Speaker 1: Pushkin from Pushkin Industries. This is deep background to show
Speaker 1: where we explore the stories behind the stories in the news.
Speaker 1: I'm Noah Feldman. For more than a year we've been
Speaker 1: hearing about the idea of herd immunity. In recent weeks, though,
Speaker 1: it's become very clear that the United States is not
Speaker 1: in the foreseeable future going to reach the threshold for
Speaker 1: herd immunity. There are a range of reasons and causes
Speaker 1: for this, and they go from vaccine hesitancy, to the
Speaker 1: contagiousness of new variants, and beyond to the underlying science.
Speaker 1: As a consequence, we're all trying to figure out what
Speaker 1: this means for what happens next. Will COVID become a manageable,
Speaker 1: self contained disease not unlike the common coal, Will it
Speaker 1: alternatively develop new variants that require us to go back
Speaker 1: to the drawing board and develop new vaccines, or will
Speaker 1: it be something in between. To help us understand these
Speaker 1: pressing questions, we're joined by doctor Mark Lipsitch Our go
Speaker 1: to COVID expert here on the program and indeed throughout
Speaker 1: the country. Mark is a professor of epidemiology at the
Speaker 1: Harvard Shan School of public Health. He's affiliated both with
Speaker 1: the Epidemiology Department and with the Department of Immunology and
Speaker 1: Infectious Disease. He runs the Center for Communicable Disease Dynamics
Speaker 1: at Harvard. Regular listeners of the podcast will know that
Speaker 1: Mark was one of the first voices anywhere in the
Speaker 1: United States or indeed in the world, drawing attention to
Speaker 1: the future trajectory of COVID nineteen. He joined us as
Speaker 1: early as February twenty twenty to tell us where the
Speaker 1: disease was going to go, and he's managed to join
Speaker 1: us intermittently ever since, taking time out of his extraordinarily
Speaker 1: busy schedule to set us right about where COVID is,
Speaker 1: where it's been, and where it's going. Mark, thank you
Speaker 1: as always for joining us. In general, I've tried to
Speaker 1: keep you as a guest, reserved for those moments when
Speaker 1: something really important seems to be shifting in the trajectory
Speaker 1: of COVID nineteen and news reports suggest that maybe we're
Speaker 1: getting there at this moment as well, and that that's
Speaker 1: something has to do with our acknowledgement finally that herd
Speaker 1: immunity may not be coming our way in the United
Speaker 1: States and the feseable future. It's something you have been
Speaker 1: warning about really almost from the start. So I want
Speaker 1: to start by just asking you to remind us, all
Speaker 1: for definitional purposes, of what herd immunity is defined in
Speaker 1: terms of our zero the replication rate of the virus. Sure,
Speaker 1: I think what you're asking is about the herd immunity threshold,
Speaker 1: and I'll come back to that distinction in a minute,
Speaker 1: because I think it's actually helpful to talk about it,
Speaker 1: But because the herd immunity threshold is to find as
Speaker 1: that level of immunity in the population from whatever means,
Speaker 1: usually infection or prior infection or vaccination or a combination,
Speaker 1: that it can't spread widely because there are so many
Speaker 1: immune people that chains of transmission don't sustain themselves and
Speaker 1: they fizzle out before the virus can spread too far.
Speaker 1: That is quantified by the basic reproductive rate or basic
Speaker 1: reproductive number are zero are not, which is the number
Speaker 1: of secondary cases that each case creates, and when everyone
Speaker 1: is susceptible, and when you do a little bit of
Speaker 1: algebra with that expression and try to find a level
Speaker 1: of immunity where instead of infecting, say three or four
Speaker 1: other people, the average case infects less than one other person,
Speaker 1: meaning the number of cases is going to go down
Speaker 1: over time. If you do the math, you end up
Speaker 1: getting the proportion that have to be immune is one
Speaker 1: the reciprocal of that number our zero one one over
Speaker 1: our zero. And so, to give some examples, if our
Speaker 1: zero is three, then that's two thirds. If our zero
Speaker 1: is four, that's three quarters. You've been saying ever since
Speaker 1: people started talking about the possibility of herd immunity being
Speaker 1: created partly through the spread of vaccines, that it would
Speaker 1: be optimistic. I think that's the word you used to
Speaker 1: actually imagine we could get there. As I understand some
Speaker 1: public statements that you've made recently, including the New York Times,
Speaker 1: you're now willing to shift a little bit from it's
Speaker 1: unlikely that we'll get there, too. It seems extraordinarily improbable
Speaker 1: that we're going to get there in the foreseeable future
Speaker 1: in the US, at least not through vaccinations as opposed
Speaker 1: to vaccinations plus natural infections. What has shifted your empirical observation.
Speaker 1: I don't think your theory has changed, but what has
Speaker 1: caused your perical observation to evolve to that point? Well,
Speaker 1: I think I do want to now mention the concept
Speaker 1: that hurt immunity and that threshold are slightly different. The
Speaker 1: threshold is the point where there is so much hurt
Speaker 1: immunity that we don't have ongoing transmission when we return
Speaker 1: to normal behavior. Herd immunity is a quantity, it's between
Speaker 1: zero and one, and we are getting more and more
Speaker 1: of it, So we are getting hurt some hurt immunity.
