The Air is Alive - Going Air-Borne with Carl Zimmer

Carl Zimmer, science journalist and author, discusses his fifteenth book, Air-Borne: The Hidden History of the Life We Breathe. Zimmer’s career includes two decades of science reporting for the New York Times and early editorial work at Discover magazine.
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Airborne documents the science of aerobiology and the historical refusal by public health institutions to recognize airborne disease transmission. The conversation highlights the neglected epidemiological research of William and Mildred Wells, the fragmented nature of atmospheric sciences, and how the complex realities of scientific validation collide with public policy during global health crises.

Key Topics:

• Aerobiology and the microscopic life thriving in the atmosphere.  
• How COVID-19 exposed century-old dogma against airborne transmission.  
• William and Mildred Wells' pioneering use of UV light to disinfect air.  
• Book writing craft, archival research, and the value of physical books.  
• The dangers of scientific silos in Aerobiology and epidemiology.  
• Rapid-fire COVID-19 facts, virus origins, and political threats to science.  
• The global tuberculosis crisis and the consequences of defunding health programs.  

Carl's Links:

• CarlZimmer.com
• The Future of Ageing Podcast
• @carlzimmer.com 

Book Science:

• Website: https://www.trippcollins.com/podcast.html
• Show notes & transcripts: https://www.trippcollins.com/show-notes
• Check out the Book Science Book Shop on BookShop.org
• Instagram: @booksciencepodcast

Transcript

Tripp Collins 0:00

Welcome back to Book Science. This is Tripp Collins. Thank you for tuning in. Today, I am sharing a conversation with the one and only Carl Zimmer. Carl Zimmer is the author of 15 science books. He teaches science communication at Yale University, but he's probably best known for his award-winning science reporting on biology, evolution, and heredity. He's a regular columnist for The New York Times and a former senior editor at Discover Magazine. Alongside sharing the 2021 Pulitzer Prize for his contributions to The Times' COVID-19 coverage, he holds the unique distinction of having an asteroid, a strain of bacteria, and a species of tapeworm named in his honor. Well, how cool is that? Today we are talking about his latest book, Airborne, and I hope you enjoy this conversation Today I am joined by Carl Zimmer, author of no less than 15 science books most recently Airborne, the Hidden History of the Life We Breathe, airborne at, the highest level is sort of a history of the little known science of Aerobiology, which is a study of life that exists in the atmosphere, including the air we breathe. airborne covers a lot of ground, including life found high in the atmosphere, disease transmission, bio warfare. but Carl, what would you say this book is all about?

Carl Zimmer 1:55

Yeah, I think that people will be surprised to discover that the air is alive. that, you know, the atmosphere is a habitat. and it's not just The bird you might see flying overhead or a dragonfly buzzing by you, but you know, going all the way up to the stratosphere. there is an immense amount of life, much of it, invisible to the naked eye, but it's really important to the natural world, here on land and in the ocean, and also to our health.

Tripp Collins 2:29

would you say, this area of study, is not well known to most people. but it's become something we've, renewed interest in because of its application to disease transmission. and in particular during COVID, I think I read that, this book was initiated through your coverage of COVID. I was curious about, the inception of the book, but also can you comment a little bit about, your journalism and how it's in conversation with your books?

Carl Zimmer 2:56

Uh, for a long time they've been in conversation with each other. I actually started in science journalism working at a magazine called Discover. And, there I was really, very young learning the ropes, and, figuring out how it is that you write for a broad audience about science. And I started to write articles, then features, and after a while with these features, I would get really frustrated because even though I might have 4,000 or 5,000 words to write about some big subject. I would look at, all of the papers and all the interesting stuff that I had amassed that, I didn't have room for in the article. so a friend of mine who was actually becoming a book publisher at that time and was wanting to publish science books, said, well, why don't you write a book? And, he invited me to, think about what I might write. And, um, I thought about some of the most interesting things I'd been working on at Discover. And I was really interested in evolution and big transformations, like, how our fish ancestors came on land. And so that became my first book, which was at the Water's Edge. Um. Since then, I have gone on to write for a number of different places, mostly, in recent years for the New York Times. it's been about 20 years that I've been contributing there and became a columnist. from time to time as I'm learning new things about science and discovering some of the interesting history, an idea for a book will, kind of present itself to me. I don't actively look for, ideas for books because, my view is like, if you're gonna spend a couple years working on something, you know, you, it really has to take hold of you. So I sort of, let ideas come to me and if they really take hold, then maybe I'll go forward and think about a book. And so. In the case of Airborne, the seed for it, was planted during the, early months of the pandemic. In 2020 when I was working with colleagues at the New York Times, we were writing as fast as we could reporting on this new disease and reporting on scientists, trying to make sense of COVID. And there was a lot that didn't make sense We thought we knew that turned out to be wrong and so on. And, one of the most fundamental questions was how does it spread? and so I, like a lot of people was wiping down groceries, early in the pandemic because, It was what we were recommended to do because it was thought that the virus was spreading on surfaces, contaminated surfaces. so if you, you know, if you washed your hands and you kept surfaces clean, and if, you know, keep a few feet from anybody who showed symptoms so they didn't like sneeze in your face, you'd be okay. And that turned out to be wrong in the sense that COVID is airborne, that we release the virus into the air and it can spread, like, smoke so in a poorly ventilated indoor space, you can inhale it quite far away in under the right conditions. That just really stuck with me. Like, why was there such a big fight about how COVID spreads? and that got me into understanding all the work on airborne transmission and how public health experts have actually been downplaying and discounting the possibility of airborne transmission for a century.

Tripp Collins 6:42

Mm-hmm.

Carl Zimmer 6:43

and that kind of, from there, I kind of widened out to sort of think about, well, you know, what's in the air and how do we think, what's been our history of discovering what's in the air? And before you know it, I was working on a book.

