 And this is the first roundtable that we have on the issue of pandemics. So I let Simon ignite the discussion. Very good. So thank you all for for joining us. I want to introduce our panelists and there'll be some others who But in fact, let me just call on you and let you introduce yourself starting with Lona. Yes, hi, my name is Lona Simon, so I'm a professor here in at university in Denmark. I've been in the US for many years, but I'm here now. I've worked on pandemics for 30 years and this year I spent my entire time working on Kobe and advising the government and and being on the press and everything so I have nothing on my mind right now so it's a good time. I live in a strange country called Sweden, which seems to follow another route than other countries. I'm a professor of economics I'm a mathematician by training and working on game theory, including evolutionary game theory population dynamics and stuff like that. And now I've been working on modeling together with Simon and his lab of epidemiological models, including face masks and so on. I've also worked with the mathematician in France on optimal control of epidemics waves and things like that so I'm an applied mathematician economist you could call me game series. Marino, unfortunately, I'm sorry cannot join with the camera. It doesn't work and I don't know why it usually work. I'm now professor emeritus of ecology at the Polytechnic or Milano Milano Italy. I've been trained as a, wow, as an electronic engineer but let me say like as a mathematical model of basically, but then I started working in ecological modeling 40 years ago. I'm very much interested in disease ecology in the past, let's say 1520 years and okay together with a group of other people. I have developed the, I think that the first spatial model for COVID-19 in Italy. So I'm very much interested in the round table. Josh. I'm Joshua whites professor of biological sciences at Georgia Tech, where I usually work on virus micro dynamics of, you know, again viruses of the small we've also worked over many years on ecological modeling at the modeling. I'm doing some work in response there in this past year have been myself and my team critically involved in many aspects of COVID-19 modeling from estimating are not and then going on to risk, as well as predictive models forecasting models and also with respect to Georgia Tech's implementation of a saliva based testing program and essentially testing is mitigation. Glad to be here. Mercedes. So I'm at the University of Chicago, and I'm a theoretical ecologist working on infectious diseases mostly population dynamics the influence of climate variability and change environmental change, and also the interplay of evolution and ecology. Scott. I just took a mouthful of cereal because I've been on zoom for the last three hours. So I'm at Columbia University. I'm an economist. I work on a variety of issues I have worked on infectious diseases, mainly looking at disease eradication as kind of extreme form of a situation which we rely on countries to cooperate to address the issue. The other end of that spectrum is when you have the emergence of a new disease, those two are kind of two ends of a long spectrum on infectious diseases eradication in the emergence of a new disease and obviously COVID is in that category and one thing we're observing is that the international system is not responding in a very helpful way to COVID. We're entering a new era now with vaccine distribution, which I think is going to be the most critical one for the international perspective but that's that's the aspect that I'm more interested in. Thanks so much. Thank you. So, Wilfrid Nadeefan will not be able to join us today unfortunately he had a death in his family. I expect Ramanan Lakshman Orion to join us I don't see him yet. If you're there and I don't, it's just that I don't see you Ramanan please speak up, but otherwise I suspect he'll be joining us a little bit late. There are many topics that we could address and we've only got 55 minutes to do it in, but I'd like to begin with something that we're, that's right at the core of dealing with COVID and we're all interested in, which is the trade-offs between controlling the disease and making sure that we minimize the number in the hospital and the economic costs to society. And I don't want to approach that from a theoretical point of view at the beginning. I want to take a case study because there are a number of statements that are, there are a number of differences in the way governments have approached it. There's something called the Great Barrington Declaration that's been signed on by a number of libertarian economists and a few public health people. But the most striking difference is the Swedish policy which differs for example from other Nordic countries and how they've approached and most other countries as to how they've opposed the disease, appearing to rely to a large extent on the development of herd immunity by people getting sick. I oversimplify the strategy, but that's also been suggested or was suggested early on in the UK but was quickly reversed after an outcry. And I'd like to turn first to you, Jürgen, since it's a Swedish strategy and you're the suite on the panel, to tell us a little bit about the strategy and what you think about it. And then I'll ask Lona to go next, since she does know Anders Tegnal. You're muted, I think. We can't hear you at all. Okay, I'm