Speaker 1: But my statements have been about whether we're going to
Speaker 1: reach a level of immunity that means that we can
Speaker 1: expect zero or nearly zero transmission despite pre pandemic types
Speaker 1: of behavior. So, first of all, thanks for that clarification,
Speaker 1: because I and I think most other non scientists have
Speaker 1: been using the term herd immunity when what we should
Speaker 1: have been saying is the threshold of enough hurt immunity.
Speaker 1: So you could say, well, right, it's like the blueness
Speaker 1: of the blue thing. It could be very faintly blue
Speaker 1: and it would still be blue. But the question is
Speaker 1: how blued you need it to be for whatever your
Speaker 1: purpose is. Right, Okay, that's important. That's important for I mean,
Speaker 1: everybody is, including scientists, are sometimes sloppy about using her
Speaker 1: immunity is shorthand for the threshold. The reason I try
Speaker 1: to be very careful about it is that herd immunity
Speaker 1: is a good thing. Even a little bit is good,
Speaker 1: and a little more is a little better. And being
Speaker 1: below the threshold does not mean it's not doing any work.
Speaker 1: It is doing a lot of work. So that's actually
Speaker 1: some of the good news is that we are building
Speaker 1: up a lot of herd immunity. And the reason to
Speaker 1: answer now your question, the reason why I think it's
Speaker 1: extremely unlikely that we will get to the threshold in
Speaker 1: the United States is a few things. One is, when
Speaker 1: we started out, we had no data on whether these
Speaker 1: vaccines were protective against infection and a transmission, and that's
Speaker 1: the part of vaccine effectiveness that matters to her immunity.
Speaker 1: If everybody gets a technis shot, that doesn't protect the
Speaker 1: next person from getting tetanus because it doesn't do anything
Speaker 1: to transmission of the bacteria which comes from the soil.
Speaker 1: If the vaccine isn't stopping transmission, then but it's just
Speaker 1: stopping disease, it's not doing anything for her immunity. These
Speaker 1: vaccines do a lot for her immunity. Initially, it was
Speaker 1: unclear how much the first number I think that was
Speaker 1: meaningful that came out with sixty one percent, but that
Speaker 1: was from one dose and probably an underestimate for technical
Speaker 1: reasons that aren't that interesting for the Maderna vaccine, And
Speaker 1: now the numbers have come out through various sources of evidence.
Speaker 1: It's still uncertain, but it seems like it's probably somewhere
Speaker 1: between about sixty and ninety percent, probably seventy and nine
Speaker 1: protective against the process of transmission. So that's really good news,
Speaker 1: but it's not one hundred percent. And that distinction matters
Speaker 1: because to get to the herd immunity threshold, we have
Speaker 1: to cut transmission to one minus one over our zero,
Speaker 1: not just vaccinate that number of people. So the more
Speaker 1: the closer to one hundred percent effect of the vaccine is,
Speaker 1: the more we can interchange how many people have been
Speaker 1: vaccinated and how many people are totally immune. But we
Speaker 1: can't totally do that yet. It's because we have to
Speaker 1: multiply one by the other. Right, the question is not
Speaker 1: how many people have the vaccine, and it's not how
Speaker 1: much does the vaccine do, it's how much does the
Speaker 1: vaccine do for the number of people who have been
Speaker 1: vaccinated exactly. Yeah, okay, so we now understand that number,
Speaker 1: and though it's surprisingly good seventy nine, it's still not
Speaker 1: going to get us necessarily where we need to go
Speaker 1: when you consider it as a percentage of all of
Speaker 1: the people who've been vaccinated, which is the part that's
Speaker 1: not so high. Right. So the other bit of good
Speaker 1: news that makes it easier to get close to the
Speaker 1: threshold is that children really don't seem to be as
Speaker 1: important for transmission, and so that one one over our
Speaker 1: zero is an average. And as you learn more about
Speaker 1: the population, if you leave out some of the people
Speaker 1: from vaccination who are less important to transmission, that matters
Speaker 1: less than leaving out people who are more important to transmission.
Speaker 1: So that probably buys us a little bit of margin.
Speaker 1: How far did those numbers go mark on kids not
Speaker 1: being involved in transmission? And the reason this is relevant
Speaker 1: is one of the conversations that I've heard repeated a
Speaker 1: lot among all kinds of people is people say, well,
Speaker 1: I'm vaccinated, but my kids aren't vaccinated, and so I'm
Speaker 1: worried that there is some possibility that I might transmit
Speaker 1: to them, or that they might transmit to me, and
Speaker 1: even though they wouldn't get that sick, most probably they
Speaker 1: would nevertheless transmit it. And so if the number of
Speaker 1: kids not transmitting is relatively high, then that worry is
Speaker 1: much less salient. It seems to increase with age, So
Speaker 1: a fifteen year old is probably effectively an adult from
Speaker 1: sars Kovi two's perspective, roughly speaking, and a five year
Speaker 1: old is definitely considerably less I'd say that's the sort
Speaker 1: of rough picture. Okay, So those are the bits of
Speaker 1: good news. Mostly, the bits of bad news that make
Speaker 1: it unlikely that, say, the United States will quickly get
Speaker 1: to the herd immunity threshold are First, that variants are
Speaker 1: more contagious than the original strain of sars Kobe two.
Speaker 1: So everyone agreed pretty much that the original strain had
Speaker 1: a reproductive number of about two and a half or three.
