The Future Of Immune Health Might Be Here

Summary

Podcast Summary: Short Wave – "The Future Of Immune Health Might Be Here"

Host: Emily Kwong (NPR)
Guests: David Ewing Duncan (science writer, “experimental man”), John Tsang (Professor of Immunology, Yale University)
Date: November 12, 2025
Length: ~15 minutes

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Overview

This episode dives into the cutting-edge science of immune health assessment. Host Emily Kwong is joined by journalist David Ewing Duncan and immunology professor John Tsang to discuss the development of a new "immune health metric". The conversation explores how this metric—developed by Tsang and colleagues at Yale—could change the way we understand, measure, and potentially improve our immune health, and what it might mean for the future of medicine.

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Key Discussion Points & Insights

1. Meet the “Experimental Man”

• David Ewing Duncan has spent his career undergoing cutting-edge tests to better understand human health ("I was one of the first humans to have my DNA sequenced for a story for Wired magazine." – David, 00:28).
• Over decades, he has collected 70TB of personal health data, spanning genomics, proteomics, microbiomics, MRI scans, and more (01:01).

2. What Is Immune Health And Why Does It Matter?

• Kwong describes the “immunome”: the layers of genes, proteins, and cells that make up our immune system (01:50).
• There are 1.8 trillion immune cells in our bodies, with many constantly patrolling for threats (02:11).
• Tsang emphasizes that immune health is as—or more—important than biological age and is central to how we recover from illness (01:55, 02:20).

3. Traditional Versus New Approaches to Measuring Immunity

• Traditional Test: The Complete Blood Cell Count (CBC) just measures basic blood cell numbers, giving a vague snapshot of immune status (05:28).
  • "The CBC just tells you there's something going on in your body... Your body is incredibly complicated, and you know there's some infection somewhere, so it doesn't tell you where it is, it doesn't tell you what it is." – David (06:11)
• New Approach: Tsang’s “Immune Health Metric” draws from much deeper analysis, looking at holistic deviations in the immune system (06:38).

4. How the Immune Health Metric Was Developed

• Tsang’s team studied both healthy people and those with rare immune defects to create a comprehensive “map” of the immune system, identifying connections and deviations from health (06:38).
• They also used artificial intelligence to analyze patterns and create a meaningful, comparative score:
  • “We thought, well, now let's represent each person just as a string, long string of numbers. You now have a map that you can place each person on...” – John (07:58)
• This score is not static; it gives a snapshot of immune health at the time of sampling (10:39).

5. Sampling, Data, and the Next Steps

• The limitations of the metric are primarily in data diversity; the Human Immunome Project aims to broaden immune measurement globally with better representation (09:13).
• They are attentive to privacy concerns:
  • “Our mission is to make this openly available... we want to protect the privacy of the participants. So the goal is not to take this data and sell the data to any specific entity or use it to benefit only a specific entity.” – John (10:05)

6. David’s Test Results and What They Mean

• David’s immune health score was 0.35, which, after explanation, placed him with a group about 20 years younger than his actual age (11:05).
• Interestingly, other health indicators for David were not as positive (e.g., kidney issues), raising important questions: Does immune fitness override or reveal more than organ-specific tests? (11:06).
• David highlights that catching low immune scores in otherwise healthy people could help detect illness earlier (11:55).

7. Big Picture: Future of Medicine

• Tsang foresees a world where regular immune health monitoring could inform early intervention and drive highly personalized treatments (12:21).
• Potential for rare diseases: Immune health mapping could help diagnose patients who have defied standard diagnostic approaches (12:21).
• Duncan sums it up as “somewhat revolutionary,” suggesting the immune system’s health may underpin why people react differently to diseases like Covid or allergies (12:55).