Tripp Collins 6:56

And so do you commit to a book before you, before you begin serious research? or do you just follow your interests and then, decide at some point? Well, you know, I think there's enough here, enough content, enough fuel for a book. I.

Carl Zimmer 7:11

I will start doing preliminary research for a book, mainly first of all to satisfy myself that it would be a good idea for a book. In other words, there's stuff out there that I can write about. There are resources out there that I can use, and that it's not a book that basically has been written once or many times before.

Tripp Collins 7:40

Mm-hmm.

Carl Zimmer 7:41

I want to try to, I wanna do my best to try to contribute something new. So, I'll do that work, I'll talk with, sources and start to build up my research. And then, for me the next step is to then write a proposal. So I'll work up a proposal, show it to my agent, and then if we agree that it's ready to be shared, then he sends it out. either to the editor I've been working with for a previous book, or in some cases going out to other editors. And then we see what the interest is and, once I've got a contract, then I dive in.

Tripp Collins 8:21

when you're talking about, the importance of bringing out new information, I found this book so full of surprising characters and facts and stories and it made me wonder, considering how much writing and research you've done over your career, did the process of uncovering this book feel special in some way? Did it feel different?

Carl Zimmer 8:39

It was different in the sense that, it was, I was working a lot more like a historian than I have in other books in the sense that, I mean, I'm not trained as historian, you know, I don't have a PhD in history of science or anything like that. and I really admire, you know, professional historians, especially of science and medicine. I've depended on their work a lot, but. This was a case actually where, those historians really hadn't touched this area, which really surprised me. for example, during the COVID pandemic, I remember talking to, an infectious diseases expert named Donald Milton at the University of Maryland, who was somebody who had done a lot of work on airborne transmission, and he had really been pushing the World Health Organization to recognize that COVID could be airborne and to really take that possibility seriously. And he turned out to be right. And I was asking him like, well, what, you know, I'm trying to understand this conflict that you've had. you know, where does this come from? And he said, well, you need to. Learn about William and Mildred Wells, and I said, I have no idea who they are. And so they are, they figure prominently in the book, they were, in the 1930s and forties real, you know, incredible pioneers in particularly in looking at, you know, the life in the air in terms of how it makes us sick, how it can transmit diseases. at the time, I was like, okay, well I'll go read a biography of them. There's no biography of them. Just none, never been written. at best there might be like a paragraph here or there. I was like, who are these people? You know? And so, you know, I started to, do research, you know, do a lot of research in newspapers because at the time a lot of their work was being covered in newspapers. they started piecing things together. And then I wondered, well, you know. Maybe there's archival material. And and it turned out that the Rockefeller Archive Center had maybe, I wanna say 30 boxes maybe of material. I don't know who's looked at that before, but it was like letters and unpublished memos and manuscripts and reports and whatnot. All sorts of things. which really, you know, just opened up, their lives. this husband and wife team who really, it's quite tragic 'cause they were trying to get the word out about airborne disease and they lost, they failed. and you kind of discover the struggles they went through Frustrations and real, and how it kind of ripped their marriage apart. it's a lot, you know? and so I was in these situations where I was working with archival material on them and some other people and really trying to reconstruct people's lives. and that was a really, uh, that was a really interesting, challenge.

Tripp Collins 11:39

Yeah, I definitely wanna return to, the Wells. there's, like you said, there's story features prominently and there's so many, you know, interesting aspects of their story To dive into, but, before we get there, I want to just ask a couple more craft questions and then we'll get into more like content. so what does a writing day look like for you? Or do you differentiate writing days versus other type of days?

Carl Zimmer 12:03

I don't necessarily sit down and say today's a writing day. it's more just looking at my schedule and saying, all right, what have I got to do? Yesterday was a writing day for me because I had to file a column and I had to get it in and, and the story, you know, I had to get it in, in time to be edited. And so boom, you know, it's gotta get done. the deadlines for books are run at a different timescale. but you know, you sign, if you sign a contract and you say, I'm gonna be turning this in in a year and a half, well, you know, sounds like a long time, but it's not. so I will, you know, start to kind of map out, well, what's that year and a half gonna look like? what time am I gonna be spending doing research? And then when am I gonna really start drafting? There, there are some days where, I don't write much at all because I'm just doing research and I still don't feel ready to write. I don't know what the story is yet. then there are days where I'll just write, for, I don't know, 12 or 15 hours, I'll just kind of lose track just because like, everything's together, everything's ready, and, it's all coming out just like I want it and I kind of don't wanna break away and, lose that flow. I wouldn't say there's a typical writing day for me. I know there are lots of people who are very orderly in how they write and they

Tripp Collins 13:24

Strict routines.

Carl Zimmer 13:26

Yeah. And if that works for them, That's great. But that's not my style.

Tripp Collins 13:30

Yeah. you have a quote in, the National Association of Science Writers Column. It says, I ended up with my own monster when I finished my first draft of Airborne, and then I spent months killing my darlings. Helps you think of your draft as a huge chunk of marble, which you can chisel down into a sculpture. and you have to schedule a lot of time for the sculpting. yeah, I found that, really interesting. can you expand on that process of removing the text to reveal the book? and, you know, just for fun, is there anything that you had to cut that you'd like to mention here? I,