Speaker 1: I think that might have been too simple, and maybe
Speaker 1: it's higher in some places, but let's say for the
Speaker 1: sake of argument, it was two and a half or three.
Speaker 1: The B one one seven variant that's now very common
Speaker 1: in many parts of the world is thought to be
Speaker 1: about fifty percent more contagious, more transmissible, so that pushes
Speaker 1: it up to maybe four and a half, and so
Speaker 1: that pushes the herd immunity threshold close to eighty percent.
Speaker 1: So that means that say we need say it's seventy
Speaker 1: five percent, say we need to immunize seventy five percent
Speaker 1: of the population, and say that the vaccine is eighty
Speaker 1: percent of transmission, then we need to get very close
Speaker 1: to whatever seventy five divided by eighty is, so very
Speaker 1: close to one hundred percent coverage in the population in
Speaker 1: order to reach that threshold. And given the combination of
Speaker 1: hesitancy poor access, which I think are two sides of
Speaker 1: the same coin, and so far not vaccinating children under sixteen,
Speaker 1: soon it will probably be under twelve, I think it's
Speaker 1: just very hard to imagine getting to that level. So
Speaker 1: now let's turn to what this means in practical terms.
Speaker 1: There are a few different dimensions. Let's start by thinking
Speaker 1: about modeling, which is one of the things that you
Speaker 1: do for a living and that you've done so skillfully
Speaker 1: in this entire epidemic process. When you think about what
Speaker 1: models might look plausible for how the current COVID virus
Speaker 1: is going to proceed. Circumstances where we're not at the
Speaker 1: threshold of herd immunity. What's the modeling space, as it were,
Speaker 1: What are the possibilities that you see as most plausible. Yeah,
Speaker 1: I think the most plausible scenario, not the only plausible one,
Speaker 1: but really the most plausible one is one that was
Speaker 1: described in science in a paper by Rustamantia and Jenny
Speaker 1: Levine and Autar Bjornstad. And what they do is essentially
Speaker 1: make an analogy to other coronaviruses. So the most important
Speaker 1: difference probably between this coronavirus and other ones is that
Speaker 1: everyone in the world has been infected with the other
Speaker 1: coronaviruses many times by the time they're say a teenager,
Speaker 1: and so people get infected over and over and it
Speaker 1: just circulates. They just circulate. And those are mostly they're
Speaker 1: not all of the common cold viruses, but they are
Speaker 1: within the family of the common cold viruses. They are
Speaker 1: justifiably obscure except virologists because they don't make people very sick.
Speaker 1: And so I think a very likely outcome is that
Speaker 1: this one behaves similarly, and that what vaccines are going
Speaker 1: to do for us is to get us over the
Speaker 1: hump of the period in history, namely the one we're
Speaker 1: living through where there are a lot of people who
Speaker 1: would get very sick from a first exposure to this virus,
Speaker 1: and everybody's getting first exposures because it's a new virus,
Speaker 1: and therefore that's a bad combination. So if the vaccines
Speaker 1: can be used to put us in a position where
Speaker 1: nobody is getting or a few people are getting exposed
Speaker 1: for the first time when they are also old or
Speaker 1: have comorbid conditions, then the vaccines will have prevented a
Speaker 1: lot of illness and death. And then it's quite possible
Speaker 1: that the residual circulation of the virus among the people
Speaker 1: who aren't vaccinated, or among the people in whom the
Speaker 1: vaccine immunity slowly wanes, is going to give us longer
Speaker 1: term protection against severe disease, so that five years from now,
Speaker 1: you and I and our children and our parents will
Speaker 1: have probably been infected by the coronavirus if we don't
Speaker 1: continue to vaccinate very heavily for the next five years,
Speaker 1: but it won't bother us because we will have all
Speaker 1: been vaccinated once and or had it before at an
Speaker 1: age when we were not likely to get very sick,
Speaker 1: and so it will behave much like the other coronaviruses.
Speaker 1: So the good news part of that is that at
Speaker 1: least over time, that describes a kind of normalization where
Speaker 1: childhood infection is protective in a lot of good and
Speaker 1: healthy ways. I assume the downside of that is that
Speaker 1: among those who are not vaccinated and who are more vulnerable,
Speaker 1: a substantial number of people who have not been vaccinated.
Speaker 1: Among that class of people could get very sick and
Speaker 1: even die in the next let's say five who would
Speaker 1: not if they were vaccinated. Right, So the public health
Speaker 1: goal if that scenario is going to play out, is
Speaker 1: to vaccinate as many of the people known to be
Speaker 1: at high risk as possible, and probably also as many
Speaker 1: of the other people as possible, in order to slow
Speaker 1: down transmission and just give people's immune systems a chance
Speaker 1: to catch up. If that scenario plays out, then the
Speaker 1: vaccines are sort of a bridge to a more peaceful
Speaker 1: future rather than something we have to do all the time.