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Notable Quotes & Memorable Moments

• On the importance of immune health:

  “It’s probably the most important system in our bodies. It literally decides if we’re going to be able to heal ourselves...”
  — David Ewing Duncan (01:55)

• On the new approach’s holistic nature:

  “We now really have, through John’s work and others, a way to show how the body really is working as a holistic unit. And the immune system is key to that.”
  — David Ewing Duncan (07:34)

• On privacy and global data collection:

  “The goal is not to take this data and sell the data to any specific entity or use it to benefit only a specific entity.”
  — John Tsang (10:05)

• On the potential for early intervention:

  “Spotting a low immune health metric in a seemingly healthy person could make it possible to identify and start treating an illness before symptoms appear, diseases worsen, or tumors grow...”
  — Emily Kwong quoting David’s article (11:55)

• On the paradigm shift in medicine:

  “I don’t use this word ever, you know, because I’m a skeptical health journalist. But, you know, this is somewhat revolutionary...”
  — David Ewing Duncan (12:55)

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Important Timestamps

• 00:28 – David reflects on being “experimental man”
• 01:12–02:20 – The role and scale of the immune system
• 05:28–06:23 – Why CBCs aren’t enough
• 06:38–08:51 – How the immune health metric is developed & AI's role
• 09:13–10:05 – Human Immunome Project and privacy considerations
• 10:39–11:06 – David’s test results and what they reveal
• 11:55–13:32 – Potential of early immune detection and the future impact on medicine

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Conclusion

This episode highlighted both the promise and the complexity of personalized immune health. Through the story of David Ewing Duncan and the pioneering work of John Tsang’s lab, listeners get an accessible, engaging exploration of how immune “scores” might become a standard tool for predicting, diagnosing, and perhaps even preventing disease long before symptoms emerge. The conversation is candid about limitations, ethical considerations, and the real-world impact such science could have—an exciting glimpse into the future of medicine.

Transcript

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[Emily Kwong]

You're listening to Short Wave from NPR. David Ewing Duncan describes himself as the experimental man.

[David Ewing Duncan]

25 years ago, I was one of the first humans to have my DNA sequenced for a story for Wired magazine.

[Emily Kwong]

David is a journalist and a science writer.

[David Ewing Duncan]

And we almost didn't do the story. It seemed a bit gimmicky, but we did it and it really resonated with people. And so I was kind of off and running.

[Emily Kwong]

And he has made a career out of this, out of signing up for tests promising new insights into health and mortality. After sequencing his genome, he later tested his proteome, the proteins circulating in his blood, then his microbiome, his metabolome.

[David Ewing Duncan]

And I've got about, I don't know, at last count, about 70 terabytes of data on myself, which is an extraordinary amount of data. A lot of that is I got a lot of MRI scans. So that that eats up a lot of. A lot of bites.

[Emily Kwong]

It is really a twist on the line in Hamlet, know thyself. Yes, but in all these terabytes of.

[David Ewing Duncan]

Data, maybe 98% was not useful, but the 2%, this man, John Tsang, is largely responsible for.

[Emily Kwong]

John Tsang is a professor of immunology at Yale University, and he and his colleagues have devised a test to measure immune health. They call it the immune health metric. And when David, the experimental man, heard about it, he said, sign me up.

[David Ewing Duncan]

I've had long haul Covid twice. I've had a couple of surgeries, like, what is my immune system health, otherwise.

[Emily Kwong]

Known as the immunum. Made up of many genes and proteins.

[David Ewing Duncan]

It'S probably the most important system in our bodies. It literally decides if we're going to be able to heal ourselves when we get an infection or a disease, its health or lack of health is different than our actual biological age.

[Emily Kwong]

And as John reminded me, there's roughly 1.8 trillion of these little immune cells hanging out in your body right now, seeing what's good.

[John Tsang]

And many of them are residing in different organs and tissues, and many of them also move around your entire body. They patrol and they try to check out different tissues and organs, and then they see what's going on.

[Emily Kwong]

To respond by, say, running up your body temperature to fight a cold, return your system to homeostasis, and to remember those threats for next time.