Carl Zimmer 14:01

I think everything, that was in that first monster manuscript is in this much more slim down one, but it's just, it's everything. Everything's been, you know, I just tried to sort of distill things better and to kind of just, you know, sometimes there were like, you know, small characters who I would end up turning into big characters and then I'd have to say like, no, this is actually a small character. Like one example is Charles Lindbergh. Charles Lindbergh has this. Crucial, but, brief, contact with this whole science of Aerobiology. one of the pioneers of Aerobiology reached out to him in 1933 when he and his wife Anne, were going to take a flight across the Atlantic, going over Greenland to Europe and asked him basically to do some research to see if he could catch stuff in the air high over, the North Atlantic. Um, I mean, nobody had ever done anything like this before, so no one knew. and he did it. he actually helped design the instrument that he ended up, using. And, it was a real sensation when the news came out. it really got people thinking about life in the air and how high can life go? What are the limits of life? Once, you know, I wanted to introduce Lindbergh as like a person, as a real, you know, three-dimensional character rather than, some cardboard cutout that we've all vaguely heard of. So, you know, I, I knew some about Lindbergh before, but I was like, let me dig in and get to know him, and oh my gosh, like, whoa, like Lindbergh is just a, you know, it's no surprise that there have been tons of big biographies written about him and that everybody sort of struggles to make sense of him. He is a really hard to understand person with, you know, incredible acts of heroism. And then also you, eugenicist you know, very, very, you know, Nazi adjacent and just all these things, and more. And so somehow I tried to sort of like, you know. Veer off and talk about all of that, in, in a lot of detail just because all the details I found so interesting. And then, you know, I really needed people like my editor and my wife who's like an, an amazing editor herself and, and other people to be like, okay, enough with the Lindbergh, like we, we did, we don't need to know all this about Lindbergh. So Lindbergh's there, but you know, he takes up just a few pages instead of more.

Tripp Collins 16:37

Yeah, I didn't know a lot about Lindbergh prior to reading your book. I mean, I just vaguely knew about his pioneering, work as a pilot, you know, early pilot, going more like an adventurer. and I knew a little bit, about the eugenic stuff, but yeah, you kind of brought him to life. I can tell that there was a lot behind the amount that you wrote, a lot of research 'cause you really did bring his character to life You know, not just a life of adventure, but a life of tragedy. He, had his son kidnapped while they were away and tragically died. and it's clear how it affected, Ms. Lindbergh, I can't, I'm sorry, I can't recall her name, but he seems to Ann Lindbergh. Yeah. And he seems to not have reacted so much, or, you know, like they're just like strange parts of his personality, that definitely come out. yeah. and so I just wanted to mention briefly that, the scientist that he was working with was Myers, right? And so Myers was interested in the atmosphere and the wells were sort of more down to earth interested in disease transmission. And you do a great job of talking about that schism and Aerobiology. There was sort of the people interested in, in the air and, and sort of the people interested in diseases. And they didn't really, that, that schism existed for a long time. they had a very hard time, translating their sciences for each other and, and, and making progress in that way. do you think, does that schism still exist today? I, I wasn't sure. has that been resolved in some way?

Carl Zimmer 17:57

in Aerobiology, I would say, Yes, it is in the sense that, you know, the people who study life in the air, tend to kind of go off in their own directions. So there are a lot of people who study pollen. I mean, pollen is really important. It's important for us in terms of allergies. and so, you know, now we can actually have pollen forecasts and we can understand, how our allergies are going to be as the climate changes, the turns out they're gonna get worse. pollen is really important for understanding, the distribution of plants and their success. But they, you know, if you talk to people who study pollen, it's as if the atmosphere only contains pollen. And then there are other people who study fungi. fungi are actually specialized in sending up their spores into the air and spreading incredible distances. And, fungi can just cross oceans and so on. And you talk to them and it's like, the atmosphere only contains fungi and ornithologists only think about birds. And so, there are actually efforts now to kind of think of the aerial biome as a system, as a full system, global, a planet wide one. people are asking these big questions like, what is the flux every year of cells? Going into the atmosphere from the ocean and from land and so on, like those numbers are still only just starting to get estimated. but Aerobiology is slowly coming together. But yeah, it, it, I mean that general sort of problem with people kind of being in different silos is definitely a problem. It was one of the reasons why it was so hard for people to recognize that COVID was airborne.

Tripp Collins 19:46

Mm-hmm.

Carl Zimmer 19:47

the people who were really making the call for that were often experts in air pollution or atmosphere chemistry. And the people who were insisting that COVID is not airborne, they were epidemiologists or infectious disease experts who didn't have the expertise to understand the physics of how viruses can spread through the air.

Tripp Collins 20:11

in addition to, a monster of a first draft, the back material is a separate monster. on your website you have 129 page PDF with, citations, references, and all their cousins. at first I was really impressed with this Carl, but after going through it line by line, I double check the source material and I found three errors. So, um, you know, it's not, um, joking of course, but, uh, can you, can you just talk about maybe, this level of referencing, is it standard practice or is this more, because this was more of a, turn towards a history of science, were you trying to, follow their standards or is this something you've developed for yourself over the years?

Carl Zimmer 20:50

when I started at Discover Magazine, one of my first jobs there was as a fact checker. And the job of fact checker is to take an article and to make sure that every single thing in there is accurate. And it's a responsibility of writers to provide checking material. They have to annotate their, manuscripts, say where they got all their information. You know, and provide the information for how to check this stuff. I've still got a fact checker lurking around inside me. And, I had my book fact checked, so I had some, young assistants who, helped out and, it was up to me to tell them where I got everything. So I would just footnote everything. I mean, I quote in order to, bring a lot of characters into this story. You know, I wanted to use their voices. So I was quoting lots of people. Um, and then in order to, when I was describing where people were, were doing things, I wanted to, make it clear, like where, what was my authority to say that? And this was especially important given that I was not just writing a chapter in Charles Darwin and I was getting all of it from some biography, you know, and like, that's it, I was getting it, all the, just lots and lots of sources, letters and memos and documents and, and so on. It all had to be cite, you know, connected to archives and so on. And so I felt a responsibility to just make sure that that was all, backed up. when I turned in my first manuscript, I just sent the whole kit and caboodle of the end matter in with this huge manuscript, and my editor was like, oh, please, could we, we can't, this is too much. And I said, I get it. So what we decided was that I would just, post that big director's cut of the full sources on my website in the book, I source all the quotes and then I have sort of selected references in addition to that. it's, which is still a lot, but it's a lot less than if it had just been the raw form. But, you know, it's tough. there's a lot of pressure on writers, to really, skimp on that end matter. And I think that's unfortunate because the whole point of writing books is to write something that's really gonna last hopefully, in, into the future. And, you want people who wanna dig in deeper for themselves to know where to go. And, um, so, you know, there's no way around it. you need footnotes.

