#117 - Stanley Perlman, M.D., Ph.D.: Insights from a coronavirus expert on COVID-19
Episode Stats
Length
1 hour and 44 minutes
Words per Minute
185.00526
Summary
Dr. Stanley Perlman is a Professor of Microbiology and Immunology and the Chair of the Department of Pediatrics at the University of Iowa. He has been researching coronaviruses for over 40 years and is currently working with his lab to better understand the more severe diseases that affect humans.
Transcript
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Hey everyone, welcome to the drive podcast. I'm your host, Peter Atiyah. This podcast,
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head over to peteratiyahmd.com forward slash subscribe. Now, without further delay,
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here's today's episode. I guess this week is Stanley Perlman. Stanley is a professor of microbiology and
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immunology along with being a professor of pediatrics and the chair of virology at the
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University of Iowa. Stanley has researched coronaviruses for nearly four decades and his
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lab is currently using mouse models for SARS-CoV-1 and SARS-CoV-2 to better understand the more severe
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diseases that affect humans. I've wanted to talk with Stanley for a few months now. Understandably,
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he has been incredibly busy. We have been part of a collaboration that is working on a longer study,
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trying to understand the durability of immune response and the impacts of that, which we
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discussed very briefly at the end of this podcast. So most of our contact has actually been through
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that, but as we got a little bit of breathing room in and around our other projects, inclusive of
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the one we're working on together, we decided it made sense to finally sit down and have this
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discussion, especially as a beautiful extension of the discussion that I already had with David
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Watkins. So I do recommend that you would listen to these podcasts in that order. The one with David
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Watkins, of course, goes over the immunology a little bit. Here we talk specifically about
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coronaviruses, including the sort of common cold coronaviruses. And of course, more importantly,
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the three versions that really have caused incredible damage to humans, none more so than the one we're in
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today. In this episode, we talk about a whole bunch of things that, again, just you can probably
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imagine interest me to no end. When we're talking specifically about SARS-1 and MERS, what did they
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teach us about this coronavirus? What does our knowledge of this coronavirus today versus what
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we knew, say, five months ago, tell us about how this story ends? And what do I mean by ending?
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All of these are topics that we get into, along with a very interesting discussion around the
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therapeutic side of things, the vaccination side of things, and ultimately what could happen again.
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So without further delay, I hope you enjoy my conversation with Dr. Stanley.
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Hey, Stanley, thank you so much for making time to talk today. I've wanted to speak with you for a
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couple of months now. And I know when we first connected, it was just nuts. And you said,
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hey, Peter, thanks for reaching out. Can we talk when things calm down a little bit? And I was
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so gracious, first of all, that you even took the time to respond. And then, of course, now we've been
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able to work together on a separate project that maybe we'll talk about down the line.
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But I'll tell you, the reason I reached out in the first place was really the result of something
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that my research team came to me and said, which was, look, Peter, if you want to understand
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coronaviruses, you've got to speak to Stanley Perlman. Everybody is an armchair coronavirus
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expert now, but you actually want to talk to the guy who was studying coronaviruses before they were
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sexy. And that's Stanley. So before we get maybe into how you became obsessed with coronaviruses,
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how did you get involved in medicine and immunology per se?
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Well, I actually started, I obtained a PhD many, many years ago in the areas actually of cell biology
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and developmental biology and virology. So I did a whole potpourri of training as a PhD student.
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And then again, during postdoc, and then I went to medical school. So there was a period there where
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I learned, I didn't do coronavirus research, but I learned how to do research. And so then when I went
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to medical school, I became interested in pediatrics and in infectious diseases. And I don't know what
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my plans were exactly when I started medical school, but became really interested in how
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baby brains interacted with viruses, which was not good. So when babies are getting infected with
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viruses, especially in utero, it's often has devastating consequences. And I worked with somebody
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who was really good at thinking about those babies. And I became just interested in research
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issues around how viruses interact with the brain. So at that time point, I became interested. It
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turned out that coronaviruses in mice provided a model that could lead to potentially important
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information. So I went from all the other things that I did and from being a pediatric infectious
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disease person, part of my training, I also started working with coronaviruses.
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Now, what was the decision point that had you leave sort of a pure academic track, which you
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would have been on from your PhD and your postdoc to sort of take that, I don't like to use the term
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backwards, but I think you sort of get what I mean, take that backward step and go back to something
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remedial like medical school. In other words, what really drove you to want to have a clinically
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active research focus? Well, I think there are two things. One, I was interested in,
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I felt I was getting compartmentalized in a small area of research. I don't think I
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wanted to be in something that was quite so confined and didn't have too many relevance for
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general health issues. And the second thing is ironic. I started my PhD at an early age and it
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was almost like I was looking for a chance to take a little bit of a break. A medical school
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and residency is more than a little bit of a break, but it was pretty fast. It was a total of
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starting medical school to finishing fellowship was only six years, which is a long time, but not
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compared to what most people do for this kind of training. It was a combination of both those
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things of being wanting to really step back a bit and also wanting to find more relevance for human
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disease. You're kind of a Doogie Howser because how is it you could do med school and because today
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med school's four years, pediatric residency's three, and then pediatric infectious disease would
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You'd be talking about a 10-year training program that you did in six.
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So I was lucky because when I did went to medical school, there was a shortage of doctors and there
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was one or two programs that allowed people to truncate their medical school training. I went to
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one in Miami that if you had a PhD, you could basically do the whole thing in 22 months. And what
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you did is you cut the first year down to six months, the second year down to about three months,
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did the entire third year, and then you did the fourth year in eight weeks. So at the end of it
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all, we did everything. And we could do it. The people had PhDs, though. I have to say they took
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PhDs in whether it be physics or physics to psychology, to biology, to chemistry. So people
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had different amounts of training. The training was good. The classes were really full of people who
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were really creative and thinking about things. So it was generally intense, but a very good
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experience. And you were well-trained at the end. So you did your residency at Boston Children's
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or fellowship or both? Both, yeah. Both. So at the time, and probably still to this day,
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Boston Children's Hospital remains easily in the top three in the world, perhaps along with CHOP and
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SickKids and maybe a few others. So you're at the sort of premier pediatric hospital in the world.
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You're training with, I guess you're referring to Brazelton as your mentor there?
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Yeah, yeah. So tell me more about childhood development. I mean, I don't know much about
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it, obviously. And it certainly rings a bell when you say that viruses can really wreak havoc.
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One of the few things I remember from OBGYN is the lengths you would go to to ensure that a mother
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Yeah. So we don't understand everything about this, but certainly viruses that invade the brain
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during the first trimester really cause devastating loss of neurological function. And the later you go in
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the pregnancy, the more likely it is to cause less disease. But even when you're infected during
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delivery, babies infected with certain viruses have hearing problems, visual problems, and even
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cognitive problems. So the babies, just because they're developing, they're incredibly sensitive to
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anything that disrupts their development. And when I think about it, the direct relationship to what I
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later did with research was really not so strong. But it was just the whole notion of could you do
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anything to prevent these viruses from spreading in the human brain? And then also, the way they do
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spread within the human brain, could this be something that would be useful for understanding
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other functions if you did this in an experimentally infected animal? So that's the kind of the way. And
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then coronaviruses turned out to have this interesting ability to cause
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demyelination, or which was similar to what we see in multiple sclerosis.
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So it sort of ended up in a long, roundabout way for my studying this multiple sclerosis-like disease
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Maybe this is probably just as good a time as any, Stanley, to really give people a bit of the lay of the land on what a
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coronavirus is. Because anybody listening to this, when they hear coronavirus, they're thinking of SARS-CoV-2.
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It might be helpful to put that in a much broader context, which is, what does a family of viruses
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actually mean? When we say the Joneses and the Smiths, we're talking about a family, not Billy Smith
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So the coronaviruses are like any other set of viruses. Their viruses are put into that category
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because of what they look like under the microscope, what they look like under the electron microscope,
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how they make new viruses, the kind of replication strategy, we call it, that they use to make new
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viruses. In the old days, you might have some serological testing that would tell you about
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relatedness. I say in the old days, we still use that, of course, but we have genetic ways now to
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really see how close viruses are. So you put all those things together, and particularly looking under
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the microscope, we can say coronaviruses have a certain pattern under the microscope.
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And all viruses that are coronaviruses have those patterns. It doesn't mean that they all can infect
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people or they all can infect this animal or that animal. They're really very, very different.
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And the ones that were known before SARS came about really were the experimental ones, like the ones we
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use, which infected mice. And then also these other coronaviruses that infect swine and cows and cats
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and dogs. And even now they're finding viruses that are not quite coronaviruses, but are very closely
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related that affect insects and snakes. So these viruses infect across lots of species. And bats,
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of course, we know, because that's been made very clear in the COVID-19 outbreak, because that's where
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this virus undoubtedly started, at least distantly.
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So is it safe to say that coronaviruses as a family, probably when compared to any other family
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of viruses, flaviviruses that produce hep C that otherwise would have nothing in common,
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about the only thing that's true of viruses is they need a host to replicate. Is that about where
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the similarities end across the broadest discrimination of viruses? Or are there other
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things that are uniquely, I mean, I guess they all have either DNA or RNA, but typically not both,
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right? Yeah, except maybe HIV seems to have both.
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But generally they have one or the other. Depending on the amount of genetic information
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they have, they can do more or less functions than other viruses. There's these gigantic viruses
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or these giant viruses, as they're called, that seem to have almost all the material. You need to
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almost be a cell, they're not a cell, but they have a lot of their own material for making proteins and
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RNA. Most RNA viruses just have the genetic material for programming the functions needed to reproduce
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the virus and also make the proteins that cause the structure of the virus, that form the structure
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of the virus. So those are simpler viruses. Coronaviruses have the unusual characteristic of
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being huge. So the genetic information of a coronavirus is about four times that of the poliovirus,
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and yet the virus doesn't seem to do that much more than poliovirus. So a little uncertain exactly
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why it needs all that genetic information. And when you say huge, Stanley, do you just mean the
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amount of RNA in it, or do you mean the actual diameter under an electron microscope as well?
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The amount of RNA in it. Certainly the coronavirus is bigger than the poliovirus,
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but that's because it has all this genetic material stuffed into the middle of it.
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Can you put it in context for us? If you take the genetic material contained within a typical
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coronavirus, how does it stack up against a human gene? I mean, the listener might not understand what
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base pairs look like or how many kilodaltons we're talking about, but just contextualize it in some
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way. Well, let me see how I can do that. Because it's big for a virus, a gene. If you took genes and
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laid them side by side, it could be equivalent to 15 human genes laid side by side in terms of length,
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but human genes have variable length. So if it was a longer human gene, it could be fewer of those
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for the viral genome. This particular virus codes around probably about 25 or so different
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proteins, varying size. A lot of them are pretty small. So it's a lot of information, but it's not
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compared to the human genome, which has 20,000 genes. It's a very tiny amount when you think about 25.
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And does it, like human DNA, contain coding and non-coding segments alike that are just as important?
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No. Human DNA contains both non-coding sequences within genes and non-coding sequences outside,
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and the vast majority of the human genome is not for coding. With a virus, the vast majority is for
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coding. There may be stretches here and there that are spacers, as it were, between genes, but they're
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real in a minority. So the strict answer to your question is yes, there's parts that are non-coding,
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but it's a tiny fraction compared to the amount that actually codes for genes.
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Just to go down the path of some speculation, do we have a sense of what the evolutionary pressure
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was for coronavirus? I've never really stopped to think about it, but it always struck me as viruses,
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unlike bacteria, don't really serve a useful purpose. I mean, it's true that maybe most of them
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don't directly harm us, but if you eradicated this planet of bacteria, we would all die pretty quickly.