[John Tsang]

It has to remember, have I seen the flu? Have I seen the COVID or have I seen a lot of inflammatory signals? So now in my next response, I may want to anticipate what's coming in.

[Emily Kwong]

John's test, the immune health metric requires a blood sample. So David gave his blood and after a ton of fancy calculations, got his score. This snapshot of his immune health. He was nervous about how he'd fare and then he got the text from John.

[David Ewing Duncan]

So my score was 0.35.

[Emily Kwong]

And how did you feel about that?

[David Ewing Duncan]

I honestly didn't know what to make of it. You know, it's just a random number. And I had to get a lot of explanation before I really understood what that score meant.

[Emily Kwong]

Today on the show, the future of immune health may be here. Now, can extremely personalized medicine unlock the secrets of how healthy you are and how long you may live? Plus what David's score means. I'm Emily Kwong. You're listening to Shore Wave, the Science podcast from NPR.

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[Emily Kwong]

All right, John and David, I want to start by talking about how doctors have historically assessed people's immune health in the past. Like, how is immune health measured?

[John Tsang]

John they actually don't have a Very good way to summarize. Overall, how's your immune health? All we got. Typically, if your doctor orders it, it's what's called a cbc. It's a complete blood cell count.

[Emily Kwong]

Complete blood cell count. I know the CBC is the Canadian Broadcasting Corporation.

[John Tsang]

That's right. I'm Canadian.

[Emily Kwong]

Oh, nice, nice.

[John Tsang]

So the complete blood count, it provides you with the absolute count and frequency of certain cells in your blood. That's nothing very specific. You can basically tell by just looking at those numbers. But how to link the CBC to the health of your immune system and how to link the CBC to other aspects of your health, it's still an open problem.

[Emily Kwong]

David, why is that test just simply counting not enough?

[David Ewing Duncan]

Well, the CBC just tells you there's something going on in your body. I mean, you know, your body is incredibly complicated, and you know there's some infection somewhere, so it doesn't tell you where it is, it doesn't tell you what it is.

[Emily Kwong]

And so the complete blood count, the cbc, that has been the standard, more or less, for assessing people's immune health for decades. But now, John, your lab has developed a new test, the Immune Health Metric. How did you make this test?

[John Tsang]

In our case, we started with both clinically healthy people, so no obvious disease, and then also various groups of people suffering from various genetic defects. Each one of these person is like, suffering from a natural perturbation, or it's like a hammer knocking stuff around right in their system. If we look at enough of these peoples where the hammer is knocking on different points in the immune system, we can build a map on how different parts of the immune system, it's connected to each other, number one. Right. And number two, we can start to ask the question, despite that these diseases originated from different parts of the immune system being perturbed, are there common deviations? And we call that common deviation from health.

[Emily Kwong]

It's like knowing the immune system on a far deeper holistic level than merely like it exists.

[John Tsang]

Correct?

[Sponsor/Advertisement Voice]

Yeah.

[David Ewing Duncan]

Right now, medicine is still practiced organ by organ, system by system, and we've been tending towards this idea that actually we do have a system that's connected together. And we now really have, through John's work and others, a way to show how the body really is working as a holistic unit. And the immune system is key to that.

[Emily Kwong]

John, you also used AI to develop the test. How so?

[John Tsang]

Where the AI came in is very intriguing. We thought, well, now let's represent each person just as a string, long string of numbers. You now have a map that you can place each person on that map. Right. If you take the very first dimension that explains the most amount of differences across all of these people that we have looked at correlated almost perfectly with this probability of someone being healthier. AI was rediscovering, in a way, our probability of being healthy. Axes. And that's super intriguing because it suggests that that's the most fundamental wavelength, in a way, in the system. And once the AI is done, we can go back and ask, what did you use in order to compute this probability? That's how we figure out how some of the underlying parameters are contributing.