Tripp Collins 23:26

Yeah. And just as a technical matter, you're a fact checker. Was that something that the publisher provided for you, or is that something you had to spring for on your own?

Carl Zimmer 23:36

in that case, yeah, that was bringing on my own, but I was fortunate to also have a fellowship from the Sloan Foundation, which supports, people who are writing books about science. So, part of the reason I said that I would like to have a fellowship is because I wanted to make sure that this book was carefully checked.

Tripp Collins 23:57

Yeah, definitely. and I wanna return to something you, part of your answer was about, you know, the power of a book or maybe the longevity of a book. And there are so many ways to communicate science, and of course you have a column in the New York Times, but, how do you see the power, of a book? Like why is it important that we're still creating books in this day and age?

Carl Zimmer 24:18

I'm relieved that, you can still write books in this day and age. I wasn't entirely sure. I would say maybe, I don't know, maybe 10 or 15 years ago, I was really wondering, how much longer, this is gonna be a thing because, there were all these different kinds of, uh, you know, ways of sharing information, whether it was eBooks, podcasts, social media, so on, so forth. You know, I did start to feel like books might be kind of an old fashioned thing on their way out. and yet, the book industry has thrived. it's been steady. people still buy a lot of books and that's a relief. and I've wondered why that's the case. I think about it sometimes when I go to give a talk and I have a book signing afterwards, and, most people are buying, my news book and I'm signing them. But then somebody will be in line and they will hand me a book that I wrote 10, 15, 20 years ago. And I'll be like, oh, wow. they bought that book and they read it. there was, this sort of. Communion between the writer and the reader that can last for days or weeks and leaves an impression on them. So much. So, that they put that book on the shelf and they keep it there. it's like part of their home and then when I'm in town, they're like, oh, I'm gonna pull this book off the shelf and I'm gonna go get him to sign it because it means something to me. and there's nothing I think that has quite replaced that, at least not yet.

Tripp Collins 25:53

Uh, let's dive a little deeper into a few topics in the book. maybe a good place to start is with some medical history. So what were the major paradigms in the science of disease transmission?

Carl Zimmer 26:09

If you go back, say to ancient. Greece. one very important, concept was of Miasmas. and now miasmas were a sort of a, you could almost think of it like a curse on the air. that somehow the air became corrupted. Hippocrates and other Greek thinkers started to think about, well, what kind of natural conditions might cause the air to be disturbed? thinking less about, the gods smiting you with, something that destroys your crops or spreads a plague, to instead say like, well, maybe it has to do with the heat or the humidity in the air, or things that are rotting on the ground or what have you. But in any case, miasma would float. And it would, it would move along and, if you happen to be in its path and you inhaled it, then you would get sick. And different diseases were believed to be caused by different miasma. So, this is very different than thinking about a communicable disease. In other words, a disease where there's, some living pathogen that is going from one person to the next to the next and causing sickness along the way. and to us it's a really weird idea, and yet it had a lot of explanatory power and so much so that in one form or another, it endured for over 2000 years, you know, into the late 18 hundreds. There were people who were insisting that a disease like. Cholera or yellow fever, was caused by these disturbances in the air. by, you know, some people were still calling them miasmas.

Tripp Collins 28:02

and there were, in the case of cholera, they were partly right. in terms of the way that the disease spreads. So cholera is like the, maybe the canonical example of a disease that spread is an airborne disease that, that is spread by the air. and so much like they thought, go ahead.

Carl Zimmer 28:20

cholera is cholera's waterborne,

Tripp Collins 28:21

Oh, sorry. Colla, I, I'm thinking of tuberculosis.

Carl Zimmer 28:23

tuberculosis. Yeah. So tuber. Yeah. And tuber. You know, the funny thing about tuberculosis is that not fun. I mean, I, I don't think there's anything funny about tuberculosis, but the ironic thing about tuberculosis is that actually, one of the really, Influential ideas about tuberculosis up through the, 19th century was that it was actually a hereditary disease. That there was, you sort of inherited a sort of, kind of a weak temperament from your ancestors that made you prone to develop, this damage to your lungs under, you know, conditions of stress. and indeed, as you say, the tuberculosis is indeed airborne. but it's a, really fundamental distinction that, actually was hard for people to grasp, which, and, and actually led to sort of a neglective airborne disease and the differences that, you know, miasma, it was the air itself. That was causing these diseases. whereas it turns out with something like tuberculosis, it's an infectious disease just like cholera and yellow fever and so on. And which means that there's a pathogen that is causing it. Now, you know, yellow fever is actually spread in a mosquito, it's a virus, and cholera is bacteria that's in contaminated water, contaminated by diarrhea. tuberculosis is caused by another kind of bacteria and it's in the lungs. And people exhale tiny droplets, that inside of which are, are these bacteria and then they can float through the air. so it's very, it's so, you know, when people talk about tuberculosis being airborne, it's not a miasma. But, in fact when people like William and Mildred Wells started to, to, Champion this idea of airborne transmission. you know, they literally had to write down, we are not talking about miasmas.

Tripp Collins 30:26

Yeah.