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We live in a very healthy symbiotic relationship despite a pathologic relationship with a small
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few of them. But if I could conduct a thought experiment and remove every virus from this
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universe, wouldn't the world just keep ticking along fine? Or is there something I'm missing about
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their function? Well, I don't think you're right. We have lots of great examples. For example,
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in the ocean, there's zillions of viruses that interact with bacteria. I would bet if you took
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that interaction away that there would be a problem. And people talk about even in the human
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gut, there's all these viruses that people find. Some of them, I think, interact with those commensal
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bacteria and are useful. Whether they're absolutely necessary, I don't think we know as much as we do
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about commensal bacterias, which are really important for human life and animal life. But I would bet
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if you took away all the viruses in the world, sure, you'd eliminate some of the ones that cause
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human disease or non-human animal disease. But I think you might get away from others that
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are actually beneficial. Yeah. So there might be some knockoff effect where they're helping
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something that's second order to us. They're helping the bacteria that are helping us or helping some
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other distant organism that's way down the plankton sub chain that I haven't considered fully.
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I think that that's a possibility. And then bacteriophage on bacteria are going to be even
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different than the ones directly on human cells. But there may even be animal viruses that have
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roles that we don't understand very well that are important. I know there's some animal viruses that
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interact. Insects have a relationship with each other and the animal viruses have an important part in
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maintaining some of the developmental patterns in those insects. I can't tell you,
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I know that some of them are wasps, but I can't tell you more if I remember. But there's definitely
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viruses that without which there would be problems. So I'm sure you're tired of telling this, but I
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think everyone should know this by now. But if not, why does it derive the name coronavirus? What is
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the corona referring to? If you look under the electron microscope, it has these projections from the
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surface of the virus that look like either the corona of the sun or the corona of the crown.
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So I think the first people who saw it under the electron microscope decided to name it based on
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that. You have to have a little imagination, but it's not so far off. And of course, this is relevant
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when we start to talk about the immune response to it, because the immune response is particularly
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strong when it comes to certain parts of the viral code. And we'll probably come back and talk
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about spike proteins and things like that. So when did these coronaviruses show up in terms of our
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understanding of common colds? I think we identified the first one in the 1930s and 40s
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for chicken. That's what I remember, that the infectious bronchitis virus was found in chickens.
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And then in the 1960s, people identified viruses that caused the common cold that had the same kind
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of appearance as the infectious bronchitis virus. And I think by then we knew something about some of the
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pig viruses as well. So the human, it was isolated from people with colds and had the same structure
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as coronaviruses and chickens and pigs. So that's how they knew it was in the coronavirus family.
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Is it the exception or the rule, Stanley, that a virus that infects humans also has an animal host?
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I think I would say it can go either way so much that it's hard to make a strong conclusion.
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Viruses like measles virus infects only people. Smallpox only infects people. That's why we can
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eliminate them from human populations in theory. Viruses or the coronaviruses mostly seem to be able
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to infect other animals as well. But the virus that I worked with for years in the lab, mouse hepatitis
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virus was a mouse virus. And I don't think it affected anything but mice. The human viruses,
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even now, so we're seeing that SARS-CoV-2, the cause of COVID-19, can infect animals. So humans can
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infect these other animals by spreading the virus. SARS-CoV certainly infected other animals. MERS-CoV
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is really a camel virus. So by definition, it infects other animals. The human common cold coronaviruses,
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at least one of them can infect other animals. And I don't know, one of them probably came from bats,
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but I don't know if they can infect bats. So I think coronaviruses usually can go across species,
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but I don't think always. And other viruses often can go across species, but not always. And
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it's really going to play, as I was saying, into the ability to eliminate a virus from the human
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So if you're keeping track of all the things that make a virus difficult for us as a species,
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so if you're trying to build a super virus, having the ability to go into an animal host is an
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important feature of that. Because you can basically, quote unquote, hide outside of the
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humans for a while, even while a large population of the humans are either vaccinated or acquiring
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natural immunity or even approaching herd immunity. And you can effectively lay dormant outside of the
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Maybe. When you think about different viruses, certainly that's true for West Nile virus. If
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we have the best vaccine in the world, we still have West Nile virus floating around with birds and
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other animals. Of course, West Nile virus really isn't a human virus. It's a virus that ended up in
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humans at the end, but it wasn't really the intent, as it were, of the virus to infect humans.
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Others, like measles, did just fine with infecting everybody and having huge amounts of herd immunity,
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and still every three years or less coming out and infecting human populations again.
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Is that because the R-naught of measles was just so high that it was like you just had one little
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crack in the dam and it was a disaster, whereas for most things like influenza or even coronaviruses,
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Yeah, I think that that certainly contributes to it. With measles, you had five people out of a hundred
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not vaccinated or not resistant to the virus. Those people would get infected if you put them
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in a room with somebody who was positive for the measles virus. Same thing is true for smallpox too,
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where it spread out an animal host. Others, I don't know, for other, polio, I don't think of polio as
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having much of another animal host. I think that it continues to be in human populations, mostly because
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poor vaccination and because we use live attenuated vaccine that ended up in the water and either
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mutates or doesn't mutate, but it's not gone. And so where did those viruses come from? If they
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never had an animal host, where did they evolve? Well, I think they did initially have an animal
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host. So measles is thought to evolve from winter pest, which affects animals in Africa. You see,
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that's the other thing about the animal host is if you evolve from an animal host, the virus evolved
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from animal host, but then change so much to infect humans, they may not be able to then cause an
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infection in the animal host. So these, like the SARS-CoV-2 that causes COVID-19, we don't really
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know what it would do if you put it back in bats. No one's going to try, but I don't know if a bat
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would be infected by it because it may have changed enough, even in the little bit of time it's been
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out of the bat. So it can't infect the bat very well anymore. Wow. That's really interesting. So it
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ping pongs back and forth until it finds a more favorable host. I mean, this would suggest from an
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evolutionary fitness standpoint that if it starts in an animal, comes to a human, stays in a human,
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it must find the human on some level, a more desirable host. I don't know, but that's making
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the virus a little more anthropomorphic than it might be needed. If it's in humans, it may never
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see a bat again. So it's not that it's more desirable hosts, but that's a fair point. Yeah.
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Humans, bats don't interact that much, even though they interact more than maybe desirable given these
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viruses. But it's not like the virus can look around and say, oh, there's a bat. I think I'll...
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Yeah. Let me go try that out again and see how it compares to this.
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Last question on this topic. Tell me a little bit about HIV. I'm just not a student of my immunology.
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Is HIV a virus that is now believed to have evolved? I mean, I know back, I remember a million years ago,
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people said, oh, it came from this monkey or that monkey. Do we have a very clear sense of the
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lineage of HIV? I think it's beyond what I know well. I think that we have a very strong sense
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that it came from non-human primates. I think we may know more exactly, but what I read periodically
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is some studies, it seems like the virus was in human populations or identified way before its
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first obvious entry into people who became HIV infected. So I think it's clearly from non-human
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primates, but the exact details, I don't know. But I think some people do. And some of these sources,
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like some non-human primates have an HIV-like virus that's pretty close.
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Let's go into the, let's say it's the late nineties. So it's pre-SARS. You're working
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hard on coronaviruses. At that point in time, is it, am I doing the math right that there are
00:23:36.740
basically sort of four endemic coronaviruses that are not especially severe, but just circulate
00:23:43.180
through humans causing annoying respiratory infections year after year? Is that directionally
00:23:49.180
the lay of the land? It's actually only two in the mid nineties because two of them
00:23:53.040
discovered after SARS in 2004 or so. Wow. Which were the two that came along and that
00:23:57.900
were there in the nineties? 2290 and OC43. Okay. And what did we know about people's
00:24:06.080
immune response to them? I mean, did anybody ever say, Hey, we should vaccinate against these
00:24:10.040
or was it, they're not that interesting. They don't make people that sick. Who cares?
00:24:13.640
Yeah, it was more of the latter appropriately. So if you're going to spend a huge amount of money
00:24:18.120
and we know that huge amounts of money are involved in making a vaccine, why would you
00:24:22.000
spend it on a cold virus? People get cold. It's annoying. The other thing is that really
00:24:27.140
that may be relevant to the thing about COVID-19 is that people who got these cold viruses, they
00:24:32.360
could be reinfected. So they could be reinfected a year later. And that's what the papers we were
00:24:38.700
talking about earlier really talk about is that the immune response may be, if you have a mild
00:24:43.840
infection, you may have a more transient immune response. Yeah. There are three or four papers
00:24:49.120
that I can't wait to dive into and we're going to do it. I just want to make sure the listener
00:24:52.560
doesn't get too lost in what we're talking about. But actually, if you're listening to this now and
00:24:57.000
you have not listened to the interview with David Watkins, this would be a great time to hit pause,
00:25:02.440
go back and do that. Because in that discussion, we really do the immunology
00:25:06.400
tour de force. And we explain the difference between the innate immune system, the adaptive
00:25:11.400
immune system, and the two branches of the adaptive immune system, the humoral system, which relies on
00:25:17.020
B cells and their antibodies, and the cellular system, which relies on T cells. And I have a very
00:25:23.180
strong suspicion that very soon Stanley and I are going to get into some of the weeds around the B
00:25:29.020
cells versus the T cells. And again, I don't think you can educate yourself enough on this topic if you
00:25:34.040
want to truly understand what's going on with these viruses. Bringing it back to the late 90s,
00:25:38.560
tell me what your interest was at that time. So obviously, you're a scholar, you're doing
00:25:44.040
incredible work. Did you think at that point in time, gosh, these coronaviruses aren't that
00:25:49.140
interesting. They're not really a threat to humans. They're not really a threat to my patients in the
00:25:53.400
way other viruses are. Even RSV would be more of a threat to children. Whooping cough would be more of
00:25:58.840
a threat to children. What is it that kept you in this, at the time, relatively benign virus?
00:26:05.680
Was it, help me understand, was it kept you in a field that ultimately turned out to be a very
00:26:09.600
productive decision? At the time, we were interested mostly in this mouse virus and
00:26:14.200
the human disease multiple sclerosis. So thinking about how does a virus go into the brain, end up in
00:26:20.940
the cells that make myelin, which are the sheets in the brain that cover the axons. And how does the
00:26:27.380
virus end up there? And then once the host realizes that the virus is there, how does it manage to
00:26:34.940
destroy tissue while it's eliminating the virus? How come the virus, the immune response, can't figure
00:26:41.660
out how to rid the cells of virus without also destroying the cells themselves and destroying the
00:26:48.240
function of their cells? So that's what I became interested in. That's what I was really studying.
00:26:52.240
How does this occur? What kind of immune responses were elicited by the virus? What mattered the most?
00:26:58.820
What caused demyelination and what caused remyelination, which is the process of getting
00:27:03.300
myelin back and which is in people with multiple sclerosis is the period when they have remissions
00:27:09.000
after relapsing and permissing or after relapsing have disease and they get better again for a bit of
00:27:15.260
time. For people who have some form where they get better to a large extent, how is that occurring as well?
00:27:21.780
So we were using the virus to try to study that.
00:27:25.020
But to be clear, was your personal interest at that time more in, this is a virus that helps us
00:27:30.720
understand a disease like MS, where we can understand the demyelination, remyelination process?
