Should You Get an Antibody Test?

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S1: So I want to I wanted to ask you, I guess, first off, why did you decide to get an antibody test? I mean, the main reason I got an antibody tests does because my editor asked me to get the antibody says that Shannon Paulus, who writes about science for Slate and her editor, asked her to get one of these tests because Shannon has spent the last few months trying to answer basic questions that everyone seems to be asking. What type of mask should you wear if you need to wear one when you run, whether you should pay attention to some of the weirder symptoms of the virus this week? My question is, should you bother getting an antibody test? That’s a test that can show whether someone has been exposed to the novel coronavirus in most diseases. The presence of antibodies signals immunity with coalbed scientists think there’s probably some kind of immunity, but they don’t know how much or for how long. If you had a positive test, you could potentially donate some of these antibodies to help patients who are currently sick and fighting the virus.

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S2: I was also just extremely curios and interest in getting one because I live in New York and I’ve been quarantining in Park Slope and I hear sirens all the time and I’m not allowed to do anything and I don’t really have much else going on yesterday. So I thought, hey, I’ll see if I had the novel Corona Virus maybe today.

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S3: Did you have to make an appointment or did you just. Were you able to just show up? Just showed up?

S2: Yeah. Just a spur of the moment, put some things in a purse, which felt really good, like a Kindle in case I had to wait. I walked over. There’s so many lives in my neighborhood now. So as I was walking over, I had this sense of like, all right, there are like a dozen people waiting to get onto a chase bank. Like, what does this mean for my chances of getting an antibody test today?

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S3: As it turned out, the chances were pretty good.

S1: There was only one person ahead of her in line at the urgent care chain, which was offering the tests. How does the antibody test work that you took? I’ve had the swab for Kovik Nego way up your nose, but this is different.

S2: Yeah. So this is just a normal blood jaw.

S4: They just put a rubber thing around your arm and poke a needle to find a vein.

S2: And for me, they always have to do it a lot. And it kind of hurts that. It was extremely normal. Like I’ve done this a thousand times. You’ve done this a thousand times.

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S1: A doctor took her blood. They made the usual small talk. And normally when you’re getting blood drawn. This is the point where a doctor says, okay, you’ll hear back in a few days. And based on those results, then they tell you what to do. But when Shannon asked what she’s supposed to do with her results, you just shrugs and says you can’t really do anything with them.

S2: And I said, well, could I donate Klausmeier if I’ve had it? And he says, Yeah, but you’re going out to a couple of places to do that. And he sort of said sarcastically, something like. Of course, there’s no central a place where you could you. Wow. You seems kind of out there saying, well, that I was. As to why we were there.

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S1: That uncertainty comes from two things, not only as we mentioned, is it unclear to what degree corona virus antibodies confer immunity, but also the antibody tests aren’t completely accurate yet. Some are 90 percent accurate. Some ninety five. They might signal that you’ve had the virus, but they’re not a sure thing. For Shannon, despite the caveats, that doesn’t mean the test has no value. You’re a science reporter. If this thing comes back and says. It’s positive. Yes, you have antibodies. What do you think?

S4: I’m going to feel really good if it comes back and has antibodies. Even though I know it, but that doesn’t really mean anything. It doesn’t mean anything in terms of what I’m going to be allowed to do or what I should do or how I should. Consider myself in relation to this global pandemic. It’s not a piece of hard information.

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S1: Still, the test has an emotional appeal.

S4: I’m just so worried all the time like everybody is. And even it so much durance that I’m not going to pick this thing up.

S2: When I’m here, I’m like my one giant grocery store. Every week or so, like I’d still be early nights.

S1: After we talked, Shannon got her results and she recorded herself right after they came in. City M.D.. By the way, is the name of the urgent care chain where she went.

S5: I’m looking at my city at MGE results now. They’re negative. I’m bummed. I’m like clinging to this little line in these paragraphs of disclaimer that says negative results do not preclude acute SaaS cove to infection, which means that he could have had it a while ago. Man, no bodies could be gone or could just be a false negative because these tests served. I’m trying to rationalize that. I’ve already had it and then I’m safe. I’m doing that. I just wanted some little like. Bit of certainty or good news to cling to, even if it was sort of false.

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S6: Yeah, that’s on.

S7: I get it. I live in New York. I worry all the time. And I thought about getting one of these tests, even though I know they’re imperfect. This week I got two ads for them and my email and I was tempted. Right now, we all want answers, reassurance that maybe we’ve already had the virus without knowing it. Hope that we can be around other people.

S3: That hope comes from this idea of immunity, which feels like a holy grail these days. Today on the show, we’re going to talk about immunity and the role antibody testing plays. In that Shannons experience is one half of the equation. The individual hope for a positive test. And immunity. But there’s another side to those results. What they mean on a population level for our scientific understanding of how this disease behaves and who might now be safe. I’m Lizzie O’Leary, and you’re listening to What Next TBD. A show about technology, power and how the future will be determined. Stay with us.