Carl Zimmer 30:26

Don't mistake us for miasmatists. That's not what we're saying. so they

Tripp Collins 30:31

because it went outta fashion at some point and you, yeah. And to refer to that would give yourself away as unscientific at some point, right? Yeah,

Carl Zimmer 30:39

so, you know, in the 19th century, miasmas were, it's what all the experts said, that was the expert opinion. and then the germ theory of disease. Starts to get the upper hand. And all these diseases that were believed to be in the air are turning out to be not in the air. They're in mosquitoes like malaria and yellow fever. They're in the water, you know, cholera, typhoid, they're in, contaminated food. Some are spread by sex. some are just spread through contact and, you know, drop just droplets that people get on their hands and then they contaminate surfaces and so on. In any case, all these things are getting pulled outta the air. And so, you have public health experts in the early 19 hundreds saying people should be relieved that, the air is no longer this terrifying source of disease. We can relax. You know, our forebearers we're tormented for thousands of years by the idea of my asthmas. And guess what? It's not real. but what happens is that you have the pendulum just swinging way over to, the other side. So that people, believed that, you could get sick from contaminated water. True. You could get sick from contaminated food. Also true. But there really wasn't any idea that you could get sick with an infectious disease from contaminated air. And that became a dogma.

Tripp Collins 32:05

Yeah. And part of it was, the idea of hygiene or sanitation. And, uh, you could clean surfaces, you could purify water, but they really, there wasn't an idea of hygiene for the air at that point. So I think maybe that was part of why they struggled to imagine that air, was part of the issue.

Carl Zimmer 32:25

I would say that people just didn't think that you needed to worry about hygiene for the air because the air was not something to worry about. Now, when Mildred and William Wells. And other early pioneers started to say, oh, wait a minute, we actually think that maybe things like tuberculosis and influenza and measles and so on are actually airborne. Then they were faced with that question like, uhoh, well what do we do, you know, with clean water? Like, what do you do for clean water? Well, there were, you know, it was gonna take a lot of work, but they knew that, the world had just gone through a big revolution with water, for example. Like, in the 18 hundreds, plenty of cities would just get their drinking water supplies from nearby rivers or what have you, literally, like where they were dumping in their sewage, And so there was a huge effort to provide. Clean drinking water by building huge facilities to clean it, with giant sand beds for filtration or, looking at what kind of chemicals you could put into water to kill any bacteria that we're surviving in there. It was a huge public works Effort. And now we, take it for granted in many places in the world, like, oh, like, you know, you don't expect to get cholera if you, go to a water fountain and drink some water. And if I do like someone in the government is really messed up. Well, William and Mildred Wells, were like, okay, what will we do for the air? Like, how do we do that? And they, developed some ideas like ultraviolet light as ways to disinfect the air.

Tripp Collins 34:04

Yeah. In fact, I think, was it Mildred? that was sort of the pioneer of doing the experiments with the lights. She was placing them in schools. she really did a lot of pioneering work. even separate from, William. She had her own expertise, which it sounds like it wasn't well appreciated until you brought it out in the book.

Carl Zimmer 34:23

William Wells certainly had sunk into obscurity, but. Mildred Wells sank even further. And I think a lot of that was because she was a woman. she was a woman in science in, the mid 19 hundreds. And so, she was dealing with, a lot of, unspoken attitudes about what, women were capable of, uh, or not. in terms of scientific achievement. And then also all the burdens of the home. We're on her. she and William had a son who had, suffered from schizophrenia, and stayed at home basically until his parents died. and then had to be institutionalized. And so, it was up to her to make sure that he was okay. So, yeah, so I, you know, when I was looking around for pictures of the wells, it was like I found a few William Wells. I only found one of Mildred Wells. It was her yearbook picture in college. That's it. That's the only picture that I've been able to find. So that kind of gives you a sense of how much obscurity she had fallen into. And yet, you know, it's really, I'm happy to do my part to make people more aware of her because, a lot of. This was really a two person operation. A lot of the key ideas about how airborne infection work she came up with. And then when William discovered that ultraviolet light was very effective at disinfecting the air, then she really took the lead in trying to actually, like, say like, okay, let's put this into practice. so they got their lamps installed in two schools in Philadelphia. And then she was doing massive amounts of epidemiology, looking at medical records, trying to figure out are the kids in the classrooms with the ultra father lamps less prone to diseases than the other kids? And they just happened to install these lights right before a massive measles epidemic in Philadelphia in 1940, which demonstrated very clearly that. Kids in these classrooms with ultra fired lights were 10 times less likely to get measles than unprotected kids. So it was perhaps the first and perhaps the best demonstration that you can protect people from an airborne disease like measles. And then she did go on to do her own very ambitious studies, including one experiment where she basically tried to put UV in an entire town in New York state. because she felt that, just protecting kids in schools wasn't enough. you just wanted to have safe air everywhere. that experiment, it had some good results, but they were mixed and it was a really big undertaking to do that. no one really followed up on it, which was, really unfortunate.

Tripp Collins 37:09

and it was also pretty clear to me that he, as energetic and as, maybe ingenious as, William Wells was. well, they were both very difficult people. But, he in particular couldn't really get much done without her. I mean, reading about him trying to write his book was like the most exasperating thing. I wanted to reach back through time and shake that man. but that story like rhymed with, I think with the broader struggle to effectively communicate to the public about infectious disease transmission, which is another big story in your book. And that, that all felt very intentional. at some point I found it striking, and I mean this as a compliment, is that parts of airborne were like very unsatisfying. Like I kept wanting or expecting a very clean resolution, a definite answer. I maybe it for it to turn into like a science explainer and neatly tie it all up, but you don't do that. you carry the uncertainty all the way through. And I think it relates to questions about the reality of science and, were you trying to kind of show readers the reality of how science often works? especially when it collides with public policy.

