nick DelRose, Michelle Dang and Ekedi Fausther-Keeys. We’re edited by Blythe Terrell. Fact checking by Ekedi Fausther-Keeys, Michelle Dang and Nick DelRose. Mix and sound design by Bumi Hidaka. Music written by Peter Leonard, Marcus Bagala, Emma Munger and Bobby Lord. Thanks to the researchers we got in touch with for this episode, including Professor Michael Toole, Dr. Kathryn Stephenson and Dr. Barnaby Young. Learn more about your ad choices. Visit podcastchoices.com/adchoices

How you going? I'm Wendy Zuckerman, and this is Science Versus from Gimlet. Nope, just kidding. It's me, Rose Rumler, and I'm going to be hosting a few episodes of the show while Wendy's on leave. You'll hear her again soon. We're popping in before our next season because it seems like we're at a new crossroads with COVID. The highly contagious Delta variant now responsible for 93% of all new cases in the U.S. That alarming news from the CDC acknowledging that, quote, the war has changed because of the Delta variant. The Delta variant. It's driving cases back up again, and it has some of us wondering if our vaccines are still working. There is some confusion and concern because those who are fully vaccinated are testing positive. And it kind of feels like we're going backwards.

The CDC called for the vaccinated to also wear masks indoors in high-risk communities. So what's going on here? Today, we're going to look at a couple of big pieces of this puzzle to figure out how freaked out we should be. We're asking, is Delta really escaping our vaccines? And what makes this version of the coronavirus so sneaky? That's coming up after the break. Bumble knows it's hard to start conversations. Hey, no, too basic.

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It's season three of The Joy of Why And I still have a lot of questions Like, what is this thing we call time why does altruism exist and where is jan 11 i'm here astrophysicist and co-host ready for anything that's right i'm bringing in the a team so brace yourselves get ready to learn i'm jan 11 i'm steve strogettes and this is quantum magazine's The Joy of Why. New episodes drop every other Thursday, starting February 1st. What does the AI revolution mean for jobs, for getting things done? Who are the people creating this technology, and what do they think?

I'm Rana El-Khelyoubi, an AI scientist, entrepreneur, investor, and now host of the new podcast, Pioneers of AI. Welcome back. After months of things calming down in the U.S. and going a little bit back to normal, the CDC is now telling lots of vaccinated people to mask back up. So what just happened? To find out what's behind this, producer Meryl Horn and I called up Katerina Grande, a public health supervisor in Wisconsin. Hey, Katerina. Hey, good morning, Meryl. How are you? Good morning. How are you? Good. A couple weeks ago, Katerina was on a routine call with the CDC.

A bunch of health departments were getting COVID updates. And someone at the CDC mentioned something that made Karina do a double take. They said, you know, we're seeing something different with Delta. We're seeing that there may be no difference in viral load of people who have COVID who are and are not vaccinated. This really struck her because while we knew some vaccinated people would get infected, we figured that when it happened, they'd be a lot less likely to spread it around compared to people who weren't vaccinated. But if what the CDC was saying turned out to be true, that vaccinated people can be chock full of virus, that's another story. Katarina was like, uh... Wait a second. Did I...

Did I mishear that? Unless I misheard, that seems like a pretty big deal. But Katarina wasn't just going to sit around fretting about whether this was true. The Delta variant was the main variant in Wisconsin. And the public health department had been doing COVID tests on lots of people,

both vaccinated and unvaccinated, so they could see for themselves. I immediately emailed the UW researchers and I said, let's move on this. Let's look at this a little bit closer. Are we seeing this here? They look back at COVID tests from people who had recently tested positive, almost 300 tests. A quarter of those positives, almost 80 of them, were in vaccinated people. So are these the tests that come from when people just in the community feel a little sick and think like, oh, I should probably get a COVID test and like go to their pharmacy?