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S1: After talking to Shannon about her experience getting an antibody test, I kept thinking to myself, what’s the point if we don’t know yet that antibodies guarantee some type of immunity and if the tests themselves have issues with accuracy, why get one in the first place? And it turns out the answer to that question has to do with scale. It’s about populations, not individuals. Scientists can study these antibody results, also called sero surveys, and learn about the corona virus through the numbers in aggregate. I wanted to talk to a scientist who spends their time analyzing and interpreting this data. So I called up Natalie Dean. She is an assistant professor of bio statistics at the University of Florida. She specializes in emerging infectious diseases and has studied outbreaks like Ebola, Zika and dengue fever.

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S8: There are a lot of really important goals, scientific goals for several surveys. One is to establish that level of antibody prevalence in the population. So how many people have been infected? So that’s one goal. Another is to establish how many cases are we missing? How many infections are we missing? Because we know we’re missing a lot because there hasn’t been enough testing available. And we know that there are people who have very mild illness. So it allows us to really identify the bottom part of the iceberg. We think about diseases, an iceberg where the top are the people who are very severely ill or who die. And the bottom part includes the mild infections and the asymptomatic infections as well. It also allows us to identify who are the groups who seem to be at highest risk of infection, foreseeing particular populations that have much higher rates of antibodies than others. Those are the groups that we’re going to want to target the most and identify why are they being infected or and how can we prevent that?

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S1: So in some ways, antibody tests could give you, I guess, ammunition in sort of responding to a current infection. You could say, oh, look, this population seems to be particularly affected. We can step up our prevention efforts with this group of people.

S8: Right. So antibody tests allow us to look backwards so we can identify the risk factors. We can’t prevent what happened in that particular group because we’re only looking back. But if we can learn something from those results and generalize those to other populations, then we can help prevent what’s going on in other future populations.

S1: In the U.S., some larger efforts to test for antibodies are already underway and some have made headlines in New York. A sampling of 3000 grocery store shoppers suggested that one in five people in New York City had antibodies. Another one in Santa Clara County, California, showed a much higher presence of antibodies than expected. That could mean two things. One, that the disease is less deadly than previously thought, or two, that more people have some degree of immunity because they’ve already had it.

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S8: There have been a lot of questions about whether there’s some huge number of people who have been infected but didn’t know it. And there are people who are hopeful that because we were you know, if we’re missing a big fraction of infections, that maybe there’s some buildup of immunity in the population. It means that we don’t need to worry anymore, that this will slow down the epidemic. I think based on what I’ve seen, it’s roughly, you know, 10 to 20 infections are missed for every case that’s detected. What was striking was some of the Santa Clara results was that they were saying we were it was one out of 50 to 85. They’ve actually since updated their results. And those numbers have come down as they fixed some statistical problems. But in general, they do give us good information about the ballpark. Where are we living roughly?

S1: Well, that’s a question I have. Is there a risk that in publishing studies like these, particularly with limited pools of data, that people feel safer than maybe they should and more ready to return to normal than might be considered wise by someone like you?

S8: I think we all want to return to normal, but there’s a danger in selectively picking out evidence from a study that supports our beliefs. So one way to look at those studies is that the disease is much less severe so that there are a lot of people who are infected who aren’t getting severely ill. And that’s true. We’ve known that there are a big chunk of people who have no symptoms at all. But we’ve known that from the beginning. What the disease still can do is decimate health systems, spread very quickly. And when we talk about big numbers of people being infected, even a relatively rare outcome like death starts to happen very frequently. And so it would be wrong to interpret those results as very comforting when what we know is that we’re still seeing a big top of the iceberg in certain places. We’re seeing a lot of deaths and a lot of hospitalizations.

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S1: Antibody testing gives us a better understanding of how the virus spreads in different communities, but it also plays an important role in what happens next. If researchers can show that a certain percentage of a population has antibodies, it allows them to track our progress toward herd immunity and herd immunity is what it sounds like. It’s the point at which enough of the population is immune to a disease to slow and eventually stop an outbreak. But Natalie says this is an idea that’s normally discussed in the context of a disease with a vaccine like measles.

S8: For measles, for example, we need enough people to be vaccinated to prevent measles from spreading. Measles is highly infectious. So we need very high levels of vaccination in order to prevent new outbreaks. And herd immunity means that even people who are not themselves vaccinated, maybe they’re immunocompromised and can’t get vaccinated, are protected by the herd being immune. So that’s a prevention strategy that’s vaccinating people. That’s a safe strategy to protect people. But in this context, when we talk about natural herd immunity, that means that people are being infected. So it’s not a prevention strategy. It just means that a lot of people have been infected and many of whom have gotten ill. We need threshold’s of herd immunity, something like two thirds, 67 percent, you know, roughly something around there in order to really start to slow, dramatically slow the spread of disease.