Speaker 1: So that's the vaccine as bridge scenario. And it's not
Speaker 1: so bad relative to the other possibilities, and you think
Speaker 1: it's the most probable, So that's good news. Talk to
Speaker 1: us about some of the other possibilities. Well, the other
Speaker 1: possibilities would be that immunity to severe disease from the
Speaker 1: vaccine and or from natural infection is not long lasting,
Speaker 1: either because the immunefectors wan over time, or because the
Speaker 1: virus changes and is not as strongly affected by the immunity,
Speaker 1: or both, And so then it's a sort of more
Speaker 1: ongoing war because we have to keep trying to protect
Speaker 1: people from infection, not only from their first infection, but
Speaker 1: from their second, third, fourth infections. And is possible. I
Speaker 1: think infection immunity very likely will wane, But the question
Speaker 1: is whether there is this long term, relatively long term
Speaker 1: immunity that gets you from infection to infection and then
Speaker 1: gets boosted again against getting really sick. So that's one
Speaker 1: of the two subpossibilies that you just describe, that infection
Speaker 1: immunity itself WANs, whether from natural infection or from the vaccine,
Speaker 1: and as you say, whether that's a disaster or not
Speaker 1: really depends on whether the virus is circulating in enough
Speaker 1: quantity that you can get a natural booster from being exposed.
Speaker 1: Then there's the possibility that you mentioned that there might
Speaker 1: actually be an evolutionary process in which the virus evolves
Speaker 1: to the point where it is vaccine resistant. And I
Speaker 1: guess what I want to ask you about is you've
Speaker 1: done plenty of modeling of other viruses that have evolved
Speaker 1: to be vaccine resistant, presumably, and there are lots of
Speaker 1: bacteria where this has happened over time where there's pretty
Speaker 1: good data I think on trying to figure out that,
Speaker 1: and so there must be familiar and available models to
Speaker 1: you when you think about vaccine resistance. Is there any
Speaker 1: way to think intelligently about the probability of something like
Speaker 1: that happening? Yeah, I mean flu certainly is the sort
Speaker 1: of classic example of a viral infection that changes over
Speaker 1: time to resist our natural immunity, and at the same
Speaker 1: time it happens to also escape from existing vaccines, and
Speaker 1: that's why we keep changing the flu vaccine. So I
Speaker 1: think that's the example or the analog. The viruses are
Speaker 1: different and they evolve differently, and I'm not sure how
Speaker 1: to put a probability a sort of how far the virus,
Speaker 1: this virus can go in escaping our immunity. It's like
Speaker 1: we've chased it down an alley, and the question is
Speaker 1: at the end of that alley, is there a brick wall,
Speaker 1: and it's stuck and we've got it. It's escaped as
Speaker 1: far as it can escape, and now there's nowhere more
Speaker 1: for it to go, or is there a big vista
Speaker 1: of other things for it to do? And I don't
Speaker 1: I don't know any way to put probabilities on that.
Speaker 1: I think the best way to know it probably would
Speaker 1: be to try to do it in the lab and
Speaker 1: see where it goes from the variance we've already seen,
Speaker 1: which is itself a somewhat dangerous thing to do, but
Speaker 1: probably a very valuable one. That's a fascinating topic, which
Speaker 1: I would like to come to in just a second,
Speaker 1: but before we do, I'm sort of surprised to hear
Speaker 1: you say that there isn't a kind of ability to
Speaker 1: make a prediction about probability of evolution, especially in light
Speaker 1: of the fact that we've now observed the virus evolving
Speaker 1: pretty quickly with respect to the variants that are out there.
Speaker 1: I mean, is there no I guess there isn't a
Speaker 1: really way to extrapolate from the virus's capacity to evolve,
Speaker 1: to evolve these new variants that are more capable of
Speaker 1: infection than the kind before. To extrapolate from that to
Speaker 1: whether it would be able to evolve in ways that
Speaker 1: would escape the vaccine, Well, I think there are a
Speaker 1: few things. One is, it can mutate. I mean it's
Speaker 1: generating mutations all the time, and the existing variants are
Speaker 1: generating new variants that are more different from the original
Speaker 1: strain than the say B one one seven itself. So
Speaker 1: B one one seven is making new versions of itself
Speaker 1: that are further mutated. So that's not in doubt. That's
Speaker 1: just RNA viruses do that. The question is what will
Speaker 1: the impact be on escaping our immune responses, and even
Speaker 1: for the existing variants, that remains a little bit unclear.
Speaker 1: It is very clear that they escape neutralizing antibodies to
Speaker 1: varying degrees depending on the variant you're talking about. But
Speaker 1: whether that means that they totally escape our ability to
Speaker 1: control them. That's mostly unobserved and still being documented. So
Speaker 1: they can change, that's not in doubt. But whether they
Speaker 1: can change in ways that really get around to a
Speaker 1: large degree, our ability to fight them off with our
Speaker 1: antibodies and other forms of immunity, I think is still
Speaker 1: an open question. Even for the existing to maybe one
Speaker 1: three five one the South African variant or the Brazilian
Speaker 1: variant or the Indian variant. So that's a question. It's
Speaker 1: not whether they can evolve, it's whether how far can
Speaker 1: they go in their biological properties, And that's something that
Speaker 1: you can't really answer, mostly because evolution is not a
Speaker 1: perfectly modelable process, right, I mean, it has contingent features,
Speaker 1: and you know there aren't necessarily absolute is that will
Speaker 1: tell you in relation to both the underlying biology and
Speaker 1: then the way it interacts with the world outside what's
Speaker 1: going to happen. If it were, we could do a
Speaker 1: lot more predictive work on evolution than we actually are
Speaker 1: able to do. Yeah. Yeah, I mean there are a
Speaker 1: number of us, including our group with bacteria, trying to
Speaker 1: chip away at this problem. But this is a major
Speaker 1: hard problem in biology, and we aren't there yet. We
Speaker 1: don't know what the space of possibilities is and how
Speaker 1: it relates to the sequence. Talk to me about what
Speaker 1: in the real world it would look like in this
Speaker 1: scenario where let's call it the flu like scenario. If
Speaker 1: we started with the vaccines as a bridge, this is
Speaker 1: the flu like scenario where we have to go back
Speaker 1: and try to get a new vaccine each time a
Speaker 1: dangerous new variant emerges. Why do we do as poorly
Speaker 1: as we do with respect to the flu vaccine, which
Speaker 1: I guess only prevents about forty to sixty percent of
Speaker 1: the flu each time it's redvised. Yeah, it's a good question.