00:27:36.920
Or was it more, I think from a pediatric and a neurobiological development standpoint,
00:27:42.440
I want to make sure I understand what's happening in trimester one that is potentially injuring a
00:27:48.640
child's brain? Those two aren't necessarily mutually exclusive, but were you bent more towards one
00:27:54.460
I think that by the mid-90s, I was thinking much more about the first. How does a virus infecting
00:27:59.460
the brain, how is it cleared? Why does clearance always involve tissue destruction? Why is that
00:28:06.520
So you're basically now becoming a neurobiologist with a background in immunology, virology,
00:28:11.920
Well, at that point, I became a neurobiologist with a background in virology and cell biology. I
00:28:18.740
didn't really start doing immunology till the early 90s, 1990s. So then we were doing some of it,
00:28:30.220
So tell me what's going on when SARS hits. What is it? I can't even remember exactly. Was this 2002,
00:28:36.160
The end of 2002 became a big deal in 2003, and then it was eliminated in July, 2003 for
00:28:44.840
So tell us the story in some detail. I think for many people, it's, I mean, I remember it because
00:28:49.080
there was a component that was in Toronto. I grew up in Toronto. I wasn't living there at the time,
00:28:53.740
but just that sort of perked my ears. But at the same time, I was in residency. So I was so sleep
00:28:59.320
deprived. If I could drive home without crashing, that was an accomplishment. So it's not like I was
00:29:04.060
really paying attention either. But can you give us sort of a really detailed account of where this
00:29:08.800
virus came from, how it emerged, and what impact it had on you and how it may have shifted your
00:29:13.880
Yeah. So the way it emerged, we heard about this virus that was causing a respiratory disease in
00:29:20.600
southern China. And initially, we all thought this was going to be a kind of flu virus because flu
00:29:25.840
viruses, we know, initiate, often start in southern China, particularly in the city of Guangzhou,
00:29:31.580
which is across the bay from Hong Kong. So we heard about these viruses. And then it became
00:29:36.740
clear that they were a coronavirus. This was isolated by several laboratories. What we learned
00:29:41.960
in retrospect is that they actually came from a live animal market in Guangzhou. And this was a place
00:29:48.920
where animals were all put together for sale for food and other purposes. And so there were bats along
00:29:55.200
with other exotic live animals. And we learned that the coronavirus, the SARS coronavirus, was almost
00:30:02.380
certainly a bat virus that spread to these other animals. And the virus rapidly adapted to these other
00:30:07.840
animals and sometimes infected human handlers of that market. So people were actually handling the
00:30:13.420
animals to sell them. And many of those became sick. Many developed subclinical disease. And we know
00:30:20.700
that up to a third of the handlers actually had antibodies to SARS-CoV. So we know that this was
00:30:25.740
going back and forth a lot. Then we know that some of the time it spread to mainland China. How many
00:30:32.000
times that occurred, we don't know. Whether it was exactly the same virus that we study in the lab,
00:30:36.980
I don't think we really know that well. The reason that this became really, was brought to the world's
00:30:42.600
attention is that a single animal handler became ill enough to see a physician. The physician
00:30:48.560
actually became quite ill, didn't go home, rather went to a Hong Kong hotel. And at that point,
00:30:55.640
it was really sick and spread the virus to the other people on the floor. And they all went to
00:31:01.060
their homes. And that's how the virus ended up spreading around the world, because of this one
00:31:05.780
physician who ended up going to Hong Kong. Whether this would have occurred anyway is an open question,
00:31:12.260
of course. The main set of events was a single event. And that's why the virus seemed to start from a
00:31:18.280
single point source. Now, help me understand something. I think most people listening to
00:31:22.700
this are now familiar with R-naught, but we'll explain it again. What was the R-naught of that
00:31:28.340
SARS virus? In retrospect, I guess, what do we believe it was? How transmissible was it?
00:31:33.080
Yeah. So this is a good question, because the official numbers has an R-naught of about two to
00:31:38.920
three, which means that a single person will infect two to three people. So clearly, as you can see,
00:31:44.040
without even thinking about it very hard, if a virus starts with one person, then infects two,
00:31:49.460
and then each of those infects two more people, you now have four infections, they infect two,
00:31:54.020
you get eight. So you can quickly get up to high numbers by this exponential growth.
00:31:59.540
And we'll hit pause there for one sec. Just to put that in the context, earlier, for example,
00:32:04.180
you talked a lot about measles. Measles has an R-naught probably north of 10, correct?
00:32:08.880
Yeah, around 15. I mean, that's about as high as they come. I mean, that's an explosive
00:32:14.220
exponential multiplier. At the other end of the spectrum, today, HIV's R-naught would be
00:32:21.340
less than one. Yeah. And I think that HIV is a little different because it's not a respiratory
00:32:26.440
spread. Yeah. So let's use another respiratory example. What would be a low R-naught? Well,
00:32:31.420
let's use the other coronaviruses. If you take those other coronaviruses, they're one to two at most,
00:32:35.800
right? Exactly. So one person infects someone else on the average. This is on the average,
00:32:40.720
of course. So going back to now SARS, sorry to interrupt you there, but now you've got
00:32:44.680
a two to three R-naught. So this is quite a spreading virus. This physician goes to the hotel,
00:32:51.360
he gets a bunch of people potentially sick. And obviously now that can take the virus around the
00:32:56.860
world because presumably people at hotels are going to go back someplace, right?
00:33:00.000
Yeah. So I think that the R-naught of two to three though may be misleading because there's
00:33:07.000
no question that the R-naught on the average was two to three, but it consisted of spread within the
00:33:13.420
hospital. Spread occurred much more readily. SARS was a virus that really caused pneumonia and not
00:33:19.140
much more. So the virus didn't readily spread from one person to another until that first person was
00:33:25.480
pretty ill. And then if that person went in the hospital and you now started, as it were,
00:33:30.580
mucking up their lung fluids so that virus was now released into the air by procedures, either
00:33:37.000
intubation or suctioning or whatever else needed to be done, then the R-naught factor would be much
00:33:43.120
more than two or three. And the community, because this is a deep pneumonia, it really isn't that
00:33:48.360
contagious. So I think that if we split it up, those 8,000 cases would be an average of two to three
00:33:54.180
with quite a range depending on where the virus was acquired. And I think the other lesson we have
00:33:59.720
to take away from SARS is it gets widely quoted as having a 10% mortality rate. But again, how could
00:34:07.660
we possibly say that when we don't know the total number of cases? That might be the case fatality
00:34:12.800
rate. I mean, case fatality rate is not that interesting. It's the infection fatality rate that
00:34:18.180
really matters. And it's certainly possible, isn't it? That many more people had it. Even let's say
00:34:24.780
there was five times the number of people who actually had the illness, but didn't come down
00:34:30.140
with a severe enough version that they warranted hospitalization or testing. You would all of a
00:34:35.860
sudden say, technically the mortality of this is 2%, which is still absolutely devastating virus.
00:34:41.320
But it's not the devastation of... When you hear 10% mortality, I mean, that's literally like playing
00:34:48.640
That's the way that I think about it. But it was very hard at the time finding patients who are
00:34:52.920
asymptomatic and were infected. So the thinking was that anybody who became infected actually became
00:34:58.460
symptomatic. What you say makes perfect sense. But I'll tell you another story. So the next coronavirus
00:35:04.280
that came upon us was the MERS coronavirus, the Middle East respiratory coronavirus. And this is a disease
00:35:10.340
that's very similar to SARS and being a deep lung disease. This disease, the mortality is billed at
00:35:18.800
35%. So really terrible. And it's different though. So what you just talked about, the 2002 to 2003
00:35:26.560
virus that started in a market in Southern China, who has the same name as the current virus we're
00:35:32.440
talking about, but we refer to them as SARS-1 and SARS-2, they're in the same beta family, which we
00:35:38.200
didn't really get into. Do you want to take a minute to explain that? Because MERS is a slightly
00:35:42.360
different subdivision of the family. Can you help people understand that nuance?
00:35:46.560
Yeah. So it's all very similar. They're all in the same general group of coronaviruses and within
00:35:52.940
the same subgroup of coronaviruses, but they're slightly different in their genome organization
00:35:58.340
and in some of their coding. So they're put into a separate category.
00:36:02.240
So it's a coronavirus. Before we knew so much about from sequence, they would have been considered
00:36:07.820
the same type of coronavirus, but it's different enough. So we classify it a little differently.
00:36:12.620
What that means is it's a little more distant from the SARS coronavirus. So there's less thinking
00:36:19.640
that one could actually provide immune protection from the other. Though in fact, there's some cross
00:36:25.060
reactivity. MERS coronavirus is recognized in part by SARS coronavirus sera from people who survive.
00:36:31.700
But they're close. It's like your third cousin instead of your first cousin. It's pretty close,
00:36:36.940
but not as close. And this will obviously be interesting when we come back to this discussion
00:36:42.100
of cross-immunity. And basically that's probably the biggest difference as opposed to a functional
00:36:47.100
difference about the virulence or the potential for virulence, correct?
00:36:52.240
Okay. So again, let's now pick it back up. It's what, is it 2009 when MERS came along?
00:36:56.660
Well, MERS and camels probably came along at least in 1983, but in people, it was found
00:37:03.360
in 2012. And that's the earliest cases. There's a few mysteries about MERS coronavirus. Why
00:37:13.160
So tell me about that. Did people, and when I say people, I really mean scientists. I'm sure
00:37:17.100
the population wasn't wandering around thinking about this, but did scientists appreciate that
00:37:21.420
there was a coronavirus in camels in the eighties from the early eighties? Was that something
00:37:29.080
Nope. This was absolutely not appreciated because in camels, these coronaviruses cause the common cold.
00:37:36.640
So that's why nobody would care. Camel gets a cold. You don't even know. He goes to camel
00:37:41.000
Walgreen and you never hear about him again. So what do we think accounts for the virus jumping
00:37:48.920
quite literally from a camel to a human in call it 2012-ish?
00:37:54.140
We don't know. The virus had been in camels since the late 80s and probably earlier. It worked
00:37:59.480
earlier. And we know it doesn't jump in Africa or other parts of Asia. So this is a real mystery
00:38:05.660
in this virus. Why is it only in the Arabian Peninsula?
00:38:08.700
When you look at the MERS virus in the camels, it's still the same in the Arabian Peninsula versus
00:38:16.040
other camels? Hard to know. It may be subtly different in parts of Africa where there's no
00:38:22.180
MERS, but we have a lot of trouble saying that those differences account for the fact that there's
00:38:27.320
basically no cases in Africa. And you have these cases in Saudi Arabia rising all the time now.
00:38:33.200
And when you say Africa, do you include North Africa? Were there any cases that arose in Egypt or
00:38:42.040
They did not occur in those places? Yeah. Camels are infected there, but people are not.
00:38:47.160
Oh, wow. Because a lot of people would sort of say, look, I mean, if something happens in Saudi
00:38:50.820
Arabia, it would be just as likely to happen in Iran or Egypt. I mean, even though they're
00:38:55.660
technically belonging to different continents, they're very similar geographically. But you're
00:39:00.200
saying no, there was a really hard line distinguishing that. And we don't to this day have
00:39:05.700
a sense of what allowed that jump. Yeah, we don't know. The fact is not only
00:39:11.200
occurred in 2012, but it's occurring once or twice a week now. Because people are coming in
00:39:16.220
who actually have no contact with camels and are coming into the hospital with MERS. They often have
00:39:22.880
comorbidities. They're older or they might have diabetes, but otherwise they don't even have contact
00:39:27.120
with camels. And they have to get it from a camel, but not clear how. So wait a minute. That was my next
00:39:32.120
question. Do we know that it can or cannot spread human to human? Once a person gets it from its most
00:39:37.660
likely source of transmission, which is a camel, can one person infect another? Yeah. So this is
00:39:43.180
where the R-naught factor becomes important again, because the official number for MERS is somewhere
00:39:48.420
between zero and four. I think outside of hospitals, it's probably near to 0.35, 0.5, somewhere in that low
00:39:55.000
range. So it means it's not impossible, but all you need is somebody to be infected and happen to
00:40:01.860
infect someone else who's highly susceptible. And that highly susceptible person will then appear at
00:40:06.660
the hospital not having had any contact with a camel. And that zero to four, which is such a broad range,
00:40:13.480
I've read that as the official range, it's so broad as to be unhelpful. That's really the camel R-naught.
00:40:18.960
That's the spread from camel to human. And then as you said, human to human transmission is probably
00:40:25.340
going to occur in the hospital. And so MERS becomes the scariest of them all just on mortality because
00:40:32.080
the official numbers are basically it killed a third of the people that were infected. It's about
00:40:36.800
almost 900 deaths out of call it 2,500 confirmed cases. That's about as scary as any virus, maybe outside
00:40:45.980
of Ebola. But again, the absolute numbers are so low, the transmissibility human to human doesn't
00:40:53.840
seem as high, especially when you consider that the scariest viruses are ones that are transmitted
00:40:58.200
from asymptomatic people, right? Yeah. So this one, like SARS, is mostly transmitted from people who have
00:41:04.040
lung disease already, who have severe lung disease. I don't think the R-naught is actually camel to camel.