S1: When we’re talking about herd immunity, the numbers required to get there seem really big. And yet, is that safe? Does it does that confer on a population some moment where we can all wipe our brows?

S8: So there’s this concept in infectious disease dynamics called overshoot. And the basic idea is that the herd immunity threshold is not where things stop, but it’s where things start to slow down. Epidemics have a certain amount of momentum. And so when enough people are infected, even if 67 percent or whatever the threshold ends up being, even if that many people are immune, the epidemic doesn’t just stop in its tracks because there are still people out there who are highly infectious and then can spread to others.

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S1: All of this leads me to the question of what Sweden is doing with, you know, they’ve got some precautions and rules, but not the kind of water lockdowns we’ve seen in lots of other countries. And I know that the government there would dispute my wording. But is it appropriate to say they’re aiming for some kind of herd immunity?

S9: It’s hard to know exactly what’s going on in Sweden because they’re publicly saying one thing, but then you can also see the people who advising them are thinking about other things.

S1: The country’s chief epidemiologist, for example, has given interviews where he’s talked up the effects of herd immunity.

S9: I mean, on its face with Sweden’s doing, a lot of it is is very smart and they are thinking about sustainable strategies for their economies. But I do worry that they’re not taking the disease seriously enough in other ways. They seem to assume that it’s really quite safe for young people to be infected when I’m not convinced that that’s true. You know, when we see large enough proportions of the population being infected, we are seeing outcomes in young people that are quite severe.

S8: I also wish that Sweden was being more aggressive about actually trying to prevent the spread of disease. And they’re not they don’t seem to be actively pursuing contact tracing, whereas some of their neighboring countries like Norway, are pursuing this quite aggressively. And that’s what’s really helped drive the numbers low. So, you know, when we compare Sweden with its neighboring countries and Scandinavia, we’re seeing much higher rates of death, much higher rates of cases. And I think that’s really because, you know, even though they have some measures in place, like banning large events and, you know, closing universities and things that are going to slow down the rate of infection, it’s not going to really work to push the numbers low because they’re they don’t have a proactive strategy in place to actually prevent infection.

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S1: There are certainly people here in the U.S. asking why we can’t adopt a similar strategy. What do you think of that?

S8: I think they don’t know what it really means. I think they don’t know what it means just in terms of the numbers. The numbers are shocking. Something like 200 million people in the U.S. alone would need to be infected. And I don’t think people understand that a lot of people would fall into the high risk category. I mean, the basic premise is that we let the low risk people get infected and the high risk people hide away for some long period of time. I don’t know how that works, but more people are high risk than they realize. I mean, we start to see increases in severe outcomes even at the age of 45. And a huge fraction of the U.S. population has hypertension, diabetes. I mean, these all put people at risk and other key part of the strategies that somehow you can separate high risk and low risk people. But that’s just not how things work. I mean, young people work at nursing homes. They you know, they have older family members. It’s just all I can think is that if you want to really protect the vulnerable, then you just need to keep numbers low across the board.

S1: I think so much about what feels like a national and global hunger for certainty. Right now, we’re humans. We want answers to things. I think a lot of us are used to science giving us answers. And there is this moment where when confronted with a new disease that is not possible or not possible to the degree that we want. When you look at the clamor about antibody testing or herd immunity or any of these big concepts, I guess I wonder. Do you think about it? As a scientist, do you think about it as a person who probably wants to get out of her house? You know, how do you how do you make sense of our desire for certainty in the face of something that isn’t.

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S9: It’s very, very natural to want certainty, and I think the public is used to science giving the answers at the end. Right. A study is published. We have some answer and then that’s when the public finds out about it. But the reality is science is a process. It’s a very messy process. So scientists are really used to uncertainty. I’m very used to uncertainty, especially because I specialize in emerging infectious diseases where we have to make decisions. We have to figure things out kind of on the fly with very limited, poorly measured data. So what’s happening is that the public is seeing this process that’s usually reserved just for scientists play out in a more public way.

S8: And I think that’s very confusing for the public, but it’s very normal for scientists. So one important thing is for scientists to learn how to effectively communicate with the public in a way that is clear and digestible and conveys the limitations.

S10: And that’s not a skill that they teach you in your P.H. Dame Natalie Deane.

S3: Thank you very much.

S9: Thank you.

S3: As fun, Natalie Deane is an assistant professor of biostatistics at the University of Florida. That’s all for today. What next? TBD is produced by Ethan Brooks and hosted by me, Lizzie O’Leary. And it’s part of the larger What Next family. TBD is also part of Future Tense, a partnership of Slate, Arizona State University and New America. Mary will be back on Monday. Thanks for listening. I’ll talk to you next week.