[Emily Kwong]

Gotcha. What are the limitations of that method? Just because everyone's bodies are so different and you have sampled hundreds of people, but not millions or billions of people on the planet, what additional data do you wish you had to make your predictive models better?

[John Tsang]

Actually, that's where we're moving next right now. It's called the Human Immunome Project. The idea is we want to measure the entire world's immune system to increase representation of individuals with very different genetic backgrounds, very different exposure histories, facing very different kinds of stresses, and so on. So that would help us to train these models to better represent all of the individuals on earth in terms of.

[Emily Kwong]

Their immune system in the pursuit of gathering more data. And I read in David's article, the plan is to send immune monitoring kits all over the world. Are there going to be any kinds of, like, data privacy safeguards? Because we've seen so many health efforts in which people's data is then, like, sold to companies. So is that part of your plan at all with the Human Immunome Project?

[John Tsang]

No, that's. That's not part of the plan at all. Our mission is to make this openly available for researchers and anyone around the whole world. And second, we will be working with all the local scientists and jurisdictions about data privacy and everything. And in the sense that, of course, we want to protect the privacy of the participants. So the goal is not to take this data and sell the data to any specific entity or use it to benefit only a specific entity.

[Emily Kwong]

Okay, I want to go back to David's score, your immune health metric. Now, this was the score that was from the time of sampling. It's not like your forever score. It was 0.35. And you were told, what about it?

[David Ewing Duncan]

Well, I was placed with a group of people about 20 years younger than me, meaning that my immune system seems to be about 20 years younger than my actual biological age.

[Emily Kwong]

Nice.

[David Ewing Duncan]

And the interesting thing about that is I do have Other tests I'm taking right now that are telling me in various ways I am not that healthy, say in my kidneys and a couple of other places. But the question is, does the health of my immune system override that? So I'm on a quest here to find out what does all this mean for one person. And it's not really that it's all about me. Although I'm interested in my own results. It's really, I'm being able to play the role of the guinea pig, the human guinea pig here. And these are all questions that I think will be teased out over the next few years. And this is the first time in all of my testing for 25 years that I've actually had a study that begins to tell me what's going on in a holistic way in my underlying health.

[Emily Kwong]

Yeah, you write spotting a low immune health metric in a seemingly healthy person could make it possible to identify and start treating an illness before symptoms appear, diseases worsen, or tumors grow and metastasize. And you write about a world in which maybe John's test tests like it, the numbers could be available on like an app if people are regularly sampling. I mean, what impact could this have on medicine?

[John Tsang]

Yeah. Imagine a world where you could monitor how, how things are going in your body and when there are signs that your body's going in the wrong direction, you can start to ask the question, can I modulate my immune system in particular? On the other end of the spectrum, there are rare disease patients. After years of bouncing around different medical specialties, they're undiagnosed. Still undiagnosed. We can now pinpoint what's going on. What does the immune system sense? And now can we move this person back to health?

[David Ewing Duncan]

One of the major findings of John's work and others is a kind of paradigm shift. And it's really, I mean I don't use this word ever, you know, because I'm a skeptical health journalists. But, you know, this is somewhat revolutionary that we're moving into this phase where I think it will shift medicine around. You know, why do some people get Covid. Why do some people not? Why do some people get allergies? Why do some people not? That's clearly has to do with your immune system and probably your immune system may be more important than the actual severity of these threats.

[Emily Kwong]

To learn more about the Human Immunome Project or to read David's full article about this in MIT Technology Review, check out our show notes. John Tsang and David Ewing Duncan, thank you so much for coming on Short Wave.

[David Ewing Duncan]

Thank you.

[John Tsang]

Thank you very much.

[Emily Kwong]

This episode was Produced by Burleigh McCoy. It was edited by our showrunner, Rebecca Ramirez, and fact checked by Tyler Jones. Robert Rodriguez was the audio engineer. I'm Emily Kwong. Thank you for listening to short wave from NPR.

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[Emily Kwong]

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