Yeah, yeah. Literally, it's our scientists walking down the street or driving over to the lab and picking up samples. The scientists themselves go to like pick up those boxes of swabs? Yes, the grad students. This is where grad students come in. The swabs get run through a machine that estimates how much virus is in there. And it's not a perfect test. For one thing, it can't tell us whether the virus particles are still infectious or not. But it can give a sense of how much virus is there, whether the swab is loaded with virus bits or if there's just a little bit there. And so these Wisconsin scientists compared the positive tests from people who were vaccinated with the people who hadn't gotten the jab. And the results were actually kind of a huge bummer. Yeah, so we found that there was statistically no difference

and that the level of virus in both vaccinated and unvaccinated people was high. So what did you think when you saw those results? Vaccinated people had just as much virus floating around in their noses as people who hadn't gotten vaccinated. This suggests that it's plausible for vaccinated people to spread the virus. Besides Katerina's group, the CDC and other labs have come out with early research that shows the same thing. We saw this in that big outbreak in Cape Cod in the U.S., where more than 400 people got infected, and three-quarters of them were fully vaccinated. All this is why the CDC is now telling lots of vaccinated people

to wear masks indoors again. And it's changed how Katerina thinks about life during the pandemic. Were you kind of like, oh God, we're screwed? Hmm, was it an oh God, we're screwed? I mean, did I think twice of like, oh, God, we're screwed? Hmm. Was it? No. I mean, did I think twice about like, huh, I did go to that really busy concert two weeks ago without a mask and was screaming in an indoor environment. Huh. It definitely ran through my mind of, gosh, this is brand new information. And I kind of wish I had known this information

uh a few weeks ago what what kind of concert was it um this is very embarrassing but for a mental break um I I watched The Bachelorette with a group of friends virtually. And there was a contestant who is a musician and he came to Madison and performed with his little band. So yeah, there's multi-layers of embarrassment going on right here. I mean, I have watched The Bachelorette too. I feel like I need to come out and confess that also. So don't worry. We all watched The Bachelorette. Oh I feel like I need to come out and confess that also. So don't worry. We all watched The Bachelorette.

Oh my gosh. Oh. It feels so hard. For our fellow Bachelorette fans, it was a Connor B concert. Anyway, Katerina said she wouldn't go to another indoor concert right now, even though she's vaccinated. She's also masking up more than before. So she's living more carefully,

even though she told us there's a lot we still don't know. vaccinated. She's also masking up more than before. So she's living more carefully, even though she told us there's a lot we still don't know. We have an idea of, okay, it's plausible that if you have the same level of virus in a vaccinated and unvaccinated person with COVID, plausible that you'd be able to transmit it. But we don't know how efficiently someone could transmit. We don't know how symptoms play a role in this finding. So there are a lot of unknowns. One of the big unknowns is how likely you are to get sick if you're vaccinated. Like, what is my or Katarina's chance of being one of these breakthrough COVID cases?

Well, we can't quite answer that. But we do know that overall, the vaccines don't work as well against Delta. When it comes to exactly how effective they are, the numbers are kind of all over the map. One vaccine expert who's been following the science told us that big picture, she thinks our vaccines could be something like 50 to 80 percent effective at keeping you from getting sick with Delta. Still, though, there is some reassuring stuff coming out. Katarina's study only looked at one day and one test, but she told us about some data from Singapore, which looked at how people's viral loads changed over time. They found that viral loads decreased faster in vaccinated individuals. So that tells us something,

tells us something else, that people who are vaccinated with COVID maybe can still transmit, but not be as infectious for as long if that's the case. That feels like good news that maybe we can hold on to. Very much. Very much so good news. And the other good news is that we know that for the most part, when vaccinated people do get infected, they aren't getting nearly as sick as unvaccinated people. You're way less likely to end up in the hospital or to die if you have the vaccine. So even though this is nerve-wracking for vaccinated folks, right now Delta is still much scarier for unvaccinated people. So when we come back, what exactly makes Delta so much worse? And what else could be waiting around the corner? That's after the break. Welcome back. Today we're looking at the Delta variant, which is now dominating the U.S.