00:41:09.360
I don't think it takes that into consideration. Rather, what it takes into consideration is the
00:41:13.840
hospital spread. It's like SARS and so much hospital spread. And that's been basically not stopped
00:41:19.520
completely because as my friends in Saudi Arabia say, somebody comes in with this disease, we think
00:41:25.400
about it quickly, but we may not think about it in every case quickly enough. So there may be still
00:41:30.760
some spread within the hospital. So nosocomial spread, which you're referring to in hospital spread,
00:41:35.880
is a big problem because you just don't have it on the front of your mind that every person who shows up
00:41:41.960
in respiratory distress could have this. And therefore, A, potentially the healthcare workers
00:41:46.860
themselves can be infected because it's not just the proximity, but it's the type of procedures that
00:41:51.180
are being done. When you put a breathing tube in somebody, you're really creating an effective portal
00:41:56.220
for the virus to get to you. And then obviously we know how infections like that can spread through
00:42:01.900
intensive care units and such. Yeah, that's exactly right. That's exactly why it's a problem.
00:42:07.220
So why did this not turn into even an epidemic within the Arabian Peninsula? I mean, you did
00:42:15.280
mention that we still see a few cases each year, but 2,500 confirmed cases directionally makes it not
00:42:21.900
even a sort of an epidemic really, let alone a pandemic. Why do you think this just wasn't something
00:42:28.280
that spread despite its potential for devastation at the mortality level? Because I think that that
00:42:34.080
R0 of 0.3 really makes it not possible or not likely. There's plenty of cases with MERS where
00:42:40.220
people went back to a relatively poor country after having been a worker in Saudi Arabia, were found
00:42:46.080
to be infected and infected nobody. So that nobody became ill from that patient, even though they
00:42:51.220
weren't really looked at. That's as opposed to Korea where there's that one patient who infected 186
00:42:56.280
people. So there was really a confluence of lots of bad luck for that to have occurred.
00:43:01.300
And then going back to SARS-CoV-1, what basically accounts for the eradication of that? Call it
00:43:09.960
in 2003, 2004. The combination of there being no reservoir. So it's not like camels, which could
00:43:17.160
continue introducing to human populations. And the fact that because you weren't contagious till you
00:43:23.240
were sick, it was easy to look at somebody and say, aha, that person has SARS. We're going to stick
00:43:27.580
him in the room by himself, take care of him and make sure he infects nobody else. Then you would
00:43:32.900
stop the disease. It's a classic kind of quarantining, identification and quarantining that we talk about
00:43:38.260
over time with COVID-19. But it was really feasible with SARS when you're talking about a total of 8,000
00:43:44.320
cases around the world. I mean, Stanley, to hear you tell the story this way, it's just, it's like a bad
00:43:50.540
movie. Because you could be lulled into a false sense of confidence by the time MERS blows over.
00:43:57.080
You can say, hey, okay, I got it. You've got a few of these coronaviruses. They cause a bunch of
00:44:02.040
colds. You get a runny nose in the summer, but it's really nothing. And yeah, it's true. Two really
00:44:07.160
bad actors showed up that on a virus to virus level can really hurt their host, but they're nothing to
00:44:13.840
really be afraid of. In the case of SARS-1, it has two things that make it really friendly to humans.
00:44:21.420
One, it can't bounce back and forth between humans and animals. And two, you don't really spread it.
00:44:27.700
You're very unlikely to spread it if you're not symptomatic. You don't have to shut the world down,
00:44:33.540
but not only that, you get to isolate people when they're sick and treat them before they treat
00:44:38.660
others. So the virus really gave up two big potential superpowers. In the case of MERS,
00:44:44.260
sure, it lives in animals and it's never going to leave those animals, but it has such a poor
00:44:49.620
ability to spread between humans almost under any circumstance, unless you're probably sticking a
00:44:53.940
breathing tube in them, that it was just so easy to contain. If the story stopped there, you'd say
00:45:00.060
coronaviruses are just not a threat to us. Yeah. So I think some people in the field more than me said,
00:45:07.120
let's go look at coronaviruses in bats. And so what they did is they found other coronaviruses,
00:45:14.340
and it was actually for a scientific reason, a different one than just searching for the viruses.
00:45:18.860
We were trying to figure out where did the SARS coronavirus really begin? So people went and looked
00:45:23.760
at bat colonies throughout China, since that's where SARS began, and asked, can we find other bats,
00:45:32.000
other bat viruses that are more similar to SARS-CoV than the ones we know about right this minute?
00:45:37.120
Because we could isolate the virus in the wet markets in Guangzhou, but we didn't know where
00:45:42.600
they came from exactly, which kind of bats. And it was just a trick finding it in bats. And so,
00:45:48.700
but while doing that, people found other viruses that could, in theory, enter a human cell by using
00:45:55.540
the same kind of mechanism that SARS-CoV used to enter human cells. So there was some people who were
00:46:02.680
saying, there were a lot of people, some people in the field who were saying, well, we potentially have
00:46:07.120
more of a problem because there may be other ways to infect people, but there may be other viruses that
00:46:13.340
can infect people. And so I think there was a concern that this could happen again. And MERS is the same
00:46:19.080
thing. We haven't identified the exact precursor to MERS in bats, but there's clearly viruses that look
00:46:25.020
like the MERS coronavirus in bats. And so if they were able to use the human receptor and didn't take
00:46:30.800
too much adaptation to infect humans, then you can imagine the same thing occurring with MERS sometimes
00:46:36.420
in the future, occurring again with SARS-CoV-like viruses. So you're right, in 2015, we were thinking
00:46:43.080
these viruses really caused bad pneumonia, but it's going to be like influenza H5N1. It's going to have
00:46:49.540
very, very, very little human to human spread and mostly animal to human spread. Is there a necessary
00:46:56.880
relationship that says the viruses like MERS that are incredibly deadly if you get them,
00:47:05.340
just luck is on our side and they don't have much transmissibility, or is that simply luck so far
00:47:11.400
and there's no reason to suggest teleologically that that has to be the case? In other words,
00:47:16.480
you could imagine a scenario where you take something that has the transmissibility of
00:47:22.340
SARS-CoV-2, which we'll get to and explain why it is much more of a headache than SARS-CoV-1 or MERS.
00:47:28.760
If you take the transmissibility of that, which is both, and primarily is a factor of the fact that
00:47:33.580
it can spread before you're symptomatic, coupled with the actual pathology of MERS, which I want to
00:47:40.800
contrast with these viruses, I mean, that's a double whammy. You can really get into a dangerous
00:47:46.580
situation. Not that this hasn't been a disaster, but it could be a 5X disaster. Is there anything
00:47:53.480
that tells us that's unlikely because of this feature of the biology of the virus?
00:47:58.360
I don't think there's anything that's unlikely. I don't think there's anything about the feature of
00:48:03.880
the virus. I think about this as SARS-CoV-2 being a mixture of the common cold coronavirus
00:48:09.080
and then a mix of plus either SARS or MERS coronavirus in the lungs. So that's why you
00:48:15.320
have the transmissibility and the severe disease because it does both. But when you think about
00:48:19.720
other bad diseases, like even in the epidemic flu in 1918, that really did about the same thing.
00:48:25.920
It was very, very, very transmissible and it killed about a few percent of the people infected.
00:48:31.000
But if you infect everybody and you kill three percent or four percent, you're killing a lot
00:48:35.320
of people. So that's what this virus is doing also because it's transmissible so readily because it
00:48:42.160
behaves like a common cold coronavirus. That rate of lethality is not super high, but the denominator
00:48:49.040
is so huge that you have a lot of people dying from it. Is there something about the pathology of this
00:48:54.460
virus? How does it differ? I mean, when you think about SARS-1 and MERS, that let's just say
00:49:00.840
directionally those numbers are right in terms of the denominator wasn't bigger than we think and
00:49:05.280
you're killing basically one in 10 or one in three people infected. What did the virus actually do in
00:49:11.040
the lungs that would render people so helpless? Yeah, I think it's the same thing that SARS-CoV-2
00:49:16.780
does in the lungs. In those people who get severe disease, I think we don't really understand what's
00:49:21.900
going on. We think that there's lots of virus in the lungs and we think there's a very strong and
00:49:27.000
probably inappropriate immune response that's causing much of the damage that we see in lungs.
00:49:32.660
So it's a combination of those two features. That's why people are, from the beginning with
00:49:37.140
SARS, people are trying to figure out a way to both limit virus replication and also decrease the host
00:49:43.760
immune response so that you don't have this extra result of an exuberant immune response.
00:49:49.480
Do the other two viruses, SARS-1 and MERS, do they also gain entry through the ACE2 receptor or did
00:49:56.440
they use a different receptor to enter the pneumocyte? Well, SARS uses the same receptor. MERS uses a
00:50:03.340
different receptor. One thing that's really curious is SARS doesn't affect the upper airway to a
00:50:07.940
appreciable extent, even though it uses the same receptor. There's also one of the common cold
00:50:12.720
coronaviruses, NL63, uses ACE2, only affects the upper airway and doesn't affect the lungs than the
00:50:18.860
appreciable extent. And that could also account for the change in transmissibility because if you are
00:50:24.180
only infecting the lower airway, you're probably less transmissible than SARS-CoV-2, which can infect
00:50:30.980
both. Exactly. Exactly. That's why SARS was not so contagious because it only stayed in the deep
00:50:37.720
lungs until you went to the hospital and had that tube put down for breathing or some other procedure
00:50:42.900
done. So do you think that SARS-1 and MERS were so much more lethal than SARS-2 because they elicited
00:50:51.620
a greater immune response once they infected the lung or because they caused greater pneumocyte damage
00:50:58.040
when they infected the lung? I think that it's actually because they all cause the same amount
00:51:02.980
of damage or pretty similar, but you have this huge denominator in SARS-CoV-2 of people who have mild
00:51:08.240
disease. So I think that if one way to look at these numbers, and this is not a perfect calculation,
00:51:14.220
but if you have with SARS-CoV-2, MERS-CoV-2, there were a hundred people infected. They all get
00:51:19.540
some variability, some variation in pneumonia, and you have a certain mortality rate ranging from 10%
00:51:26.340
to 30%. SARS-CoV-2, of those hundred people, maybe 20 of them are going to get the lung disease. The other
00:51:33.880
18 are going to be asymptomatic, subclinical, have a cold, have something in the upper respiratory
00:51:38.900
tract. If you now take that 20% as your denominator and divide the 6% mortality that we're seeing,
00:51:46.820
the 5% mortality, I don't know what the number is exactly, but let's say 5% by 20%, you have a 25%
00:51:56.360
So just let me make sure I understand that. Are you saying it's more the law of large numbers and we
00:52:01.340
have such a big denominator with SARS-CoV-2 that you're going to normalize more, or are you
00:52:06.080
comparing case fatality to case fatality, whereas I'm thinking of it as the IFR as opposed to the
00:52:12.480
CFR for SARS? Because I think the IFR of SARS-CoV-2 is very population dependent, but I think it's much
00:52:20.260
closer to 1% to 2% than the initial numbers that people feared of 5% to 10%, which would put it more
00:52:27.000
in the ballpark of SARS-CoV-2. That's the way I used to think about it when this first started.