Speaker 1: I think that in itself is a scientific discussion that
Speaker 1: isn't totally resolved. Why the flu vaccines have been so
Speaker 1: hard to make as good as say, these existing coronavirus vaccines.
Speaker 1: Partly it's about predicting which sequence to use, but even
Speaker 1: when it's well matched, it's not always very good. So
Speaker 1: I think there's some reason for optimism here that the
Speaker 1: first guests at what to do about a coronavirus vaccine
Speaker 1: turned out to be as much as ninety five percent effective,
Speaker 1: and that's much better than flu vaccines. So it may
Speaker 1: be that coronaviruses are easier. But this coronavirus may continue
Speaker 1: to change, And then again, the question is whether it
Speaker 1: changes in a way that evads our infection immunity, which
Speaker 1: would mean that we have to consider trying to control it,
Speaker 1: or whether it evades our severe disease immunity, which would
Speaker 1: be a much bigger deal. And what I mean by
Speaker 1: that is if we didn't have flu vaccines, as most
Speaker 1: of the world doesn't use flu vaccines, there are people,
Speaker 1: many people who die because they don't get flu vaccines,
Speaker 1: but it is not the same kind of global catastrophe
Speaker 1: as this has been. And that's because existing immunity to flu,
Speaker 1: even though the flu viruses are changing, is still protecting
Speaker 1: people to a large degree against getting very sick and dying.
Speaker 1: So the sort of flu analogy is a worse scenario,
Speaker 1: and we probably would try to make better vaccines that
Speaker 1: keep up with the new strains, but it's still not
Speaker 1: a new pandemic every year. It's in the realm of
Speaker 1: public health problem rather than public health catastrophe. We'll be
Speaker 1: right back mark. When you see the virus running maybe
Speaker 1: checked is the wrong word, but running hard and fast
Speaker 1: through a population, as seems to be happening right now
Speaker 1: in India, Apart from the understandable concern about the human
Speaker 1: suffering that that's going to entail, do you think to yourself, oh, boy,
Speaker 1: that raises the probability of new variance emerging that could
Speaker 1: be ultimately vaccine resistant, or do you think, rather, look,
Speaker 1: this is what the virus was always going to do.
Speaker 1: If not restrained and people are catching it, and so
Speaker 1: there's no particular reason to think that it would need
Speaker 1: to evolve new forms of resistance, because, after all, it's
Speaker 1: spreading successfully through the population with whichever variant that it
Speaker 1: presently has. Yeah, I mean, I think it's a fairly
Speaker 1: central principle of evolution that large populations give rise to
Speaker 1: more variation and select the most fit variants more effectively
Speaker 1: than small populations. And in infections, that means lots of
Speaker 1: infected people are both more of a breeding ground and
Speaker 1: more of a efficient filter for variants that are good
Speaker 1: at transmitting. So having virus spreading widely in any place
Speaker 1: is not good for any place else, even places that
Speaker 1: have vaccine access, and that is one of many reasons
Speaker 1: why trying to help India to control the virus is
Speaker 1: in the interest of other countries, in addition to being
Speaker 1: the humanitarian thing to do. When you're wearing your public
Speaker 1: health recommendations, hat, what sensible recommendations do you think policy
Speaker 1: regulators should be considering, Leaving aside the question whether they
Speaker 1: can practically be adopted or not for a world where
Speaker 1: the virus seems to be more or less calming down
Speaker 1: in places with relatively higher vaccination rates, while it's simultaneously
Speaker 1: spreading pretty rapidly through places in the world which have
Speaker 1: very low vaccination rates. I mean, what's the picture of
Speaker 1: what kinds of opening are appropriate, in what kinds aren't,
Speaker 1: and can we really sustain and tolerate a world where
Speaker 1: you know, Westerners would be saying, well, in our countries
Speaker 1: where we've got reasonable amount of vaccination, we're more or
Speaker 1: less reopening. But we're urging you India, Brazil, you know,
Speaker 1: we're urging you to engage in serious lockdowns. I mean, so,
Speaker 1: first of all, is that the sensible thing to be
Speaker 1: saying to them? And second of all, is it plausibly
Speaker 1: sustainable to say that, even even if it's true. Wow,
Speaker 1: that's way way above my pay grade. I mean, I
Speaker 1: think in reality, it is the decision of the countries
Speaker 1: what to do, and if we're not forthcoming as a
Speaker 1: global community with aid to blunt the impacts of having
Speaker 1: to close your societies and vaccine doses in the quantities
Speaker 1: that would make them, make the rest of the world
Speaker 1: able to close. Speaking as a sort of citizen and
Speaker 1: someone who's married to a philosopher, I would say that
Speaker 1: seems very unfair to say our public health is at
Speaker 1: risk because of your virus, so why don't you close
Speaker 1: your society down. I think there are many things in
Speaker 1: between neglecting and telling people what to do. But I
Speaker 1: don't think that our desire to keep variants from emerging
Speaker 1: is or should be a very compelling argument to countries
Speaker 1: that are not receiving or able to generate on their
Speaker 1: own the resources to control the virus in a humane way.
