The L.R. Wilson Institute for Canadian History was thrilled to welcome Dr. Nicholas Christakis on 4 November 2021 as a guest speaker in our Syndemic Lecture Series.
IAN MCKAY: welcome everyone, we acknowledge the land on which McMaster university was built it’s the traditional territory of the Haudenosaunee and Anishinaabe Peoples, many of whom continue to live and work here today the territory is covered by the Upper Canada treaties and is within the land protected by the Dish with One Spoon Wampum Agreement. Today this gathering place is home to First Nations, Metis, and Inuit peoples. Thank you so much for joining us this evening for this session of ‘Syndemic,’ our series on the challenges coveted 19 has posed for humanity then please join us on the 15th of July at 7 p.m. eastern daylight time for our last presentation by Chandrima Chakraborty who will address the implications of the pandemic for racialized Canadians our thanks to the future of Canada project and chancellor emeritus L.R. Wilson for their generous support for this series. Nicholas Christakis is one of the world’s most influential and respected interpreters of the Covid 19 crisis. In 2013 Christakis moved from Harvard to Yale University where he is professor in the department of sociology with additional appointments in the department of ecology and evolutionary biology statistics and data science biomedical engineering medicine and in the school of management. In 2018, he was appointed Sterling Professor, the highest honor bestowed on Yale faculty. His third book Blueprint The Evolutionary Origins Of A Good Society (2019) built on his already highly influential interpretation of social networks and made the New York Times bestseller list. This recent study, Apollo’s Arrow, which you see here the profound and enduring impact of coronavirus on the way we live 2020 focused on the pandemic in the US and is sure to stand as one of the most influential interpretations of the recent crisis. In his virtual visit to McMaster Dr. Christakis will present his interpretation of 2021 and will be available afterwards to answer questions.
NICHOLAS CHRISTAKIS: Thank you Ian, yes thank you, I come here, well I come to Canada a lot. For many years we used to summer in Cape Breton in the highland park, and we would – I can’t tell you how many times I’ve been on that little, tiny Port Elizabeth ferry that goes across– and we’ve spent so much time there. And of course, I’ve been to Quebec countless times and Vancouver and Ontario and Toronto. I’ve been to most of the major Canadian cities, so I wish I was there. So, with that introduction, if you want me to proceed I prepared 30 minutes of remarks, which is I’m going to skip a lot of the stuff that’s in the book and I’m just going to put some ideas on the table and then we can have a conversation with the time that’s remaining.
So, all of us happen to be alive during a once in a century event. Something very unusual is happening to us as a species, which is that a new pathogen has been introduced into our midst and this pathogen is going to be with us forever. From the point of view of the pathogen, it is having what is known as an ecological release. It’s like an invasive species, as if we had taken rats to an isolated pacific island and introduced them there and they overran the place. Our bodies are the island to the virus, which is the rat. The rat has found sort of untouched territory in us; we have no natural immunity to this pathogen, and it’s going to spread and spread and spread among us like any other living thing would do. There’s some debate about whether viruses are living or not but for the purposes of this conversation, it’s acting in a in a Darwinian way like any other living thing. And we know quite a bit about the pathogen at this point, although candidly we knew most of these things about the pathogen very early on, by January of 2020. For example, we know that the pathogen is reasonably deadly. It kills between 0.5 and 0.8 percent of the people that it infects. That’s known as the infection fatality rate – the IFR. And if you get symptoms of the disease it’s about twice as deadly; between 1 and 1.6 percent of people who get symptoms of the disease will die. If you were an infectious disease doctor, I was a hospice doctor for many years I took care of people who were dying, so I didn’t often take care of primary infections, but I knew enough to know that it is that an infectious disease that kills one percent of the people in infects is a serious infection, you would not take that lightly. And we also know that [with] this disease now the mortality rate varies by age. If you’re less than 20 and you get an infection, maybe have a one in ten thousand chance of dying; if in your 50s and you get an infection and you have symptoms from it, maybe a one percent chance of dying; if you’re in your 70s or 80s and you get covered you’ve you get symptoms from it you’ve got about a 20 chance of dying that’s a serious infection. And we also know how transmissible how infectious is this disease, so we just discussed its intrinsic lethality but it also has some other intrinsic properties.