sorry. So I'm not a specialist on Corona or viruses but I have looked at this from a modeling viewpoint and also taking part in the debate in Sweden. The early, it was said by Anders Tegnal and also other people that actually herd immunity was what they were thinking of. It was said that it is just as well to let it develop like that, we cannot do much about it and then try to mine them the consequences and protect the fragile and the old. They have later on denied that actually, but this has been documented so journalists know about it and many in the public knows about it so they changed, they changed what they said. They did this and then I would also like to connect to this you said about libertarianism, because it's very well known in economics that there is, you know, an idea of that the market will solve problems. Adam Smith the invisible hand you know if everybody thinks of him or herself, and sitting irrational and systematic way that will benefit everybody. So, you know, a good state of society parade to efficient allocation we call it. Now it's also well known that that only holds on the extremely strong conditions, which are so strong for many economists say that it is it will not happen. And one of the conditions is that there is no externality as we call it. There's no effect of what I'm doing on anybody else I'm only acting through the market. And certainly not the case with an epidemic. So if I take measures to protect others or myself that will have an effect on others it might be that there's a cost for me to you know to take some protective measures. But I will use them too little if I would be thinking of myself only because I don't take into account then the external effect on others that I protect others by doing this thing. Now this is very well known and it's just embarrassment to hear the Swedish authorities talk and understand that in particular, as if they haven't taken class this class of basics, you know, social science. So that they're they kind of neglect so they can say things like this well you can wear a face mask if you like, and, and then, but people then in Sweden, the attitude is that that is a sign of weakness so I know of kids who have been ridiculed and scorned by other kids in school if they wear face masks they don't dare to do it because it considered to be a sign of weakness or that you are not understanding the thing. So it's a I think there is a very, very difficult situation in Sweden and one of the misses they have mistakes that made is you cannot rely on individual decision in such a situation it is a common problem it's a public public bad situation and it's a positive externality of measures that we take as individuals and therefore we have to encourage that. And they don't. I think it's a major mistake. Thank you. And then, if I understand from the latest news. When the Swedish strategy. Initially, there were a lot of deaths, but many of them in nursing homes. The numbers then went down but now they've shot up dramatically and there's a big debate as to what to do in Sweden. Correct. Can I fill in with one little thing there that it was believed by technology that since it was relatively widespread the disease in the spring, it would not be necessary with measures in the fall, because there will be some level of herd immunity. So he actually, they actually relaxed the conditions in the late summer. And then it turned out he was wrong. So, Lana, could you give us the perspective from from Denmark on on on what the Swedes are doing. Yeah, you're, you're muted. Yeah, we can't hear where you're saying. Hello, so about that. Yes, our perspective is geographically we're sitting right on the other side of Sweden, and we are very jealous. They have free lives they wear no masks they they get around the socialize in restaurants and we have had the lockdown so they're more typical of the rest of Europe and the United States. So let me say something because I reveal that I'm actually think that and this is to the economist on this conference here. I think actually that Sweden came up with something that was sustainable a sustainable strategy, which they brought in too late. And then it in the end they deferred they deviated from it and that's why we are they're having a big problem now. But if you look in the mean in the middle space space after they had a disastrous beginning they responded too late they came in only in the end of March with some strong measures such as closing large gatherings. And they may be more careful about their elderly, and then you see their curve of mortality swing around, and they had a sustained epidemic control between May and September. And this might be the most misunderstood fact in the, in the history of this pandemic, but this is the truth. So my point is that if they have introduced that strategy earlier at the time we in Denmark shut down our whole country. We had a sustainable epidemic situation there that and they would have avoided all their deaths in the other sector. And so, in effect they're really showing us the way to if the vaccines didn't work. Maybe the sweets are onto something here and I am missing that debate and that angle here. I want to say that there's a in the end of the day they ended up just like you said you're and they actually said okay, it's going very well. They were the poster child of Europe then with the lowest infection rate in Europe. And despite all the openness and they said