And we wanted to find out what's actually going on with Delta. Like, if you crack open the hood and peek inside, what makes it so special? So for this, we called up Professor Anne Sheehy. She's a virologist and immunologist at the College of the Holy Cross. And she told us that Delta actually has a bunch of mutations, but the most important ones are those that affect a very specific part of the virus. What they're tracking the most and what is likely to be really important are the changes that occur in spike. The famous spike protein.

Yes, right. It never goes away. It's never going to go away. It's never going to go away. Last time we talked to Anne, she told us about a change in spike that scientists were calling the EEC mutation. For Delta, there's another mutation we're zooming in on. It's called P681R. So the P681R, that's the one that's probably getting the most attention right now is trying to figure out, hey, what's different? Do we have any cute nicknames for these new mutations? Not that I've heard. Well, we were thinking that the P681R, that we could call that the permutation.

The permutation, that's right. That's right. And it's like, I like also the play on word of permutation. I just heard that. I didn't even realize that was the joke until just now when I said it. Because it's a permutation of a virus. That is the dorkiest thing I've ever said, actually. Oh, but so nice. So what does the permutation do? This is a little bit more complicated,

but we can break this down easy because people who listen to this stuff are really sharp. Yeah, you guys got this. It all starts when new viruses are born. So let's say you get infected with a coronavirus. You sniff up a virus and it wiggles its way into one of your cells. That virus gets to work making tons of copies of itself inside that cell. Little virus babies. These babies eventually leave and go out looking for new cells to infect. But before they do that, they often get a little sniff from an enzyme. So it has to be clipped by some molecular scissors.

The snip changes the shape of the spike, making it easier for the virus to latch on to other cells in your body. With the old version of this virus, the process was a little bit hit or miss. Sometimes the molecular scissors would bump into the baby virus and make the clip, and sometimes they wouldn't. But with the permutation, it's almost like these baby viruses have a little crease,

right where the scissors need to snip. You can think of it like a perforation. In this case, what the virus has done is optimize those perforations where it's clean, it's beautiful, it's really easy for the molecular scissors to find it, clip, and on you go. It reminds me actually of ripping a paper towel off. Yes, sure. And sometimes it works clean, goes cleanly, like, ah, one paper towel, but sometimes you rip off half the next one or only half the one you wanted. Exactly, exactly. So in this metaphor, the delta variant is like ripping perfect paper towels off every time it wants one.

Zip, zip, zip. Yes. And it's just, absolutely. And then it's not that the original isn't capable of doing it. It's just that it's not as good at it. Yeah. By the way, all this research is pretty early, but this is Anne's best guess at what's going on. And her takeaway is that the PER mutation, along with other mutations in Delta, seem to be upping the chances that each virus your body pumps out will be able to worm its way into other cells. Anne thinks this could

be a big reason why Delta is spreading so quickly, and why it seems to be better at giving our vaccines the slip. There's just more virus for our immune system to fight off. It's kind of a whack-a-mole situation. Other research is suggesting that Delta might also be better at sneaking past our immune system. Scientists are still working it all out. Overall, Anne says, it's not that the mutations are giving the virus superpowers, they're just making it better at doing what it already does. This virus is not like a super virus in the sense that it's so much more stable, it can live on countertops, it hangs in the air longer, like none of that. It's purely at this stage, at least from what we can see,

it's purely traced back to the increased number of particles. And this might be a big increase. Some early research suggests that with Delta, you might have a thousand times more virus in your throat compared to the original strain. So what is that? That's hard for me to wrap my head around that. Does a thousand times higher viral load

mean it's a thousand times more infectious? Um, no, no. Yeah, even if this number is right and people's viral load is a thousand times higher, it doesn't mean you're a thousand times more likely to catch COVID from someone with Delta. Because fortunately, there are a lot of ways the virus can screw up when it copies itself, even if it's really good at making this perforation. So not all the particles you hack up are going to be infectious. Plus, it might also

depend on what your symptoms are, like how much you're coughing. So that all helps explain why it looks like in real life, Delta is about two to three times as infectious as the old strain. So when we say the viral load is this much higher, we don't want people to freak out and think, oh my God, I can't go anywhere. No, that's not true. But what you want to be aware of is that if you're in a place where there is virus circulating, you are more likely to encounter that.