One of the other intrinsic properties was its spreadability. its infectiousness. This is quantified by the famous so-called R-naught, the R-sub-zero, or the basic reproduction number and that number for this virus is three. For each case of the virus in a non-immune normally interacting host population, it creates three new cases. and that’s also quite infectious that the seasonal flu for example might have an R-naught of 1.5, barely able to reproduce itself. If you’re infected you infect one other person plus half an extra person and in fact having an R-naught above one is in fact what makes a disease epidemic it rises and rises with time because each case creates more than just itself. Now, if you took these two parameters and you plotted them on a graph for all the respiratory pandemics of the last hundred years; so, in the x-axis you put the severity or the lethality of the condition and on the y-axis the infectiousness. Up here in the upper right you would have the 1918 influenza pandemic which was the most lethal respiratory pandemic we’ve had in the last 100 years and down here in the lower left we would have the 2009 H1N1 pandemic, all of us live through that pandemic probably none of us really think about it or remember it because it wasn’t very lethal. It just gave you the sniffles and in here in the middle you would have the 1957 influenza pandemic which was the second most deadly pandemic we’ve had in the last hundred years until now, and in the United States it killed 110 000 Americans which would be about 220 000 today. So, the Covid 19 however based on these parameters is between 57 and 1918 right here okay and you could have discerned this abinicio like from the beginning back in January, because these parameters were released by Chinese scientists and later in February by Italian scientists so there was nothing surprising at all candidly about what has happened to us.
Since then and one of the reasons I wrote the book is that I was so frustrated – Ian and I were talking about this earlier – I was so frustrated by the awful public discourse we were having about this epidemic, especially on the part of our leaders, who are minimizing the risk, and as it turns out we later learned simply suppressing the evidence that was available. So, this epidemic that we have had is that we’re still in the middle of is quite serious I do not think we are at the beginning of the end of this pandemic, but we are thankfully approaching the end of the beginning at least in North America. Although the rest of the world is going to follow us.
You may have been paying attention to what is happening in some of the more populous regions around the world like in India, in Indonesia, in Brazil, now in sub-Saharan Africa where the epidemic in particular because of these new variants is taking off. And we are once again reading headlines that are astonishing. In India, for example, that the funeral pyres are burning day and night just like on the fields of Troy 3000 years ago when Homer’s Iliad described this kind of event and in fact one of the things that I would say is that while the way we have come to live in the time of covid 19 may feel alien and unnatural, it is it’s actually neither of those things. Plagues are a feature of the human experience. They’re in the bible, they’re in homer, one of the canonical works of Western fiction, one of our oldest extant written things begins with a plague. I mean that’s how the Iliad begins, with a plague in an absolutely magical story which we can talk about if you’re more interested. Or better yet, just re-deal yet it’s a magnificent book. Plagues are in Shakespeare, they’re in Cervantes, they’re in countless pieces of literature in not in the non-Western tradition. So, what happened in 2020 was not new to our species it was just new to us. We thought what was happening was so nuts, so crazy, so unjust, so wrong that we had to endure this, and yet our ancestors have had these experiences. We forget.
We human beings forget and are shocked and yet the irony is that we had an oral tradition not just in literature but also in religion. So many of my Jewish friends during the seder during Passover in 2020 said their whole lives they’ve been doing the Passover Seder talking about the biblical plagues but now it meant felt different as they were as they were saying the Seder. So, our ancestors tried to warn us about this with our oral tradition and we also had a scientific memory among medical historians and historians’ people like Professor McKay, for example, and among epidemiologists. We have like expertise in our society that looks to the past and says, ‘wait a minute something similar is happening right now and yet we had no collective personal memory.’ There were very few people who had personally experienced such a serious epidemic certainly very few people in North America would have this experience.