Carl Zimmer 38:12

I think that, there are a lot of, people who have an unrealistic idea of how science works. they think that it's pretty simple. you know, people do some sort of experiment and then they get an answer, and then that's settled and then you move on. that's not how science works today. and it's certainly not how it's worked over its history. science is much richer and messier than that. it's much more human. and so I really try to take the science on its own terms. that's not to say that Science tells us nothing. Or that there's no reality that's not true. And you know, certainly, you know, yellow fever is not caused by miasma. Yellow fever is caused by a particular virus, and that's carried by a particular species of mosquito. Like that's, we've learned that. but the process of getting there was very messy. and the process of trying to, you know, it's really interesting in particular about airborne disease. You know, what does it take scientifically? To make a compelling case that something is spread through the air as opposed to by some other route. and it's actually really hard. And that was part of the problem that people like William and Mildred Wells were dealing with was that, everybody had these different standards for what was compelling evidence. And so they would do these, studies, you know, they would do studies with animals or they would do these studies in schools. And then, you know, you can just see, all these experts, you know, very, very intelligent people, you know, colleagues and friends even of the wells. It's be like, well, I don't think, uh, that's not good enough for me. and you know, people say like, oh, well it looks like, you know, airborne infection is not turning out to, to be a thing. and that's the reality. And, it becomes particularly frustrating when you think about COVID, which, is where the book heads, over the course of generations because, if we really sorted this out and we had kind of had a clear idea, and agreed upon understanding of the dangers of airborne infection, then in those first months of the COVID Pandemic we would've responded, quite differently. And, a lot of people might still be alive, honestly.

Tripp Collins 40:31

And from what I gathered from your book, the public messaging was somehow separate from the scientific understanding, and in a lot of cases, the public messaging was either playing catch up to what the scientists understood, or they were downplaying. I'm thinking in particular of the, world Health Organization and their reluctance to. make a statement about the airborne nature of disease. what was behind that? why not just admit that they were uncertain about how it was transmitted, at the very least? why did they keep, seemingly double down on, fomite transmission, which is, uh, droplet transmission, you know, sneezes, coughs, the six foot and all that.

Carl Zimmer 41:14

I think that the people at the World Health Organization and the Center for Disease Control and other agencies, Based on my research, my hypothesis would be that they had all gone to medical school or to, graduate school in epidemiology or these other, uh, sciences. And they were taught that airborne transmission was actually quite rare. That, they would be taught, all sorts of things like, um, you know, only droplets smaller than five microns, can spread airborne disease because only droplets smaller than five microns can float, which by the way in terms of basic physics is just totally not true. but in any case, everyone just sort of like took the stuff on and There wasn't, unfortunately, there wasn't a sort of correcting mechanism to get people to see that these, were incorrect. And so that was the, basis on which then they were, responding to COVID, you know, let's treat it basically like influenza in the sense, like, let's just, you know, we'll just tell people to keep six feet away from other people so they don't sneeze on you. when people like Donald Milton said, no, no, I mean. Donald Milton had done experiments before the COVID pandemic where it was actually able to capture droplets from people with influenza and he would able to be, get, influenza viruses out of those droplets. And so he could say, no, no. Look, even with influenza, and influenza potentially can be airborne. we probably should be prepared for COVID to be as well.

Tripp Collins 42:47

Mm-hmm.

Carl Zimmer 42:49

World Health Organization. they weren't, just sort of reluctant to say anything about it being airborne. They said emphatically in March, 2020, they said COVID is not airborne. They were very clear about it. and I think that they were just, Relying on these older assumptions, which were not, in fact true to begin with. Now, things did change. Um, and, uh, as in the United States, for example, things started to change. One big thing that came out was, COVID can spread when people are not symptomatic. So you don't even know that you're sick and you can be going around and doing stuff, and you can spread it to people. So that started to lead, you know, public health. People say like, well, maybe we should tell people to wear masks. even though we have a bit of a mask shortage, so we'll tell them to use cloth masks. It's better than nothing. it was a fast moving, messy, situation to say the least.

Tripp Collins 43:48

Yeah, so the, the book sort of, it begins and ends with COVID-19, and I think that maybe the last, 20% or so is sort of like a post-mortem timeline of how COVID played out. And, unfortunately there's still a lot of confusion at least in the U.S. about basic facts when it comes to COVID. and I want to do something I usually don't do, but I want to try to ask you a series of more like rapid fire, true false questions about COVID. is it, is this something you're, you're game to try?

Carl Zimmer 44:16

Sure I'll

Tripp Collins 44:17

Okay. Okay. COVID, was primarily spread through the air.

Carl Zimmer 44:22

probably true,

Tripp Collins 44:24

face masks reduce COVID transmission. In short, they work

Carl Zimmer 44:29

true, but what we're not saying there is that you are guaranteed not to get COVID if you wear a mask. They're not panaceas, but they reduce community transmission.

Tripp Collins 44:40

excellent. vaccines prevent, transmission and reduce severity of disease and short vaccines work.

Carl Zimmer 44:46

vaccine vaccines certainly work to, reduce risk of death and reduce risk of severe disease. The question about whether they reduce transmission was more open-ended. There was a lot of debate on this and a lot of people said, ah, they don't stop transmission, so they're useless. Vaccine can be very effective. Uh, I know you wanted to be this rapid fire, but I, I just have to like, I just wanna make sure that we're really clear on this. Vaccines can be extremely important and effective at reducing death and severe disease, even if they don't reduce transmission. However, I have seen some pretty recent research using, really big data sets and using new kinds of, statistical analysis to show that actually, the COVID vaccine was reducing transmission, studies in the Boston area, for example. And so as I understand it, yes, indeed, they also, reduced transmission.

Tripp Collins 45:50

our best estimates are around, or more than 28 million people die globally from COVID.

Carl Zimmer 45:57

True. I mean, that's The Economist, set up a a really good, tracking program, trying to make estimates. they stopped it, I think, I think in 2024. And I mean, the fact is people are still dying of COVID, COVID, COVID is still with us, so I don't know what the number is now,

Tripp Collins 46:13

people aren't really tracking it, like they were so, it may not be something we can know. the most likely origin is that the virus jumped species in a wet market in Wuhan, China, and it almost certainly did not originate from a lab leak.