Speaker 1: I mean, I don't think it would be framed that way.
Speaker 1: It would be framed as, look, you still have not
Speaker 1: that many people vaccinated, so you should be engaging in
Speaker 1: the same kinds of lockdowns as we were engaged in
Speaker 1: until now. I mean that is presumably the line coupled
Speaker 1: with and by the way, we'll give you more vaccines
Speaker 1: or will enable you to make more vaccines. Yeah, this
Speaker 1: is where I think, as a scientist, I find myself
Speaker 1: at a of a loss because these are not really
Speaker 1: scientific problems. These really are problems of global equity and
Speaker 1: disparate impact, and I think I will pass on trying
Speaker 1: to solve them. Fair enough, I mean, I guess what
Speaker 1: I wanted to say is that they are classically social
Speaker 1: scientific questions in that well, they of course require some
Speaker 1: normative assessment. But that normative assessment, you know, of what
Speaker 1: we ought to do is based a little bit on facts.
Speaker 1: But in any case, I won't press you. Let me
Speaker 1: ask one more question mark before I close by going
Speaker 1: back to your mention of lab experiments, and the question
Speaker 1: is basically this, when you look at where the US
Speaker 1: is now and where it plausibly will be in the
Speaker 1: next six months as we vaccinate twelve to fifteen year olds,
Speaker 1: how much prophylactics shouldn't remain in place in your view?
Speaker 1: I mean, at what point will it be plausible to
Speaker 1: say we no longer need to mask up when we're indoors,
Speaker 1: or we no longer need to maintain social distancing in schools.
Speaker 1: I think that is a great question. I think what's
Speaker 1: going to happen is that we're going to sort of
Speaker 1: feel our way in that direction, and there's going to
Speaker 1: be a lot of variation across any given rich country
Speaker 1: in how fast people go, and we'll get some sense
Speaker 1: from those experiments, those non planned experiments as to what works.
Speaker 1: I mean, in trying to frame how to think about it,
Speaker 1: I would say the goal is that when there are
Speaker 1: very very few people at high risk still in the
Speaker 1: line of the virus and unvaccinated, then permitting more spread
Speaker 1: is a much safer thing to do. It's not totally safe,
Speaker 1: but it becomes a reasonable trade off with the fact
Speaker 1: that we all want to have economic, social, educational, and
Speaker 1: cultural lives back. But to give a number at this stage,
Speaker 1: I'm not really sure. I mean, in some ways, one
Speaker 1: of the more optimistic, the most optimistic information is coming
Speaker 1: out of Israel right now in the sense that they
Speaker 1: have when you talk to people really reopened to a
Speaker 1: striking degree, and their cases continue to go down, and
Speaker 1: their hospitalizations and desks to stay at low levels, and
Speaker 1: they have not gotten anywhere close to what seems to
Speaker 1: be the herd immunity threshold. And so to me, that's
Speaker 1: to go back to our earlier discussion, that might be
Speaker 1: the evidence that some of these concerns are overblown, that
Speaker 1: we can actually control spread with a little bit lower
Speaker 1: levels of vaccination. But what I think is also happening
Speaker 1: in Israel, as I understand it, is that if you're vaccinated,
Speaker 1: you have lots of opportunities to go to the theater
Speaker 1: and to go to crowd indoor events and whatever, and
Speaker 1: if you are unvaccinated, you have fewer of those privileges,
Speaker 1: and or you might well be someone who was in
Speaker 1: a high risk group for infection before and are benefiting
Speaker 1: from natural immunity. So I'm wondering to what extent Israel
Speaker 1: really is an example of reopening, and to what extent
Speaker 1: it's partial reopening. But I think they will set a
Speaker 1: pace that we can sort of watch and see what
Speaker 1: works and what doesn't. Mark before I let you go,
Speaker 1: you made an intriguing comment about the scientific value of
Speaker 1: doing in lab experiments and trying to see what happens
Speaker 1: to COVID nineteen in the lab, And obviously there's a
Speaker 1: lot of nervousness around this, especially given the ongoing belief.
Speaker 1: I don't know if I would call it a paranoid
Speaker 1: fantasy or not. That might be too strong formulation, but
Speaker 1: the ongoing, let's call it unsubstantiated belief among some that
Speaker 1: perhaps COVID nineteen originated itself in a lab and then
Speaker 1: unintentionally escape from that lab. How much could laboratory based,
Speaker 1: responsible careful research reveal and what would make it worth
Speaker 1: doing given the presumably existing risks of an accidental leak
Speaker 1: or outbreak. Well, I think the beliefs on all theories
Speaker 1: are all hypotheses for the origin are unsubstantiated right now,
Speaker 1: And I've said publicly and continue to say that I
Speaker 1: think investigating the Lab league hypothesis is the responsible thing
Speaker 1: to do, as has for example, the head of the
Speaker 1: World Health Organization, the group that put out the report,
Speaker 1: downplaying that theory. That's quite helpful actually, by the way,
Speaker 1: So what I'm reading in code is that people like
Speaker 1: me shouldn't say, oh, that's crazy. It might or might
Speaker 1: not be We don't have the data. Yeah, it's not crazy,
Speaker 1: it might be wrong. But the arguments put out so
Speaker 1: far to say that a LAB leak is way less
Speaker 1: likely than the competing hypothesis I think don't hold any water.