And this is one of the reasons I think we were caught off guard and one of the other and these plagues unfold in almost a stereotypic way not just epidemiologically but also socially. Let me just illustrate some of this with just some small excerpts and small ideas to put on the table. One of the things that’s important to understand is that the plagues require collective action and often not always state power to respond to you. You cannot fight an invading army alone. If the Canadians were to take up arms and come to the border and invade the United States, my grabbing my gun and going to the frontier would be useless against that, even if every American citizen grabbed their gun and ran to the frontier would also be useless; we would have to coordinate our defense, and this type of coordination that is required reflects the collective nature of the threat that we are facing, that this is a contagious disease that is afflicting all of us at the same time. Many people began to think that what we were doing in response to the virus was collapsing our economy; that it was the state actions like closing schools and closing borders that were the problem, but actually it’s the virus that is the problem. One estimate of the economic impact of the virus in the United States that was executed by Larry Summers, the former treasury secretary, and David Cutler, a former colleague of mine at Harvard also an economist. They call this the 16 trillion-dollar virus; eight trillion dollars in economic damage to our society and eight trillion dollars in loss of life disability illness and so on.
This is a cataclysmic event in the history of our society. It is an economic shock that is almost as great as the Great Depression, and I don’t think people fully appreciate the magnitude of this yet. And many people, as I was saying, wrongly think that it’s our actions or state actions in particular that are causing the problem, but this is not correct. It’s the virus that’s doing it, because this physical distancing and this economic collapse, this slowing down have been features of plagues for thousands of years. For example, during the plague of Justinian, which was a bubonic plague yersinia pestis over 1500 years ago. Historian and priest John of Ephesus had this to say: “and in all ways everything was brought to naught was destroyed and turned into sorrow and buying and selling ceased and the shops with all their worldly riches beyond description and the money lenders large shops (he means the banks) closed the entire city then came to a standstill as if it had perished thus everything ceased and stopped.” Such accounts of the effects of epidemic disease are now eerily familiar aren’t they; an economy involves exchanges, and these depend on social interactions
It’s very hard to have an economy or a functioning society when people are unable to interact, because a germ is spreading that kills them. This is a very stereotypic feature of plagues and there were others too that we revisited. For example, fear, lies and denial have always been companions of plagues for thousands of years. In fact, denial is such a constant feature of epidemics that we might even think of denial as an essential aspect of an epidemic.
In other words, we might even add social factors to our epidemiological definition of what it means to have an epidemic. If you see plague as one of the four horsemen of the apocalypse, mendacity is its squire following right behind it. So, you can look at social networks as my lab has – and today’s talk is not about some of the more sort of mathematical aspects of spreading processes on social graphs that my laboratory studies – but you can mathematically analyze the spread of germs across social connections from me to my friend to my friend’s friends and so on, and right behind it though is misinformation that’s. And this type of superstition and mendacity has been a feature of plagues for thousands of years as incidentally has been denial.
So, when I saw denial rear its head again a year ago as that pandemic was crashing upon our shores at the highest levels of government, for example in the white house but not just there elsewhere as well, I was on the one hand completely dismayed and disappointed but on the other hand completely unsurprised, because denial is a feature of plagues and not just in our leaders frankly in the person on the street. And it’s almost a human response; nobody wants to believe this is happening. We would rather deny and not believe that it’s happening. There’s some scientific work my lab has done if you’re interested in what we call dueling contagions. One of the ways that you can think about epidemics is that there is a biological contagion as the virus spreads from person to person and in parallel to that there are social contagions. For example, of accurate or inaccurate information that’s spreading or of behaviors, for example, mask wearing or vaccination. So, your probability of getting the germ depends on whether your friends have the germ and your friends’ friends have the germ and so on and your probability of putting on a mask as Professor McKay and I were talking about before the lecture depends on whether your friends are wearing a mask or your friend’s friends are wearing a mask. So, you have in this social network you have a biological contagion and in parallel to that you have social contagion and in a sense the question is which one is going to win. Will the social contagion outstrip in some sense the biological contagion?