Carl Zimmer 46:29

we can't deal with, certainty about the origins of COVID because we don't, if someone were to go into the Wuhan Institute of Virology and, pull out, a beaker from a freezer that had SARS cov to two that was collected in, say 2018 or something like that would be, some compelling evidence that it actually came from a lab. If someone had been able to find, a progenitor of SARS cov to two in an intermediate mammal host. Of the sort that was sold at the, Juan on market in Wuhan, that would be also very compelling. We don't have either of those, so, you know, so you have people looking at what information we do have, and, and they're drawing different conclusions. So there are intelligence agencies that with low confidence are pointing to the lab. there are others that are pointing to, a natural spillover at the market. and, you know, certainly there are a number of papers that have been published that have pointed at the market. Numerous lines of evidence that point to a scenario where it starts, it's in circulating in bats in, in, south, southeast China or maybe Laos. and then the, you know, spills over into some, you know, maybe a raccoon dog or something in that area. The wildlife trade then tra transfers infected animals to the Huan market in Wuhan where people get sick from it. And so there are a lot of different lines of evidence that a number of scientists have published, peer reviewed papers pointing in that direction. There's no, there's no comparable amount of scientific literature that substantiates that. It came from a lab.

Tripp Collins 48:26

And, last one here, we're not well prepared in the US for the next pandemic.

Carl Zimmer 48:31

Oh, that's totally true. Absolutely. 100%

Tripp Collins 48:34

one.

Carl Zimmer 48:35

I That's an easy one. That's an easy one.

Tripp Collins 48:38

Yeah. No, no thanks. I mean, just like it goes to show, you know, like even though more or less all the answers to those were, you know, I thought going in were true. But you know, you need the proper caveats and you need the proper understanding of. it's not easy, right? it's not easy to give straightforward answers to these things. and so I can sort of understand a little bit, the difficulty that the public is having in understanding what, what actually happened, and what was going on with COVID. But the lab leak thing is a little crazy though because of the, I'm sure you've seen the White House website with the lab leak theory website. And so I, I didn't have strong opinions until I saw that, and then I was immediately convinced that, that it could, that it was definitely not a lab leak, right? Like that was like the least credible, source of information I could possibly, think of.

Carl Zimmer 49:29

I like to talk to scientists who are expert in this area. people who, for a living study, how viruses evolve, study how new diseases emerge. study viruses in animals and so on. And, some of them will be very firm. They'll say, like, we know that it spread in the, it was a market spillover. And we know that we understand this better than the origin of HIV or influenza. These other diseases, there are people I've talked to who say that, and then there are other people who are again, real experts in the field say like, I don't think we'll ever really know. You know, like, I don't think the evidence, I mean, I don't think this evidence is strong enough. And not only that, but we're not gonna be able to get more evidence, you know, if, if it was. You know, if it was in one of these intermediate hosts, like you can imagine that, there was a farm somewhere outside of Wuhan where they had an outbreak of this, and those people, you know, like the Chinese perhaps at the behest of the Chinese government, you know, just killed all the animals and buried them. So they're like, you know, just like the way that we kill chickens for bird flu. And so the answer would be in a pit somewhere, and we're, we're not gonna find it. So, yeah, no, it's a tough situation to be in, especially, well, I mean, the political dimensions obviously make it all, that much tougher. the political dimension of this is quite astonishing, because. You know, the White House now claims that it's a certainty or near certainty that COVID was a lab leak. And because the National Institutes of Health was, involved with some research that was going on at the Wuhan Institute of Virology, therefore the White House has used that as one of their key justifications for cutting the budget of the National Institutes of Health by over 40%. Not just, they're not just cutting COVID research, but, and they are cutting COVID research, but they're cutting everything, Alzheimer's, cancer, everything. And somehow this claim that, COVID was a lab leak, is a justification for that. that's not science.

Tripp Collins 51:47

yeah. I wanna go exactly there. So, so right now we have, in the United States, people in the highest levels of government who are motivated to defund and, and otherwise erode faith in institutions, especially scientific institutions. They're, being propped up by documents like the subcommittee report on COVID, which promotes the lab leak, theory and accuses Dr. Fauci of a coverup. and, for whatever, mistakes were made in the public communication side of things, Fauci, was a good faith actor. he was a sincere guy. Right. so I guess my question is, what role do you see, for science books and maybe what is your hope for airborne in particular in terms of shaping public understanding of health and risk?

Carl Zimmer 52:30

I hope in the long term that it can give people a sense of how difficult, it is to make scientific advances. science is not simple. Science is not easy. there are people who have been right. In different, scientific inquiries and have been repudiated, by their peers and have died in obscurity. but it's still important that people keep pushing to try and understand, uh, you know, understand the world and understand, how the world works. unfortunately, yeah. Right now in the United States, we are dealing with, some serious, political moves that are based on denying how the world works. it's not just limited to, vaccine denialism, which we're seeing on display with the way Robert F. Kennedy is appointing, people. Saying nonsense about vaccines to a vaccine advisory committee. there's that. But then there's also our Environmental Protection Agency has decided that, trying to, deal with climate change is a cult. That's what, that's the word they use. So, it's may take a lot more than one book to, deal with what we're going through right now. Yeah.

Tripp Collins 53:48

I will add that science is difficult, but it is 100% worth doing and it's a good investment. when the. Us public pays for science. it comes back, depends on exactly what you're talking about, but it's a return on investment that's hard to get elsewhere. science pays off for sure. I want to ask a little bit, about book writing advice. I know you teach at Yale, and you have lots of great advice on your website, including a list, a reading list, you have there over 48 articles and seven books which you've assigned in the past. so I just wanted to ask specifically about writing books. Is there any advice you have for anyone aspiring to write their own science book?