Speaker 1: Very good to hear. Okay, so that's a very helpful corrective.
Speaker 1: But to answer your specific question, I spent much of
Speaker 1: the decade of the twenty tens working very hard in
Speaker 1: the sort of science policy arena on an effort to
Speaker 1: curtail experiments so called gain a function of concern, experiments
Speaker 1: that make at that time it was mostly influenza viruses
Speaker 1: more contagious or more deadly and the basis of that
Speaker 1: concern or of that activity was a calculation of risk
Speaker 1: and benefit that the science doesn't save enough lives in
Speaker 1: expectation to be worth the possibility of creating a novel
Speaker 1: pandemic pathogen that could get out of a lab by
Speaker 1: mistake and spread, not to mention the possibility of fading
Speaker 1: deliberate attempts, the possibility that experiments like dangerous experiments could
Speaker 1: also aid deliberate attempts to misuse biological agents as weapons.
Speaker 1: But I was focused more on the safety aspect. And
Speaker 1: one of the people who was in some ways supportive
Speaker 1: of my efforts and those of my other colleagues was
Speaker 1: Jesse Bloom, who was one of the several groups that
Speaker 1: did experiments with this coronavirus to see what would happen
Speaker 1: when you asked the virus to escape human serum, to
Speaker 1: escape the immunity and human theorem, the antibody immunity and
Speaker 1: human sorem. And what they found was that you generate
Speaker 1: mutations very much the ones that we have been seeing
Speaker 1: in the variants that have become globally famous, for example,
Speaker 1: the four four K mutation. And that was incredibly valuable
Speaker 1: information because it allowed vaccine developers to understand that this
Speaker 1: was not just a freak that happened in one or
Speaker 1: two variants, but was actually the sort of typical thing
Speaker 1: that happens even in a laboratory. And other mutations were
Speaker 1: also identified, so you could ask the question, would it
Speaker 1: be a good idea to now take the existing variants
Speaker 1: that have those mutations and do that again. I would
Speaker 1: very much expect that people are doing those experiments as
Speaker 1: we speak, if they haven't already done them, And in
Speaker 1: this case, I would be supportive of doing that kind
Speaker 1: of potentially dangerous experiment because first, it has a very
Speaker 1: clear public health rationale that it's not just scientific curiosity
Speaker 1: that would be satisfied, but it would help to prepare
Speaker 1: us for vaccination and other countermeasures. And also that we
Speaker 1: have a big problem in front of us. It's not
Speaker 1: that the virus being created there is utterly novel. The
Speaker 1: analog of that experiment is being done in people's body
Speaker 1: these around the world. So I think the incremental risk
Speaker 1: of doing the experiment is smaller and the incremental benefit
Speaker 1: of doing it is greater than those other experiments that
Speaker 1: I was very much against. That's extremely helpful. You've given
Speaker 1: us some good news and some bad news, and as always,
Speaker 1: you're the soul of balance. Can I ask you, if
Speaker 1: you think back to where we were in February of
Speaker 1: twenty twenty, is the overall picture worse than you thought
Speaker 1: it was going to be slightly better than you thought
Speaker 1: it was going to be more or less the same. Well,
Speaker 1: I'll give you a balanced answer. So the part that
Speaker 1: is much better than I think anybody believed was possible
Speaker 1: in February of last year is that we have in
Speaker 1: large parts of the world, though not enough of the world,
Speaker 1: substantial supplies of very effective vaccines. I mean, I saw
Speaker 1: a prediction from April from a university research group that
Speaker 1: said absolute best case scenario as of April last year
Speaker 1: was that we would be beginning around now to start
Speaker 1: rolling out vaccines, and we began rolling out vaccines four
Speaker 1: or five months ahead of that. And the vaccines are
Speaker 1: not just fifty percent effective, which was the floor set
Speaker 1: by the FDA, but up to ninety five percent effective.
Speaker 1: That's all just stunningly good news. And to be fair,
Speaker 1: part of the reason for that good news is that
Speaker 1: the US, Brazil and the UK created a global public
Speaker 1: good by having rampaging epidemics that allowed vaccine trials to
Speaker 1: go quickly, and the whole world has us to thank
Speaker 1: for not controlling our virus very well, with the consequence
Speaker 1: that we were able to get quick answers about how
Speaker 1: well the vaccines worked, So that part, I think is
Speaker 1: much better than expected. I think the speed with which
Speaker 1: variants have come up is a little worse than expected,
Speaker 1: and the fact that they probably do have significant consequences
Speaker 1: for immunity, even if they don't totally defeat it. And
Speaker 1: then the most confusing part is in February, everybody was
Speaker 1: saying that the sorts of disparities we see within rich
Speaker 1: countries where the worst off are hit harder by the virus,
Speaker 1: would be true globally and the sub Sharan Africa, India, etc.