00:52:32.280
In January and February, the mortality rate was 2.8%. And now if you look at anything official,
00:52:37.960
it's near to 5% to 6%. So what you say makes perfect sense, it should be near to 1% to 2%,
00:52:43.280
but it's been hard to prove that by all the official numbers. So what I was saying more is that if the
00:52:50.660
mortality rate in SARS and MERS, out of everybody who was sick, all had pneumonia. And of those
00:52:58.500
people, some number died. In SARS-CoV-2, if only one out of five people or less actually get pneumonia,
00:53:06.060
then the fraction that died, if you use that same fraction who died over that 20%, you basically are
00:53:13.240
multiplying your number by five. So if your number is 5%, then it goes up to 25%. If it's 3%,
00:53:19.040
goes up to 15%. So where we are exactly, I don't know, but it may be that the upper transmission is
00:53:25.680
the readily transmissibility of the virus is what's really making the number so huge and that everything
00:53:32.320
else it's doing is consistent with what SARS and MERS did if you confine yourself to just looking at the
00:53:37.800
lower respiratory tract disease. Now, this is something that might be a little bit outside of
00:53:42.780
what you've studied, but I'll ask anyway. One of the lingering questions, there are so many
00:53:47.620
that I have comes down to the survivors. I mean, obviously we think a lot about the mortality of
00:53:53.640
this, but if you take a person who gets infected and they're not asymptomatic, so we know that a lot
00:53:58.900
of people kind of don't even know they've got SARS-CoV-2 and the only reason you figure it out is
00:54:03.620
after the fact, serologic analysis tells us that they did. But there's a non-trivial amount of people
00:54:09.080
who get sick as hell and they get what they would describe as the worst cold of their life.
00:54:13.560
I have at least two friends I can think of in this situation who three months later can barely
00:54:19.940
run a nine minute mile again and they're slowly getting back in shape. When I did a quick check
00:54:25.660
on this, looking at the SARS-MERS patient follow-up data, I didn't find a heck of a lot that told me
00:54:32.140
about long-term lung function. Do you know much about this? And I would imagine that there's now
00:54:36.440
more of an interest to go back and assess that than there was three months ago when I tried to look
00:54:40.940
this up. Yeah. Even before this all occurred, I asked my friends in Saudi Arabia about follow-up
00:54:45.920
on the MERS patients. And I could never get information as to what exactly was going on.
00:54:51.200
I suspect that they had problems, whether they be forever or a few months is unclear, especially
00:54:58.420
since your friends were younger and fitter. If the MERS, particularly MERS, if it's mostly older
00:55:04.720
people, people with diabetes, people who have comorbidities, they may take them longer to get back
00:55:10.320
to baseline. It's probably not going to be running miles. I suspect it'll take a while to get back.
00:55:16.360
I don't know how much fibrosis was at the end of it all, how much permanent damage there was.
00:55:21.320
I suspect that there was a fair bit, but you always have it. You know, like in SARS, people
00:55:26.580
always talk about neurological disease without actually ever finding the virus in the brain.
00:55:31.820
And then it was attributed to being on ventilators and corticosteroids for long periods of time,
00:55:37.440
contributing to cognitive dysfunction. And occasionally the virus was in the brain.
00:55:42.580
So it's all a mix that's hard to really sort out what the major components are, because there's
00:55:48.040
several things that contribute to the outcomes. Well, based on your knowledge of coronaviruses and
00:55:53.640
your knowledge in particular, their impact on the brain, do you think that there are plausible
00:55:59.240
mechanisms by which, even for those who recover from SARS, there could be lasting neurologic impact
00:56:06.980
that is not the byproduct of hypoxia or vent head, pump head, any of the other more mechanical
00:56:14.840
or other physiologic accounts? In other words, do you believe that there is a plausible scenario by
00:56:19.380
which the virus could have residual neurologic value?
00:56:22.700
We can't find any evidence of the virus in the brain, but it seems less likely that it's
00:56:31.420
Yeah, that's what I was going to say. If you take a disease like Kawasaki's in children,
00:56:35.380
we know that that's a disease that is mediated by some sort of immune response. We don't know
00:56:40.920
if it seems here like COVID-19 is somehow provoking this response in this very, very small subset of
00:56:47.720
children. That certainly leads to consequences in the heart, long-term consequences, or it can.
00:56:54.060
So you can certainly imagine scenarios like that. How often this occurs and what's going on exactly,
00:57:01.340
So between the resolution, so to speak, of MERS and where we were, call it a year ago today,
00:57:08.660
Stanley, where was your head at with respect to the big one? Were you in the camp that said,
00:57:14.760
yeah, I've carved out a pretty nice niche here. I'm going to be studying coronaviruses forever.
00:57:19.180
Or was there a part of you that said, this is a threat to national security, to the world?
00:57:23.220
There's a pandemic brewing here. I mean, how did you think this could unfold?
00:57:27.140
I certainly wasn't smart enough to predict that there was going to be a pandemic.
00:57:30.340
As I said, some of my friends were worried about additional infections in humans. I don't know that
00:57:34.960
anyone would have predicted a pandemic like this one.
00:57:38.740
I want to pause you there for a second. Why? I mean, not that I did, but I want to push on that for a
00:57:43.780
moment. All the ingredients were there. I was going to say is the Department of Defense
00:57:48.120
in 2010 or 11 put out a report about possible emerging viruses as being really the major threat.
00:57:57.020
And Bill Gates talked about this. I mean, it's become a very well-known
00:57:59.940
TED talk that is, it's painful to watch now because of how accurate it was. So you have,
00:58:05.960
you have these two examples of viruses that have enormous potential to cause harm,
00:58:10.940
but fortunately for us at the time, they just don't spread well. A few tweaks, i.e. infection
00:58:17.680
of the upper respiratory tract and a slower onset to symptoms would easily double your R-naught.
00:58:24.980
But okay, fair enough. I'll stop coming down on, I'm joking, of course, stop coming down on you guys
00:58:29.400
for not thinking this could happen. But so let's fast forward now to when did you first hear about
00:58:35.280
the outbreak in China? I mean, I'm assuming it was early December, late November?
00:58:38.480
No, I don't think it started quite that early. I would say late December. The first cases,
00:58:44.000
official cases were in December. We think there may have been some in November, but
00:58:47.240
I think that the people in China, scientists and doctors in China knew something was going on in
00:58:52.400
December. And then it was eventually reported very early January. So I think we knew a few weeks
00:58:57.980
early. But even then, we didn't really know how much human to human transmission there was.
00:59:03.180
Now, I have to say that at the time, given the number of cases, we should have guessed
00:59:06.620
that something unusual was going on. But to the SARS epidemic, we had these cases and lots of people
00:59:12.380
were infected. And we didn't really know how the spread was occurring. And at the time, by early
00:59:18.600
January or mid-January, we had 800 cases in the world. So it didn't seem to be extraordinarily
00:59:24.760
different from these other viruses. Maybe if we had had more information about what was going on
00:59:30.120
in Wuhan, we would have realized, aha, this is doing something that's different than what SARS and
00:59:35.220
MERS did. But we didn't have that information. When did it become clear to you personally that
00:59:42.460
this was going to be a much bigger problem than SARS and MERS ever were?
00:59:47.980
Funny you ask that, because I remember in December, when we really didn't know anything
00:59:51.400
about human to human transmission, I spoke to my friends in China. And I got off the phone and
00:59:55.920
told my wife, this is a big deal. So I'm not sure what I was basing that on, because it wasn't so
01:00:00.700
much evidence of human to human transmission. It was pretty clear to me then that this was going to
01:00:05.580
be a major problem. At that time, could you have predicted it would have been this big an issue?
01:00:11.580
I don't think so. Mostly because all the previous diseases had remained geographically confined.
01:00:18.960
So SARS was really a disease in China with a little spread around the world. MERS was really a disease
01:00:24.320
in the Arabian Peninsula with that one case in spreading, infecting several people in Korea.
01:00:30.800
But this one, you know, and maybe the dynamics of everything are so different. People spread travel
01:00:36.240
from Wuhan much more frequently because people have more money. So they fly more, they take the train
01:00:41.540
more. So that helped the spread a lot. And of course, this is transmissible. The other thing is that we had
01:00:47.180
gone through some of this with H5N1. So in the late 1990s, people were saying, all we need to do is have
01:00:52.520
this to be transmittable and it'd be a disaster because we don't really have good immune responses
01:00:57.220
to it. And it never happened. So yeah, what happened in 2009 with H5N1? Because the skeptics
01:01:04.100
would say, hey, we don't need to worry about this SARS-CoV-2. The last time we cried that the sky was
01:01:09.900
falling, it didn't fall. Right. So that was H1N1 in 2009. And that started off as a lethal disease
01:01:17.620
was identified in Mexico. It seemed to have a high lethality, but it's more cases became
01:01:22.520
clear, identified. It's clear that it didn't. It just was lots of cases and very little mortality.
01:01:30.220
It was influenza. It was just a variant of influenza. It wasn't H5N1, which causes a severe pneumonia.
01:01:39.260
No, H5N1 is the one that's never made it to human populations to an appreciable extent.
01:01:47.940
Yeah, it's mostly pigs and birds, but it kills birds and most flu doesn't kill birds. So the
01:01:53.120
concern was that it would change to infect, to be transmissible human to human, but it never did.
01:01:59.900
So same thing with thinking about coronaviruses. They hadn't done this so far. We certainly thought
01:02:05.460
they could do it. But this is an interesting question is how do you prepare for a pandemic
01:02:11.180
that you don't have? Because it's something I've been asked about and thought about. So you're
01:02:17.220
sitting there in 2005 and SARS goes away. How do you decide what kind of resources you're going to put
01:02:23.600
developing antivirals, developing vaccines against SARS, a disease that doesn't exist anymore?
01:02:29.680
The way the American system is set up for this, if you have a good idea and you propose to the NIH,
01:02:35.700
you have a good chance of getting funding. But on the other hand, if you're competing against other
01:02:39.880
grants that make more compelling arguments for funding and deal with diseases that are actually
01:02:45.640
present, they're going to look better to a study section. So you have to figure out a way to identify
01:02:51.120
a disease that could be a problem without going overboard and using lots of resources for diseases
01:02:59.540
I mean, it seems that you'd want to structure it in a way that says, look, there are some
01:03:03.080
no regret moves here for any viral infection. And then there are some things that are going to
01:03:10.300
be very specific. So for example, not that this is an NIH question, but what would a national stockpile
01:03:17.260
of PPE need to look like? What would an electronic infrastructure for contact tracing need to look like?
01:03:24.880
What would a national stash of reagents to develop serologic and PCR testing need to look like?
01:03:34.600
So we don't know what the gene sequence is, but the moment we know the gene sequence,
01:03:38.700
wouldn't it be great if we could hit go and actually deliver a million tests a day and not
01:03:46.100
talk about it for three months and not do it? Those strike me as just a no regret moves. You don't need
01:03:51.380
to know a single thing about what's coming other than it is infectious. It's the little stuff. It's
01:03:57.060
the nasal swabs. It's the reagents. It's all the stuff I just said. And about 20 other things I've
01:04:02.280
been thinking about that kind of, I really hope that when this is said and done, this doesn't get
01:04:06.880
forgotten because it's not a staggering investment. When you consider what we spend on healthcare and
01:04:12.620
defense, which are disproportionate to any other country by a log order and oftentimes by two log
01:04:18.580
orders per capita, you put a few billion dollars into this type of resource and you consider it
01:04:24.800
more vital than you would consider our national surplus of oil or other things. For example,
01:04:30.620
most people I would assume know this, but if not, we keep an enormous supply of oil on hand.
01:04:36.520
If the world shut down and we couldn't get a drop of oil from anyone in the world, we would at least
01:04:42.100
have, I don't know, I don't remember these stats, but probably a 60 to 90 day supply of complete
01:04:47.600
independence on oil, maybe more than that. And that's just a national defense imperative. So
01:04:52.320
this should easily be in that front. The other thing on the therapeutic side, I would say is
01:04:56.920
don't we already have enough evidence to suggest that at least one avenue to treatment is immune
01:05:03.900
modulating therapy. So maybe not antiviral because that can be quite specific, but all of these diseases
01:05:09.900
have an enormous component of an overactive immune response, which we'll discuss. And therefore having a
01:05:16.340
huge stockpile of immune modulating drugs to be appropriately dosed also strikes me as a no
01:05:23.020
brainer, right? Yeah. Yeah. No, you could argue that. I'm not sure that these diseases are all the
01:05:28.580
same in terms of the cytokine storm type activity, but they may be close enough so that your point is
01:05:35.480
well taken. They are similar enough so that that would be a reasonable thing to do is to have those on
01:05:41.720
hand. I think that's what Bill Gates was probably talking about more than specific drugs against
01:05:47.120
specific viruses, because you don't really know those so well. Think about it. So the whole stuff
01:05:52.500
with ventilators and all that, that was really poorly done. Testing, I think once we know, you're
01:05:58.720
right about nasopharyngeal swabs and mechanics of being able to do the testing, the actual identification
01:06:04.100
of targets for like RTP, PR are not that hard. I mean, that probably took four days to figure out.