Carl Zimmer 54:28

I have been, asked by people, about that over the years, from time to time and it's been really nice to have conversations with them You know, a few years later I see a book and it's a really good book, and I feel like, oh, I hope I was able to help in a little bit to get people on their way. I would reiterate something I said before about my own experience, which is that I would recommend to anybody that, they shouldn't just look for an idea for a book, just so that they can write a book. they need to have a story or an idea that is just possessing them, you know? they have no choice but to write it. And it also has to be something that really warrants being a book, you know, in other words, book length as opposed to, you know, something that would be a good. Magazine article or op-ed, you know, some things you can say in 500 words or a thousand words, and there are other stories that, you need to tell at 80,000 words. so, you know, if you do the worst thing is to end up with something where you're just sort of padding it out and it's not, very compelling. You know, you want the reader to be turning pages to find out what happens next. That's the goal at least. So, yeah. And I guess the other advice would just be to really think seriously about how you're gonna write it. in terms of it being a project that's going to probably take several years. Um, uh, you know, like how, how is that gonna fit in with your regular life? Lots of people make it happen, but it is just something that you have to be thinking about explicitly, that it's not just going to, it's not gonna write itself.

Tripp Collins 56:18

Yeah. so you, on your website you have, a list of seven books. Silent Spring by Rachel Carlson, Moonwalking with Einstein Joshua. Foer Calling animals by name, Vicki Hearn, encounters with the Ark Druid, John McFee, the making of the atomic bomb. Richard Rhodes, breasts and natural and unnatural history florence Williams and I contain multitudes, which is Ed Young. I just wanted to know if you wanted to comment in particular, any one of those books or maybe add a book to that list, to you what makes a great science book

Carl Zimmer 56:51

I would say that, I immensely enjoy all those books. I am not pretending that those are like the seven best books written about science ever. I could make that list longer. because there are, you know, uh, there's plenty of room, at the top in terms of, great science books. those in particular, I listed, as books that I have taught from in terms of having people read them, and also like books that give you a sense of The incredible variety of things that you can write about, under the rubric of science books. I mean, and those are very different books from each other. a book about, Oppenheimer, putting together the atomic bomb and a book about breasts, different books. but they're both really good. and they're all, they all afford opportunities to actually, to get into science. but science as not just some abstract process or some boring thing you learn in a lecture, in some lab where you're cutting up a dried up frog. But science, as part of what we live, part of our experience, you know, like science, you know, diving into the science makes our own experiences. it helps give them more meaning. And so, those are the sorts of things I look for in my books.

Tripp Collins 58:07

I'll just mention, a recommendation since we're on the topic, of one that paired really well with your book, and that is, everything is Tuberculosis by John Green, which is a totally different approach to a science book. And, it takes, it's more of the human dimension, the human story of one kid in particular, but the lens of, that we have a, you know, tuberculosis is largely preventable, but due to, political will, it still occurs in countries, Countries that don't have the funds to treat it the way, the US and other, countries in the West do. I just wanted to throw that out there

Carl Zimmer 58:41

Yeah. Yeah. And that, and that's another, yeah. I mean, and that's a more that's just came out, uh, just recently and, and it's great that, that Green is, is spreading the word about tuberculosis because, um, you know, it. We were very focused on COVID and understandably so, you know, and because so many people have died of it. but tuberculosis just year in, year out, just grinds away at humanity. And so over a million people die of tuberculosis every year, and billions of people are, are carrying the bacteria in their lungs and have, you know, may, may have suffered from it. So, it's really valuable to have someone make people aware of this, because if we had, you know, enough will and or an organization and momentum, you know, we could. We could make incredible progress at, beating back tuberculosis. I mean, all the tools are there, the testing, the antibiotics, all sorts of other things that, could be put into practice. And as Green points out, they're just not, and people are dying. people are dying unnecessarily. But unfortunately, a lot of the existing, efforts on trying to control tuberculosis are under threat because the United States has, just decided to no longer fund, a whole range of really effective programs that were in place. So, unfortunately, despite Green's book, I wouldn't be surprised if maybe in three or four years you're gonna see tuberculosis rates climbing ever hirer. It's a completely avoidable disaster.

Tripp Collins 1:00:15

Wow. what topics are you most excited about exploring, right now in the near future? is there any project that you wanna talk about?

Carl Zimmer 1:00:25

I've been, working on a podcast of my own, my first, where I've been hosting it, it's about aging. And so that's been coming out this spring and got some more episodes to go. And so I've really enjoyed working on that. I've reported on, aging research in the past. but, it's really, come to the fore, in terms of the popular consciousness of aging in a really big way, And there are a lot of podcasts that, will tell you like, oh, you need to do this, you need to do that. Um, and then you'll live forever. And, I was bringing a, you know, a, an approach to it, based on, you know, interviewing, a bunch of experts who've been doing some really interesting research. so, you know, hopefully a, a hype free, look at, you know, why we age in the first place, what we can real realistically expect in terms of extending lifespans. Or we can do simply to have a healthy span, a healthy lifespan, a health span, as some people call it. Will we be able to ever cure Alzheimer's? Why has Alzheimer's been so difficult? so it's been, yeah, that's been my, my most recent, obsession.

Tripp Collins 1:01:29

Yeah. Awesome. That's, obviously that's always been a topic interesting to people, but I feel like it's, hitting a cultural peak, right now. I'd be very interested to, check out your podcast. so if people are interested in the podcast or your books, um, where should people go? How do they best find you and support your work?

Carl Zimmer 1:01:45

Uh, probably the best place is just my website, CarlZimmer.com,

Tripp Collins 1:01:50

Awesome.

Carl Zimmer 1:01:51

I've got all my information on the podcasts and books and newspaper work and so on.

Tripp Collins 1:01:56

well, thanks Carl. I have pages and pages of notes that I didn't even get to. So just for the listener, I mean, there's just so much, interesting, stories in this book. We didn't have time to, get to a lot of what I wanted to talk to. So you should go out there and get the book if this conversation was at all interesting to you. This has been Carl Zimmer. We've been talking about airborne, the hidden history of the life we breathe. Carl, this has, been an absolute honor and pleasure for me, so thank you so much for your time.

Carl Zimmer 1:02:23

Well, thanks so much for having me. It's been great.