Speaker 1: Basically the global South would be hit much harder and
Speaker 1: it would be a catastrophe. And then that didn't happen
Speaker 1: for the first year or so, and everyone started scratching
Speaker 1: their head trying to understand whether it was a reporting
Speaker 1: artifact or not true, or really was true, and if so, why,
Speaker 1: And now we see South Asia, not just India but
Speaker 1: its neighbors as well, really really struggling under a renewed epidemick,
Speaker 1: and I would say that part is just puzzling and
Speaker 1: sort of gives a real humility to scientists who thought
Speaker 1: we understood what would happen, then it turned out not
Speaker 1: to happen, and now it's turned out to happen a
Speaker 1: year after everybody else, and I just I can't explain it. Mark,
Speaker 1: thank you as always for your clarity, your rationality, your judgment,
Speaker 1: and for putting us in the picture. I'm really grateful
Speaker 1: to you. Thank you. It's nice to talk to us. Ever,
Speaker 1: doctor Mark lipsych is always the reasonable man. He gives
Speaker 1: you the good news as well as the bad news,
Speaker 1: and in this conversation with him, he gave us a
Speaker 1: reasonable dose of each. To start with. His top line
Speaker 1: observation is that we are really not going to reach
Speaker 1: the threshold for her immunity in the United States in
Speaker 1: the foreseeable future. Mark had warned of that possibility, indeed
Speaker 1: that probability over the last year plus, and now he
Speaker 1: says that it's pretty certain that that's the outcome that
Speaker 1: we've reached. What does that mean in practice? Mark lays
Speaker 1: out several scenarios, the first, which he thinks is the
Speaker 1: most likely and is not a bad scenario as these
Speaker 1: things go at all is it. Vaccines function as a
Speaker 1: bridge for us, protecting those people who would be badly
Speaker 1: harmed by a first exposure to the coronavirus, while simultaneously
Speaker 1: allowing young people to be exposed to the virus for
Speaker 1: the first time at an age where it's very very
Speaker 1: unlikely to harm them. As a consequence, we would all
Speaker 1: eventually develop our own immunities to the coronavirus, and over time,
Speaker 1: assuming that we are exposed frequently enough without it harming us,
Speaker 1: COVID nineteen would become very much like other coronaviruses out
Speaker 1: there in the world, but not much remarked because not
Speaker 1: doing anybody very much harm. Yet, Mark also recognizes the
Speaker 1: possibility of another much more worrisome scenario in which either
Speaker 1: the immunity that we get from being exposed to the
Speaker 1: vaccine or to the virus doesn't last very long, or
Speaker 1: still worse, in which the virus mutates and evolves to
Speaker 1: a point where it escapes the vaccines that we have
Speaker 1: for it. In those circumstances, COVID nineteen would start to
Speaker 1: look a lot more like the flu, and as we know,
Speaker 1: our flu vaccines are a bit of a challenge because
Speaker 1: they face a moving target in addressing the flu as
Speaker 1: it evolves each year, and as a result they don't
Speaker 1: successfully suppress the flu. Given that covid can be much
Speaker 1: more harmful than the flu, that is a genuinely worrisome scenario. Ultimately,
Speaker 1: even when I pressed Mark to be a little less balanced,
Speaker 1: he gave us the reasonable balanced analysis that says that
Speaker 1: in certain respects we've done much better in this vaccine
Speaker 1: than anyone could have expected, but in other respects we've
Speaker 1: done really pretty badly, especially with reference to the fairness
Speaker 1: and justice of where the disease has harmed people and
Speaker 1: where it's likely to continue to harm people going forward
Speaker 1: into the future. My main takeaway from listening to Mark
Speaker 1: now and the past is that we have to continue
Speaker 1: to be cautious in thinking about where we're going with
Speaker 1: respect to this disease. We might be seeing the light
Speaker 1: at the end of the tunnel, but we cannot know
Speaker 1: for sure that we are. We might be able to
Speaker 1: say that we're on our way to a return to normal,
Speaker 1: but we still cannot be utterly certain of that. Ongoing
Speaker 1: vigilance is still going to be necessary. The challenge for
Speaker 1: all of us is to live as near to normal
Speaker 1: as we can, as little based on fear as we can,
Speaker 1: while simultaneously being rational about the risks and challenges that
Speaker 1: lie ahead. Until the next time I speak to you,
Speaker 1: I guess I'm afraid we have to continue to be
Speaker 1: a little bit safe, we have to continue to be
Speaker 1: a little bit careful, and I really hope that we
Speaker 1: can all continue to be well. Deep background is brought
Speaker 1: to you by Pushkin Industries. Our producer is Mola Board,
Speaker 1: our engineer is Ben Tolliday, and our showrunner is Sophie
Speaker 1: Crane mckibbon. Editorial support from noahm Osband. Theme music by
Speaker 1: Luis Gara at Pushkin. Thanks to Mia Lobell, Julia Barton,
Speaker 1: Lydia Jeancott, Heather Faine, Carlie Migliori, Maggie Taylor, Eric Sandler,
Speaker 1: and Jacob Weisberg. You can find me on Twitter at
Speaker 1: Noah R. Feldman. I also write a column for Bloomberg Opinion,
Speaker 1: which you can find at Bloomberg dot com slash Feldman.
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Speaker 1: This is deep background