Plagues are also a time of blame. This is very typical that we blame others. During the bubonic outbreaks for example there was a rise in anti-Semitism; the Jews were blamed. Hundreds of people, Jews especially, were burnt at the stake, buried alive, and tortured in the most unspeakable ways during the time of plague. Although interestingly, Pope Clement vi, who was the pope during the first outbreak of plague in 1347 was surprisingly enlightened actually on this topic. Actually, he was a very interesting man in many regards; his humanity comes through actually from some of his correspondence about the plague. But we also saw the same thing for example with the HIV epidemic in the United States. Gays were blamed or Haitians were blamed or IV drug users were blamed. And during the Covid pandemic, immigrants are blamed always we wish to blame some other person for our predicament. now there’s an interesting set of ideas as to why we might do that. And one idea that I think may hold some water is that human beings find it more appealing to imagine that there’s human agency behind the calamity that has befallen us that actually some other humans are responsible, because that’s much more appealing than the alternatives, which are for example that it’s an implacable god that hates us; that’s not very appealing. Or that it’s the inexorable workings of the natural world which is also not appealing. So, I think if you have to pick between nature, God or someone else is at fault we pick someone else. And this is one of the reasons why blame has been a feature of plagues in my judgment.
There are some ideas we can talk about which we maybe do during the Q&A on how plague is a time of meaning and how meaning arises during times of plague as well and how as well they are a time of loss. Grief walks the streets during times of plague. We lose our lives, we lose our livelihoods, and we lose our way of life. And the kind of psychological malaise that we have seen actually has been described also for thousands of years. Marcus Aurelius talks about how during the plague of 2000 years ago, a plague that afflicted Rome. Yes, the deaths from the germ were bad he said but in some ways the psychological depression was worse, this man observed 2 000 years ago. And what we had to do and we still will have to do is to implement a series of responses that I like to think of in keeping with a something known as the Swiss cheese model.
The Swiss cheese model was a model introduced by psychologist James Reason about 30 years ago to think about the failure of complex socio-technical systems that have biological human and technological components [and] why do they fail. And he thought that there were layers of defense like slices of Swiss cheese, each slice of which was good but imperfect there were some holes in it. So, you can imagine for example that our layers of defense against Covid: masking is a layer, and vaccination is a layer, and quarantine is a layer, and testing is a layer, and hand washing is a layer, and school closure is a layer, and border closure is a layer. So, each of these is a layer of defense but each of these is not perfect; there are some holes in that layer. A certain number of holes and a certain size of holes and they’re randomly distributed. So, you should have the intuition that if you have a single layer of defense the virus could penetrate that layer if it happened to line up with a hole but if you lined up several layers of defense by the time you got to the third or fourth piece of Swiss cheese there would be no sequence of holes that was perfectly aligned.
This is why we need to implement more than one layer of defense, [and] why for example school closure alone is not enough or border closure alone is not enough and also incidentally why vaccination alone is not enough. Vaccines are fantastic but they are not perfect, and this is why for some time we’re going to need to not only be vaccinated but engage in certain other layers of defense like mask wearing and gathering bands and so on. Another important epidemiological idea that I would like to introduce and then I’m going to talk a little bit about the sort of three phases of epidemics and then close with some some final remarks. The idea I’d like to put on the table is this notion of herd immunity.
Now herd immunity is an old concept in epidemiology and it’s the idea that a population of people can be immune from a condition even if not every individual within the population is immune. For example, if you vaccinate 96% of the population against measles and one of the four percent unvaccinated people gets measles you don’t get an outbreak because there’s no one for them to spread it to, they’re surrounded by immune individuals. That 96% is the herd immunity threshold and you should have the intuition that the more contagious is a disease the more infectious it is the higher its r naught the higher the herd immunity threshold. And you can compute the herd immunity threshold by standard formula which is r naught minus 1 divided by r naught. So, for an r naught of three, that’s three minus one divided by three, that means sixty-seven percent of the population needs to be immune either naturally because they survived the infection or artificially because they were vaccinated before you reach this threshold. It turns out for certain network science reasons, I won’t go into that calculation, make certain assumptions which aren’t necessarily true so you have to downwardly revise the number for the original native Wuhan strain the herd immunity threshold was about 50 now it’s gone up with a variance but that’s another whole topic we can discuss.