01:06:10.900
But it took longer to scale up. I mean, I think that's the point, right? It's not no, I mean,
01:06:15.020
the virus was sequenced January 11th or 12th, wasn't it? Yeah. Yeah. Early in that, actually.
01:06:20.100
It's just scaling up the ability to do testing. So anybody who says, well, come on, it would be
01:06:25.700
crazy to have $3 billion invested in that on the off chance that the virus doesn't even make it out
01:06:31.440
of China, to which the answer would be, did you look at what happened to the US economy? It's called a
01:06:35.800
hedge. This is what sophisticated companies do. Sophisticated companies hedge their bets. And if
01:06:42.160
the answer is every time a really scary virus emerges in China, we have to spend $3 billion to
01:06:47.780
be ready for it to land here. But guess what? We don't have to shut our economy down as a result.
01:06:52.960
We can instead mitigate 90% of that damage. I mean, that's the wisest investment that could ever be
01:06:58.280
made. But I'll get off the soapbox now because nobody wants to hear me rant about that stuff. I want
01:07:02.740
to get back to kind of the interesting biology on this stuff. So let's now go back and talk about
01:07:08.160
these four viruses that cause us nothing more than nuisance when we get colds. Do they have any
01:07:14.200
seasonal variability to them, by the way? Are they winter viruses, summer viruses, or does it matter?
01:07:19.020
They tend to not be summer viruses and they tend to be more winter, early spring viruses.
01:07:23.960
What determines that, by the way? Is that simply a function of being close to each other in the winter
01:07:28.040
and spreading it? Or is it actually a property of the virus?
01:07:30.520
Yeah, we used to think it was that. But as we know more, I don't know the answer to that. I know
01:07:35.080
that some of these respiratory viruses are more active in the late fall, winter, and others in
01:07:40.660
the winter, early spring. And I don't know why there's a difference. I don't think anyone else
01:07:44.720
really knows either. We know these viruses are usually happier when it's a little cooler and a
01:07:48.860
little drier. But that wouldn't explain why one virus did well in November, another one did better in
01:07:54.280
March. Interesting. And then from an immune response, why is it that these viruses haven't
01:08:03.440
basically become irrelevant in the sense that we all eventually get them and we all develop immunity
01:08:08.860
and we're sort of done? That's really the question about all common cold viruses, whether
01:08:13.340
they be corona or otherwise. So why do you actually get reinfected? I don't think we understand it very
01:08:18.880
well. We know that there's an antibody response to these viruses. It seems to wane. It goes away.
01:08:24.400
We know that you need a specific kind of antibody, the IgA response, that seems to help. We don't have
01:08:30.060
that much information about IgA responses. They seem to wane as well. The T cell response is the other
01:08:35.920
part of the immune system that you mentioned earlier. We don't know that much about the T cell
01:08:40.720
response in common cold coronaviruses. Before all this began, we didn't think that was a big deal
01:08:46.040
because common colds usually go away in a few days before you actually have a T cell response.
01:08:51.420
So we don't know why virus immunity wanes. We know there's such huge differences. Smallpox you
01:08:58.260
can detect. And people had smallpox in 1918. In 1995, they still had antibody responses that were
01:09:04.540
measurable. Here we have these common cold coronaviruses. A year later, they've waned. And
01:09:09.840
a couple of years later, they're probably almost gone. So we don't really understand that. That's
01:09:14.800
really a key question. And it both impacts the ability to people to be reinfected by
01:09:20.180
SARS-CoV-2. It impacts the vaccine responses, impacts general herd immunity as we try to get
01:09:26.380
rid of this virus. So really important for not knowing. There probably hasn't been a case of a
01:09:31.880
coronavirus before where we've cared enough about herd immunity to talk about it. But do you mind
01:09:36.880
explaining to folks what you're talking about with herd immunity, specifically with respect to SARS-CoV-2
01:09:40.880
and what it means? Well, herd immunity is really the other side of what you were talking about,
01:09:45.760
the R0 factor. So if the herd immunity means if you have a virus that's extremely contagious,
01:09:52.420
for people who are susceptible to be protected from the infection, you have to have most of the people
01:09:58.460
around them be resistant to the virus. So to put this in a different context, if somebody who's
01:10:04.060
infected with whether it be SARS-CoV-2 or measles or anything else comes into a room,
01:10:08.860
and they're spreading virus, the virus is going to land in various places. Some of it will land on
01:10:14.460
the floor. Some of it might land on somebody's hands and could, in theory, infect that person.
01:10:20.480
But if that person is immune to the virus, it doesn't matter. The virus can land on that person's
01:10:25.880
hands and then that person can touch his face, but he won't get infected or he won't get diseased
01:10:30.580
anyway. But if that person is susceptible, then he will. So then if that person is susceptible,
01:10:36.280
he could then spread it to other people in this proverbial large room if they all stayed together
01:10:40.940
for several days. Now, if you take a situation where you have an extremely contagious virus,
01:10:46.300
so in that room of 100 people, I was saying before with measles, as five of them are susceptible,
01:10:51.780
the virus might spread to 25, 30 people from that one susceptible person. And then of that 5%,
01:10:57.900
maybe one or more of those people will become infected. If you have a virus like SARS-CoV-2,
01:11:03.920
which has a lower R0 factor, then at that same 100 people, if they're five are susceptible,
01:11:09.640
the odds are it will not get to the point of infecting one of those five people.
01:11:14.580
So herd immunity is that ratio, the fraction of people who are immune to a disease. For measles,
01:11:21.340
the number is said to be 95%. If you don't have that 95%, then measles can infect people who are
01:11:28.320
susceptible. For most common viruses, it's around 60 or 70%. So that's the number that people are
01:11:34.880
really looking at in terms of immunization or infection with SARS-CoV-2 to protect the general
01:11:41.480
population. It's not the same as being immunized or having the previous infection, you're still
01:11:46.680
susceptible. But it just means that it's much more likely the virus won't spread. And if you get sick,
01:11:52.100
it's unlikely you'll spread it to that 30% of the population that has never seen the virus.
01:11:57.720
So that's why it matters. Yeah. And there's a very non-linear but monotonic inverse relationship
01:12:04.920
between R0 and herd immunity, which I can't believe I actually just said all that. It's basically math
01:12:09.380
speak for the higher the R0, the higher the need for herd immunity, but the relationship gets there
01:12:18.200
non-linearly. I don't have a non-math way to say that, but the example you gave is a good one,
01:12:23.760
which is, and I said inverse, it's actually not inverse, it's direct. The R0 for measles is very
01:12:29.500
high and the herd immunity threshold is very high, 95%. Going down to an R0 of two to three,
01:12:37.100
you have a herd immunity threshold of 60 to 70%. Now, do you believe that based on everything we know
01:12:43.580
today, and that includes potentially there being many more asymptomatic people who are infected and
01:12:50.760
who have gotten over the infection than we previously believed, do you believe that the
01:12:54.780
threshold for herd immunity is still as high as 60 to 70% for SARS-CoV-2, or do you think that it
01:13:00.560
could be as low as 20 to 30%? Well, I think it's still going to be 60 to 70%. It's just that there's
01:13:06.540
a higher percentage of people who have immunity already. So in other words, you're saying, yeah,
01:13:12.200
it's becomes a bit of an academic or a moot point because it might be that of those 60 to 70% who
01:13:17.900
have to be infected for herd immunity, two thirds of them don't even know they were infected, but
01:13:21.620
they actually were from an immune. Okay. Fair, fair point. Yeah. So is there much genetic drift in
01:13:26.820
these viruses? The way, like influenza, I think most people know, hey, I got to get a flu shot every year,
01:13:30.980
but what they might not understand is the reason they're getting the flu shot is probably less
01:13:36.400
because their immune system forgets what influenza looked like and more because influenza looks different
01:13:41.300
every year. How much do these coronaviruses genetically drift to use the lingo?
01:13:47.000
So far, we haven't had evidence that this one drifts. I think when you look at the other viruses,
01:13:52.280
one of them seems to vary quite a bit. OC43 seems to have different variants. A lot of the others don't
01:13:58.000
seem to change that much. SARS was adapting to human populations, so it changed, but if it had stayed
01:14:04.500
around, I don't know that it would have changed much. MERS is clearly a camel virus. So any drift you see is
01:14:10.320
what happens in camels, not in people. Again, both for MERS and the human, the other coronaviruses is
01:14:16.020
not really, well, except for OC43, I don't think there's huge effects on immunity. This virus is
01:14:21.880
really, there's certainly lots of talk about changes in the virus and becoming more brilliant or more
01:14:27.300
weaker or more attenuated, but there's really no evidence so far that says this virus has changed in
01:14:33.140
a way that makes it unlikely a vaccine will work, unlikely that a previous infection won't protect
01:14:38.560
you from a second infection. There may be reasons why it won't, but it won't be because the virus is
01:14:43.800
changing so far. That's an important point. I think we want to kind of reiterate that, right? Which is
01:14:48.200
the doomsday scenario would be a virus that retains its virulence, but constantly drifts enough
01:14:54.480
genetically that your immune system never recognizes it again, but it retains all of its bad properties.
01:15:00.340
I mean, that's a disaster. If you had a new version of a deadly virus show up every year,
01:15:05.000
it could hurt you just as badly, but somehow its genetic drifting created a different coat
01:15:11.100
on it, a different set of antigens. And every year your immune system was caught off guard. That would
01:15:15.880
be very painful. And what you're saying is, hey, we don't have evidence of either of those things
01:15:19.940
happening, that it's genetically becoming more or frankly, less harmful of equal, if not more
01:15:25.560
importance, that it's not becoming a different immune animal as time goes on, at least in the
01:15:31.960
very short window we've studied it. But again, it's helpful to go back and look at these other
01:15:36.620
coronaviruses that you've studied because they've given us a lot of insight, right?
01:15:40.540
Yeah, exactly. The immunity, when you have a mild infection, just do not develop great immunity.
01:15:46.060
So let's double click on that. You've said already part of that. I want to make sure I understood it.
01:15:50.220
Part of it is the innate system, just for whatever reason, doesn't seem to do much. You've already
01:15:56.320
talked about how a lot of times with at least the common coronaviruses, they might not even stick
01:16:03.220
around long enough to develop a T cell response. Can you say a bit more about the adaptive humoral
01:16:09.480
system? What do we know about the IgM and IgG? Which again, if you haven't listened to the interview
01:16:16.500
and the discussion with David Watkins, I think this would be a great time to go back and make sure
01:16:20.540
you familiarize yourself with that so that we don't have to go into the details of what those
01:16:24.140
things mean. But six months after a person has a common coronavirus, do you still see evidence of
01:16:34.220
And do you know how often it is basically binding, non-binding? Do you have a sense of what the
01:16:41.300
functionality of that IgG is? Is it neutralizing fully necessarily?
01:16:45.720
Not necessarily. I think the human volunteer studies are best answers for that, for the
01:16:50.480
common cold coronaviruses. And they show that immunity is there, it's measured by neutralizing
01:16:55.260
antibody, and then it wanes with time. And that a year later, it's there and may not prevent shedding.
01:17:01.360
It's still, I think it sounds remarkably like what I think we're going to hear about with COVID-19
01:17:06.500
and immunity when people have mild infections or asymptomatic.
01:17:10.800
Now, we've talked about this paper that came out, God, I think it's been maybe three weeks ago.