We're also hearing that besides being easier to spread, Delta is also making people more sick. And some early data backs this up. One study found that people who got infected with the Delta variant were twice as likely to be hospitalized as people infected with an older strain. Before we wrap up, there are two more things that we looked into here. First, some people are saying that kids in particular might be getting sicker from Delta. Cases in kids are going up in the U.S., which makes sense because most of them aren't vaccinated. But actually, some early numbers suggest that in

the past couple weeks, kids with COVID were less likely to get hospitalized or to die than they were early on in the pandemic. Still, it's something to keep an eye on. And finally, we looked into booster shots. It makes sense to think that an extra shot might help people with suppressed immune systems, but scientists haven't really tested this. We found one small study that gave a booster to people who'd gotten organ transplants. It found that half of them had ramped up antibodies afterwards, but half of them didn't. And we have no information about what good this might do, if any, for everyone else. All right, so as we look this Delta variant square in its stupid little face, what is the takeaway?

Well, this is all especially bad news for unvaccinated people. The virus is more contagious and potentially more severe. If you're vaccinated and you run into Delta, your chances of getting COVID are higher than we had hoped. But the vaccinated people are still way less likely to get really sick, which means the vaccines are still working hard for us. Ultimately, what this whole Delta fiasco tells us is that we may be dealing with this pandemic for a while yet. And as long as a big chunk of the globe isn't vaccinated,

a lot more people will get sick. And there will be plenty of chances for the virus to evolve, potentially into something worse than what we've got now. There are these other variants floating around. We've heard of Lambda, Nioa. Apparently I have to learn the Greek alphabet now.

Yes! It's like I already had to learn how the immune system works last year. This year I have to learn the Greek alphabet now. Yes. It's like I already had to learn how the immune system works last year. This year, I have to learn Greek. But are we just going to keep getting pummeled with worse and worse versions of this thing forever? No, I don't think so. I wonder if what we will eventually reach is a stalemate, much like we have with influenza. But eventually, it'll probably stabilize. So Anne thinks there's a light at the end of the tunnel.

But how long that tunnel is, nobody knows. That's Science Versus. Hello? Hi Meryl. Hey Rose. How many citations are in this week's episode, Meryl? We have 50 citations. Nice even number. And if people want to check them out for themselves, where should they go? They can look at our show notes or our website and then follow the links to the transcripts. Cool. And can you also, Meryl,

please tell the listeners when we're back for real? Because this is like a special episode, but we're coming back for our regular season soon. Yes, yes. We'll be back on September 9th, which is my birthday. So happy birthday to me. Yeah, maybe you should get the day off. Probably not. Any episodes in particular you're excited about so many um we're doing weight loss finally weight and weight loss weight and weight loss yeah those um therapy chronic pain childbirth childbirth that's a good one yeah all sorts of fun stuff lots of ncvc coming up yes yes if you know you know hopefully we'll see but yes all right thanks so much meryl bye rose bye this episode was produced by meryl horn with help from me rose rimler along with nick delrose

michelle dang and a ketty foster keys were edited by Blythe Terrell. Fact-checking by Aketi Foster-Keys, Michelle Dang, and Nick Delrose. Mix and sound design by Bumi Hidaka. Music written by Peter Leonard, Marcus Begala, Emma Munger, and Bobby Lord. Big thanks to the researchers we got in touch with for this episode, including Professor Michael Toole, Dr. Katherine Stevenson, and Dr. Barnaby Young.