Anyway, with that little bit of epidemiological background let me sort of talk about what are going to be the three phases of the epidemic and those are the acute the intermediate and the post-pandemic phase. the acute phase of the epidemic is when we’re feeling the biological and epidemiological impact of the virus and that’ll last until we reach herd immunity either naturally or artificially through vaccination. Which means that it’s going to last through the end of 2021 the beginning of 2022 where we’re going to be living in a changed world: wearing masks, having other kinds of non-pharmaceutical interventions that we use to cope with it as the virus moves through the population. But eventually, we will reach this important threshold and thank goodness we’re able to do it mostly through vaccination right now which is another whole topic we could discuss. I’m just giving you a little bit of a flavor now in the 30 minutes that are allotted to me.
Then we’re going to enter the intermediate phase after the immediate phase beginning at the end of 2021 beginning of 2022 and that’s going to last about a year or two, and that is until the end of 2023. That is when we are coping with the clinical psychological economic and social aftershocks of the virus. It’s like a tsunami has washed ashore, [and] now the waters have receded, which is great, but we now need to cope with all the damage. So, probably five times as many people as die of the disease will have some kind of long-term disability. I’m not talking about long or short covid I’m saying you’ve recovered from Covid but your body has been damaged by the infection. You have pulmonary fibrosis you have psychiatric or neurological sequelae or renal or cardiac or pancreatic problems. So, in the United States if as many as a million people die we might have five million Americans that are going to need clinical care who will need resources and hospitals and clinics and other attention we’re going to have millions of children that have missed school and lost a year of schooling will need attention. We’re going to have the psychological sequelae. We’re going to have millions of Americans lost their jobs. Millions of businesses have closed will need to be recapitalized. All of this will take time for us to cope with.
And if you look at the history of epidemics, that typically takes a year or two until we get to the end of 2023 approximately. These are not hard and fast dates; they’re going to feather into each other, but then we will enter the post-pandemic phase, and I think that’s going to be a little bit of a party, a little bit of like the Roaring 1920s of the 21st century like the roaring 20s of the 20th century. I think people will have been cooped up for a long time, and now they’re going to relentlessly seek out social interactions in nightclubs and restaurants and bars and sporting events and political rallies and musical concerts. We might see some sexual licentiousness and some change in sexual mores. My sister when she’s heard me talk about this says “Nicholas you should always hasten to add that that forecast only applies to unmarried couples.” In fact when I made a remarks like this to um a few months ago another location I got the one of the New York tabloids the New York Post gave me. The New York Post headline treatment said “yale professor predicts orgy.” That’s not what I’m saying; I’m just saying that it’s quite natural for human beings who have been denied social interactions to then when the time when the danger threat is finally behind us to have a kind of more liberal kind of social interactions.
Also, during times of plague people save their money; they become more abstemious and risk averse, either because they fear getting sick, for example, they want to conserve their resources, or because the economy is collapsed and there’s nowhere to spend money. But when the plague is over people spend liberally. This has been seen for thousands of years. So you typically have an economic boom afterwards, and I think we’re going to see an entrepreneurial boom and also perhaps an efflorescence of the arts and a kind of very effervescent period of time when we finally put the epidemic behind us.
These respiratory pandemics come in waves; despite vaccination right now we’re going to have a good summer, but it’s a kind of false relief. We’re going to have another bad winter next winter. It won’t be as bad as last winter but we are going to see rising mortality again in the coming winter, probably reimposition of some of the non-pharmaceutical interventions for a host of reasons we can discuss if you want. These vaccinations – these vaccines that we’ve developed – I think we are the first generation of humans alive to have been able in real time to invent a specific and effective countermeasure speedily enough that we can modify the course of the epidemic. Our ancestors when coping with these threats could not do such a thing, but we have been able to do such a thing. These vaccines have been a godsend. I think we’re going to have boosters. Booster shots on the horizon. With these new variants and these new variants that have emerged could put a spanner in the works could affect some of the timing that I’ve just sort of outlined schematically a moment ago. I think the rich nations of the world, including the United States and Canada but also European countries, Japan and so on, china too by the way, have a moral economic and epidemiological rationale for vaccinating the world. I think there’s a moral necessity for us to vaccinate the world. We are the richest nation on earth; we are the scientifically most sophisticated nation; we profess to global leadership; we should lead, and I include Canada in this. We have an economic rationale as well because of course we need global supply chains to be stood up; we need trading partners – other countries. To be rich ourselves, we need people to trade with and and so we need to vaccinate them.