01:17:16.020
Alex Setti was the senior author on it, 2020 cell paper that looked at 20 patients who recovered
01:17:23.300
from COVID-19. And I believe about two thirds of them actually had a CD8 T cell response and a CD4
01:17:32.840
response that kind of correlated with that. The point being, they looked to have been at least
01:17:38.000
partially aided in their response to SARS-CoV-2 from T cells that looked like they had been sensitized
01:17:45.060
by other coronaviruses. Now, this was a small study, and this was based on in vitro assays.
01:17:51.860
Can you explain that study a little bit, or at least the idea behind it? Because it's an incredibly
01:17:56.720
interesting idea, and it has clinical relevance if this turns out to be true.
01:18:00.400
Yeah, so I think this is one of actually several studies. This is the only published one, I think,
01:18:05.740
that shows that people who have never seen the virus have some sort of T cell response to SARS-CoV-2.
01:18:13.160
Now, there are some caveats when I read this paper that make me pause in drawing too strong a conclusion.
01:18:19.120
One is that in most of these papers, the way T cell responses are measured is not by functionality,
01:18:24.340
but rather by being activated in a certain way. And these activations, to my mind,
01:18:30.120
are a surrogate for actual functionality. And the functionality was not well demonstrated in any of
01:18:36.060
these studies. You may see a little functionality, but it's not the major point. Second thing is the
01:18:41.900
targets for these viruses, for the T cell response, is not the usual response that you get in terms of
01:18:47.760
targets. And you see after the wild type infection, the SARS-CoV-2 infection. And because of this
01:18:53.600
difference, it makes it also a little unclear to me where this response is coming from. So you can
01:18:58.560
say, okay, that doesn't matter. It's still from a common cold coronavirus. But then when people go
01:19:03.200
back and look at the sequence of the common cold coronaviruses for the same targets, there's actually
01:19:08.420
very little homology with T cell responses that are recognized in these patients who have never seen
01:19:15.300
SARS-CoV-2. So altogether, on one hand, you could say, well, maybe this is something that's important.
01:19:21.100
Maybe it contributes to protection, pathogenicity. On the other hand, it's a little odd because it's
01:19:27.800
mostly measured by activation, not necessarily by function. And that may matter. And it's also
01:19:33.520
targets are not totally clear how that's working. So maybe it's something that's not completely clear
01:19:39.120
yet. So I'm a bit confused by that, Stanley, because if we were doing this on the B cell side,
01:19:44.780
which is where we normally would, you would do an in vitro assay and demonstrate the presence of
01:19:52.120
neutralizing antibodies, not just binding, but neutralizing. And that would give us great
01:19:56.920
confidence that the B cell response would translate from the in vitro finding to the
01:20:02.380
in viva finding. Is that correct? I agree with you completely, yes.
01:20:06.240
So we can do comparable T cell assays where we actually look at killing function and not just
01:20:13.100
signaling functions and things like that, right? Yeah. And this isn't really signaling. This is
01:20:18.340
a protein, what was measured with proteins that come up if a cell has been activated at all.
01:20:25.560
So this is not killing assays, not even making cytokines, which are my preferred way of doing this
01:20:31.860
because it's easier. Yeah. So that's what I was going to say. Usually when you look at typical
01:20:35.860
studies that are looking at, say, response to flu vaccination, they look at cytokine response
01:20:40.520
on the T cell. So do you know if studies are looking to do that? Because that just seems to
01:20:46.260
be a very obvious thing to want to ask at this point. Well, for the people who are naive, who've
01:20:51.200
never seen the virus and who have these assays done, T cell responses are done, but they're,
01:20:55.600
they're very, very low levels of activity. So the amount of cytokine produced are extremely low
01:21:01.980
or non-existent. So you just wonder, part of the issues, we do some of these assays and
01:21:07.660
you can do it very well, but the level of the background, as it were, is approaching what
01:21:14.260
we're seeing in some of these patients. So I think jury's just out on how important it is and
01:21:19.620
what it means. To me, it's really interesting. It kind of doesn't go with what we used to see,
01:21:25.440
what we've seen in MERS patients, where we don't really see much of a background,
01:21:29.440
much evidence of cross-reactivity, but we didn't actually do the surrogate assays,
01:21:33.540
these assays for activation. And there may be a temporal component. In other words,
01:21:37.960
it could be that let's assume that on average, a person gets one year of quasi protection from a
01:21:44.980
given coronavirus until it can infect them again. You now have a hundred people who are in various
01:21:51.280
stages along a continuum of that recovery from pick your favorite endemic coronavirus. And then
01:21:58.400
they all at one day get infected with SARS-CoV-2. Well, presumably there's also a strength and a
01:22:04.160
decline of immune response. So even though they would all have some immune response lingering,
01:22:10.240
some memory of immune response to the benign coronavirus, they could technically mount very
01:22:15.720
different responses to the much more feared SARS-CoV-2 simply as a function of how far they are out
01:22:23.180
from their initial infection, correct? I think that's a different layer because it assumes that
01:22:27.160
there's something there. That's correct. If there's something there. Yes, absolutely. This
01:22:30.520
is a totally second layer. Do you think there are other viruses or other vaccines that could provide
01:22:36.560
cross-reactivity? I don't think provide cross-reactivity. There's of course these ideas that
01:22:42.120
you should immunize everybody with attenuated polio virus because that'll activate the immune system
01:22:47.520
and that'll give you some protection. You should do something like that BCG, which we use for
01:22:53.060
immunization against tuberculosis, whether they have any effect. People are suggesting this and I
01:22:58.200
think they're in trials even. But in terms of specificity of getting at the coronaviruses, I don't
01:23:03.520
think so. The BCG one's worth probably explaining a little bit to people because it got so much
01:23:08.400
attention. I think the other one that got quite a bit of attention was MMR. There's a very famous
01:23:12.960
graph that a friend of mine sent me that said, hey, the entire pandemic and the mortality profile,
01:23:20.780
which basically hockey sticks above 50 can be explained by exposure to MMR. People below 50
01:23:27.500
uniformly had MMR vaccination. People above 50, it's much more spotty. And the further you get from 50,
01:23:35.000
the less likely you were to have an MMR vaccine. And that explains it. Now I can go on why I don't
01:23:42.680
believe that's the case, but I'd rather hear your views on whether that is or is not likely.
01:23:46.240
I think it's actually contrary to what one might think because those of us who are over 50 had...
01:23:53.840
Yeah, the real and fell three of those infections. So I don't consider myself resistant. In fact,
01:23:58.840
almost everybody my age had all three of those viruses. Everybody certainly had measles and mumps.
01:24:07.640
But from an immunologic perspective, Stanley, is there any reason to believe
01:24:12.080
that your memory T cells and B cells to measles, mumps, and or rubella would offer you some
01:24:19.760
protection against this particular coronavirus? Is there any evidence that they offer protection
01:24:23.720
against other coronaviruses? No, I can say that. No one's looked very, very hard,
01:24:29.240
but there's no reason to think that it would. If there was anything like that, we would all have
01:24:33.780
some preexisting immunity to the virus that's way higher than what we're talking about.
01:24:38.660
I'll just tell you why I'm also quite skeptical of the BCG claim, which is not to say that in
01:24:44.620
certain cases, maybe there's an anecdote that it works. I mean, obviously one of the first examples
01:24:49.160
of cancer immunotherapy came out of an understanding of the Cooley's toxins that sort of came out of this
01:24:56.960
idea of BCG. But the reality of it is BCG has never shown enough specificity to be a viable
01:25:02.500
immunotherapy against cancer. And it's for that reason, I guess, even if that's overly simplistic,
01:25:07.360
that I really doubt that BCG could have a meaningful impact on a virus because it requires
01:25:13.120
just as much immune specificity as it does for the immune system to attack cancer.
01:25:18.260
Yeah. And there's other agents. So we've worked with agents that turn on interferon.
01:25:22.960
And I think if you give interferon at the wrong time in these infections, you may make people worse.
01:25:27.600
So if you were exposed to COVID-19 and you had a very good exposure right now,
01:25:31.960
and I gave you one of these agents that turn on interferon, that may well help you.
01:25:35.240
Because before you really get an infection, if we jazz up your immune system, that may help you
01:25:41.260
do better with the virus. Once it gets going, that probably isn't true. There's all these issues
01:25:46.800
that one could imagine that if you jazzed up the immune system with BCG, that it could help you if
01:25:52.580
you got it right the right day and then you were exposed to COVID-19. But I wouldn't want to be
01:25:57.320
inoculated with BCG just for fun with the possibility that in the next two days, I get exposed to the virus.
01:26:03.460
You provided a much more elegant description of how you might possibly benefit from it
01:26:09.180
in a Hail Mary, pure luck standpoint, but how mechanistically it just doesn't even make sense.
01:26:15.320
And you're right, by the way, I think the broader point I would take away from your comment is
01:26:18.760
there's a really interesting way to think about this from a targeted therapeutic standpoint.
01:26:23.120
When you think about the sophistication with which we try to treat other diseases with multiple
01:26:27.780
lines of defense, this is a great example of, one, going back to everything I said before about
01:26:34.140
when I was on my rant about how would you begin to prepare for the next time a pandemic comes back,
01:26:39.300
it's all that stuff. On the therapeutic side, I think it's being more thoughtful about
01:26:43.680
what the strategies are. The moment we identify those early cases and say, boy, this is a disease
01:26:49.600
that typically, like influenza, is a little bit more of an immune paralysis disease.
01:26:54.280
At least at one point here, you're seeing this hyperactivated immune sense. So early treatment
01:26:59.940
is antiviral with immune amplifier. Late treatment is immune modulator, antivirals long since gone,
01:27:06.760
and respiratory support starts to matter. You can start to really be more sophisticated in how you
01:27:10.860
think of these things. And I think that's probably something that people are starting to think about
01:27:15.020
now. And I suspect that a lot of the clinical trials now will focus on more partitioning. So we
01:27:20.040
don't just think of it as drug X, good or bad, drug Y, good or bad. We don't have this sort of
01:27:25.340
nonsense binary thinking. I agree with you completely because that's exactly the way I
01:27:30.100
think about this disease is that you need antiviral therapy early on and then maybe an immune modulator
01:27:36.720
later. And in terms of immune activator, if you just catch it just at the right time, maybe that
01:27:42.580
would help. I think it's actually going to be the same for severe flu, like the H5N1. I think the
01:27:47.600
same scenario applies. The other thing you point out is that with different patients in different
01:27:53.800
disease courses, one has to be ready to modulate therapy. And this is one of the things that I'd
01:28:00.220
love to have that we don't have, which are biomarkers for different stages of disease.
01:28:04.920
Well, I think for so many diseases, we know that something works well. And then we do large studies
01:28:11.100
and we find that, you know, it didn't work as well as we think. But if you go back, you say,
01:28:15.160
within this population, if we could have identified it first, that would be the people
01:28:20.360
who would have responded to this particular therapy. That's one of the reasons that some
01:28:25.740
therapies work that don't work that you might think would work. Because if 20% of people fall
01:28:31.300
in a category of benefiting from it, if you treat 100%, you dilute all the benefit.
01:28:38.520
That's such an interesting idea. What do you think some of those biomarkers could look like?
01:28:42.560
There's some obvious ones. When a patient's in cytokine storm, you can measure the cytokines.
01:28:47.720
But if you could go deeper than that, and you could look at the proteome, and you could look
01:28:51.880
at metabolomics, or look at the gut, or something like, where do you think the answer could lie?
01:28:57.440
Okay. So there's two parts of the question. First one is, what would you sample? Because
01:29:01.160
the ideal person to be sampled is that person who comes in like your friend who had trouble running,
01:29:06.600
who didn't feel well. And I don't think he progressed to having disease enough to get him in the
01:29:12.680
Nope. Yeah. Young, healthy guy in his maybe early 40s. And yeah, never hospitalized,
01:29:18.860
Right. So that's a person you'd like to do a test on and say, okay, is he going to progress or not?
01:29:23.940
Clearly, in his case, we'd want something to say, he's sick, but he's not going to progress because
01:29:28.440
he didn't progress. So that's a person who you might not want to do anything for. On the other
01:29:33.620
hand, he may look exactly like someone who has diabetes and 60 in terms of how poorly he felt.
01:29:39.200
And so what you'd want, you'd need a marker, not only for severity, but you wanted something that
01:29:43.720
would distinguish between the two of them and that you could sample easily in the blood because
01:29:47.620
your friend would not have wanted to undergo some sort of lung measurement because it would have
01:29:52.260
been way more invasive than the sickness he felt. So that's why you come back. I think you can come
01:29:58.280
back to things like cytokines and metabolic products. The problem up till now has been that you can see an
01:30:04.840
increase in cytokine X in people who are going to be sick and not increase in people who are going
01:30:09.820
to do better. But when you put them all together, it's not like you have populations that are very
01:30:15.380
high versus very low. You have ones that have a range of X to Y and the other one would have the
01:30:25.840
It seems to be a problem that is set up perfectly for some type of machine learning because everything
01:30:33.660
you said is correct. And then as you also alluded to, there's another layer here, which is we know
01:30:40.280
quite a bit about the epidemiology. All things equal, a 40-year-old without a single pre-existing
01:30:45.540
condition, you're going to weigh that input differently than a 60-year-old with no pre-existing
01:30:51.820
conditions or a 40-year-old with type 2 diabetes versus a 60-year... They all have a very different
01:30:57.360
physiologic age, even if their chronologic ages are similar. And so when you start to factor in
01:31:02.820
that, plus some of these signatures, plus the temporal nature of the signature, when am I getting
01:31:09.700
this? I think there is an amazing opportunity for information and data scientists to help prepare
01:31:16.860
us for how we will think about this when it happens the next time.
01:31:19.680
Yeah. And so what you need out of this is you need, as we've talked about for some of the projects
01:31:25.420
we've talked about, what you'd ideally like to do is you'd like to take people, sample them every
01:31:30.260
couple of days, see what their numbers look like, put them in this machine learning model that you're
01:31:36.120
talking about. And then if you had enough money so you can measure all these different cytokines,
01:31:40.700
you might say, okay, this person has this block of markers that say he's going to get sick,
01:31:45.600
whether it be the 40-year-old, because the 40-year-old can get sick, or whether it be an
01:31:49.780
older person. And you put the other point you make about the epidemiology on top of that,
01:31:55.440
and maybe you would not even bother testing the 40-year-old because the odds of his getting sicker
01:32:00.260
and meriting all the cost and use of resource is not worth it. We're not there yet in terms of
01:32:05.660
thinking about which markers are best. And also, how do you actually do this? How do you actually do a
01:32:11.520
study where you can help a person by getting serial testing and seeing which way he or she
01:32:16.260
is going in terms of disease? But that would be the ideal way, because that person, if you saw
01:32:21.200
signs of things going badly, maybe that's the person you'd use either remdesivir or hopefully
01:32:26.260
an oral form of remdesivir, stop the virus in its tracks, maybe give an immune activator. Again,
01:32:33.640
unclear, I think if you give an immune activator to some people, it'll be deleterious,
01:32:37.800
so it has to be done so carefully. There are two last topics I want to get to,
01:32:42.400
one being how we would study the durability of immune response, which is effectively the most
01:32:48.540
jugular question out there today. I mean, if we're going to think about this through the lens of
01:32:53.700
vaccination, and we're going to think about this through the lens of herd immunity, natural or
01:32:57.380
otherwise, we better figure out exactly what's going to happen to these people who get infected
01:33:01.960
and what superpowers they do or don't have in the future. Before I do that, though,
01:33:06.340
I want to go back to one thing we kind of alluded to very briefly, and then skipped ahead, which was
01:33:11.200
that paper that came out kind of recently. Matt Ridley is the journalist who wrote about it,
01:33:15.580
I think in the Wall Street Journal, but he refers to the paper by Zahn that came out, I think in
01:33:19.740
April, that argued basically, the virus may not have come from the wet market the way we think it does.
01:33:28.020
I know that we've been sending each other so many papers back and forth over the last few weeks.
01:33:33.080
I think so. It's the one that says, there's a bunch of these, so I'm not sure I have the
01:33:38.480
Ridley one in mind. The one that says it was released accidentally from the Wuhan lab, or the one
01:33:44.420
that says it was- No, the one that said it was basically so genetically stable, it was really, it's
01:33:50.220
mostly a person-to-person transmission. So I think it basically said, look, this is mostly a person-to-person
01:33:55.380
transmission. And I think it said, if it came out of animals, it was so long ago that we don't know
01:34:01.080
about it. It basically argues that the narrative that this came from an animal source to a human
01:34:07.220
source in somewhere between October, November, December of last year is not correct. Had you seen this
01:34:14.640
Okay. All right. We won't dive into that too much.
01:34:17.280
The point is well taken that it is remarkably fit for humans. I don't know about the first part of the
01:34:23.020
conclusion, you know, that it came out earlier, but it is remarkably fit.
01:34:26.720
Yeah. I mean, I think they basically looked at the amount of genetic drift that occurred and said,
01:34:31.780
it's, I read it, I think four weeks ago. So I'm a little rusty on it, other than a few notes I took
01:34:36.580
that were somewhat cryptic. But I think the argument was, look, this has probably been in
01:34:39.760
humans longer than we think. I'll re-forward it to you after just for the purpose of pure interest.
01:34:45.080
So how do we figure out how long people are going to, because it might not be that interesting how much
01:34:50.200
immunity people have to regular common cold coronavirus, but it's going to be pretty darn interesting to know
01:34:55.220
how long people are going to have immunity to this virus. I mean, we've already at a minimum
01:34:59.940
seen close to 10 million people infected worldwide with this virus. Personally, I think that's a gross
01:35:07.320
underestimate of how many people have been affected. I think it's probably closer to 100 million people
01:35:13.380
have been infected. But regardless, the durability of their immune response has to be one of the most
01:35:20.900
important questions we understand. How would we do that? Yeah, so just doing the things we're doing.
01:35:26.480
People who are infected, measuring their antibody responses, if we can measuring their T cell responses.
01:35:31.980
The odds are that we're going to see waning immunity for people at mild disease. That's who we're
01:35:36.680
hearing over and over again. And that's what's been true for other coronavirus infections.
01:35:40.740
And what will the implication of that be? Will the implication then be that no matter how successful
01:35:45.800
a vaccine is, it's going to need to be an annual vaccine? There's two goals. One is to protect the
01:35:51.360
individual who's vaccinated from getting severe pneumonia. And that may actually occur already.
01:35:57.960
So that may be whether immunity wanes or not, that person may never get severe pneumonia. The other issue
01:36:03.900
which is equally important is how much immunity do you need to prevent shedding, to prevent
01:36:09.080
transmissibility to other people. And that's the one that I think is really unknown and to me is more
01:36:14.920
important. Not important to the individual, but to society. To me, that's the jugular question that
01:36:20.420
decides what do economies look like when we have subsequent waves of this? Because I did something
01:36:25.760
on Instagram a few weeks ago where I did a kind of Q&A with my son who's five. And he asked a very
01:36:31.640
honest question, which is when is this virus going to be gone? And it was an interesting discussion to
01:36:36.120
explain to him, actually, it's never going to be gone. This virus is never going away. There is
01:36:41.740
nothing about this virus that suggests it's ever going away. And so now the question is how do we
01:36:46.500
coexist with this virus? So even putting aside future pandemics, which could be much worse,
01:36:53.620
for example, an increase in the lethality while preserving the transmissibility of SARS-CoV-2
01:36:59.600
would be devastating. But just coping with this, if another one never shows up,
01:37:05.280
we have to understand this question, especially if the vaccines are somewhat risky. One thing that
01:37:11.740
doesn't get a lot of discussion is how much risk is going to be posed by vaccines. There's a reason
01:37:17.340
they never come up with RSV vaccines. It's a lot harder from a safe perspective to make an RSV
01:37:23.420
vaccine, unlike an influenza vaccine. So if everything is going to be a risk trade-off, right? And we're
01:37:29.400
going to decide you might not want to vaccinate everybody with a SARS-CoV-2 vaccine if the risk
01:37:35.320
is slightly higher than we deem acceptable. So then you have to do a cost benefit analysis. And then to
01:37:41.240
your point, which I think is even more important is, okay, what does the secondary shedding look like?
01:37:46.420
What do these other factors look like? It's hard for me to imagine a world that's fully functioning
01:37:51.340
without these questions resolved. Right. That's really the key question. The other hand,
01:37:55.980
though, if you get to a point where there's enough herd immunity or that a hundred million
01:38:00.740
turns into a six billion, people have seen the infection. So nobody gets pneumonia anymore. It
01:38:06.940
turns into a common cold. Then there may be enough of a balance between the virus mutating a little to
01:38:13.640
become a better common cold and no longer causing the pneumonia. But that's the point. It requires a
01:38:20.020
mutation, doesn't it, Stanley? Yeah, yeah, yeah. We don't have the memory like we do with measles
01:38:25.900
and polio and smallpox to truly generate herd immunity. In fact, we've never generated herd
01:38:30.760
immunity to influenza commonly. In that case, of course, it's because of the genetic drift. And so
01:38:35.520
isn't it a bit of a misnomer to suggest that we could ever have herd immunity to SARS-CoV-2,
01:38:42.060
let's just say, if we knew that the immune response was gone after a year?
01:38:45.880
The question is, what is the immune response being gone?
01:38:48.960
Yeah, a sufficient immune response. I mean, it becomes a sliding scale of efficacy, correct?
01:38:53.220
Yeah, yeah, yeah. That's right. But if you have enough immune response to protect you from
01:38:58.400
pneumonia, then the question is, how much shedding do you have? When we talk about studies, I was
01:39:04.780
thinking about this a little while ago. The simplest study would be to take some human volunteers,
01:39:10.340
give them a common cold coronavirus, and then a year later, come back and do the exact experiment
01:39:15.800
that was done in the 80s, measure, do they get a cold? If you reinfect them a year later,
01:39:20.760
do they get a cold? And how much shedding do they have? We know they shed, but if you are a
01:39:25.460
naive person with a cold, you shed 10 to the 8th, and now you shed 10 to the 3rd, and it doesn't
01:39:30.180
matter. Yeah, then it doesn't matter. Yeah. Well, and of course here, so again, I completely agree
01:39:34.960
with you that that's the single most important question. But the other thing is, I don't have
01:39:40.000
my fingers crossed that this is perfect because of that upper respiratory part of this. So you said,
01:39:44.520
well, what if you don't get the severe pneumonia before? Well, it turns out the severe pneumonia
01:39:48.700
that came with SARS-1 and MERS isn't really what was the problem. I mean, that was the problem for
01:39:53.960
the individual, but that was not the problem for society. The problem for society was the upper
01:39:58.260
respiratory part. That's what we're seeing in SARS, or the lack thereof. And that might be what's
01:40:03.600
making SARS-CoV-2 such a problem. Yeah, that's right. Anyway, Stanley, as you can tell, we can talk
01:40:09.020
about this for days, but I want to honor our commitment to get you out of here in a certain time.
01:40:13.780
So I look forward to talking with you again very soon as we continue to work on the project we're
01:40:18.140
working on with David and a group of other really amazing people. But thank you for your time and
01:40:23.660
your generosity of insight. Anything else, any last thoughts you have on either this particular
01:40:28.080
pandemic or just coronaviruses in general? No, I think the key thing we talked about is
01:40:32.860
how do you prevent this in the future? We're going to muddle our way through this one. We're going to do,
01:40:37.520
we'll get to points, I think, where we'll have antivirals, I hope. Vaccines, even with the
01:40:42.980
caveats that we talked about that should work. How long they'll work, I don't know. Whether people
01:40:47.880
actually agree to be vaccinated is another issue we didn't really talk about. And then for safety,
01:40:53.660
I mean, all these things we're going to know very quickly because we have to do it quickly.
01:40:58.060
Well, that means we're going to have to talk again.
01:41:04.780
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