Finally, we have an epidemiological rationale even if you don’t buy the moral argument and you don’t buy the economic argument. In a kind of very selfish save your skin argument you should care that there are places around the world where the virus is running rampant and could mutate into worrisome strains that will inevitably come to our shores and kill us. So, for all these reasons I think we should vaccinate the world and the economic rationale is astonishing. It will cost just 50 billion dollars to vaccinate 70 of the world and the return on that some have estimated are many trillions of dollars. I mean the return on investment is just astonishing.
A couple final remarks. I think it’s important to understand that bad as this epidemic is it could have been so much worse. There’s no God-given reason this pathogen only kills one percent of the people. It infects. It could have killed 10 or 30 percent; we could have been facing a bubonic plague type situation in the 21st century in our rich scientifically advanced democracies. It’s astonishing to contemplate isn’t it. Just dumb luck that the virus is this lethal and not more lethal and the next pandemic could be that lethal. Unlike bubonic plague or cholera for example, which are caused by bacteria for which we have many effective antibiotics, we have no good drugs to treat viruses to speak of. So, our only hope is through vaccination – and it takes time to invent vaccines. So, a deadly virus that kills 10 or 30 percent of the population – we would have been seeing a like in the movie contagion – I mean just an astonishing devastation in our society. This is why these threats need to be seen as a national security threat and why they require great probity not just on the part of the citizenry but also in the part of our leaders and why I was so disgusted at the way we were misled and poorly led in so many of the countries around the world which could have and should have known better. There’s some evidence that these zoonotic diseases – these diseases that originate in animals and leap to humans – are rising with time and that the inter-pandemic interval is shortening. So, earlier at the beginning of my remarks, I said these epic these serious things come every 50 or 100 years, but some people fear – and I am among them – that they now may be coming every 30 to 50 years for example. plus, they’re stochastic meaning that they could come at any time. Just because it took 50 years for this to happen, the next one could come in five years; literally there’s absolutely no reason that it couldn’t happen. So, plagues offer new challenges and new opportunities and I’ve highlighted some of the ways in which in my remarks today. I’ve highlighted some of the ways in which they elicit some bad qualities in us. They also elicit good qualities like collaboration and cooperation and the deployment of our wisdom and science to confront the threats. The fact that thousands of scientists had labored for decades to produce the knowledge that was useful to us and that the world mobilized international organizations [and] cooperated scientists around the world cooperated; tens of thousands of citizens volunteered for these epidemics and countless other sacrifices were made; people sacrificed their money; some health care workers sacrificed their lives to care for us which is another topic we haven’t discussed, and we could talk about. There were many amazing so-called essential workers truckers and people delivering food and so on took tremendous risks to keep our economy somewhat functional, so there were many wonderful qualities that we manifested as well not just bad qualities.
And so I’d like to close with a quote from um Albert Camus a famous novel la peste, the plague, which is a fictionalized account of a plague sweeping the village of Oran in Algeria in the 1940s but is based on an 1849 cholera outbreak and also surely on bubonic plague outbreaks that swept north Africa and Europe in prior centuries. The protagonist of this book is a physician by the name of Dr. Rieux and here’s what Camus writes he says “Dr. Rieux resolved to compile this chronicle so that some memorial of the injustice and outrage done them might endure and to state quite simply what we learn in time of pestilence that there are more things to admire in men and women than to despise.” And that’s very much how I feel about life in general. I’m an optimist. I think we’re a miraculous species. As Ian mentioned, I wrote this other book called Blueprint: the Evolutionary Origins of a Good Society and this is how I like to see how we will see the other side of this 21st century plague that we are facing, thank you.