fine let's open up the big conference, the big meetings and they went from 50 up to 300 and what happens fall happened and schools always happen. And all of a sudden there's there's been a major bad situation right now, but I don't think that has anything to do with the strategy that that brought them safely through the from from March from May to September. So I'm, I'm, I'm ready to stand up for another signal that I think they were lucky but they definitely onto something. Lona, you were one of those who wrote in opposition to the great barrington declaration. What's the difference between the Swedish strategy and the great barrington recommendation. The great barrington declaration is all about a we should just put the old people in a closet on a basement somewhere and then the rest of us ripped through this epidemic it's nothing severe. I have so many reasons for for objecting to that that's not even funny. And if you notice the people who signed that declaration that they're not the infectious disease epidemiologists that you usually seen this field. They all signed something called the john snow memorandum. And I'm not a fan of signing things like that but I actually signed this one because I think it's a pretty important discussion to have and show that we were many people thought differently about it. I don't think this has anything to do with Sweden by the way. Josh, you've thought a lot about these sorts of issues and various strategies. Maybe you can weigh in on this. Yes, I'll say a couple of comments are we are talking about dichotomies and I think one of the things that's been problematic from the beginning is the option of dichotomies. And I think there's been a false dichotomous thinking from the outset, when all you have is a lockdown maybe the only alternative is open it all up, but why are those the only two options that play. And so one of the things if we go back to the sort of initial, the Swedish case I mean look if you look at the daily mortality compare it to Denmark or to Norway or to Finland. So we're talking 10, depending on which country 10 in some cases more full higher so obviously there's something that went very wrong there, especially with vulnerable people but still had. These were people's parents and grandparents and loved ones and so on. Where we've tried to make an impact is to try to both inform and also address alternative strategies and the one that we've tried to work on both in theory but in practice is testing as a form of mitigation. Particularly now one of the big worries I have is that we're entering this vaccine phase where I think there's a sense well good thing is on the way and it is it's incredibly good. But we are also a period in the United States where there's tremendous amount of spread there's been a resurgence we're getting 3000 fatalities a day. And that doesn't seem like it will stop soon, in part because of Thanksgiving and meetings there but also because we haven't invested in universal mass wearing and as virus testing as a form of mitigation that tech we ended up like you why you see like many other places making this investment. And that needs to then transition to the next level which is state and national level using a part of an intervention policy and I'll just have one last comment there, which is, you know there's this sort of crazy Trump in comment about, we have so many cases because we test so much. So let's flip that around and basically say that in the near term, more testing will lead to more documented cases, but fewer actual cases in the long term, and we've seen in practice here at tech. The identification early of outbreaks means that we can actually stop change of transmission before they start and so when I hear this sort of options, I'd like us to on this panel at least open the idea there are more options. There's a lot of ways to lock down or open all up there's lots of ways to be more targeted in productive sense I hope we get to some of that. Okay. Others, I don't want to put anybody on the spot because I called on the people that I know I've been working on these things but Marino Mercedes Scott. I wonder if any of you have any thoughts that you'd like to share on this. Yes. You joined us now too. I joined I use your link Simon I wasn't able to make it work with mine. Just just to let Romana know what we're discussing. We're talking about herd immunity strategies the Swedish strategy, the Great Barrington declaration and the trade us in general between minimizing the number of cases and possible damage to the economy. So, go ahead, Scott, were you were you about to. Yeah, well, can I have a word, Simon. No, Marino. Okay, I'm sorry. Yes, go ahead. No, well, you know, there are different containment measures that you can implement and you're I'm not an economist but according to my idea they have different costs. So, for instance, wearing a mask or, you know, protection is very inexpensive. Let me say, because Italy was the first hit country in Europe, that it is incredible that you know that this very simple containment measure were not implemented from the very very beginning. They're very expensive. And you look at one month time to prepare to get ready. Because, you know, the first documented case in Italy was the end of February, now 21 February. And we already know we already, we had already an idea of what was going on in China. And therefore we had one month. And, you know, masks are really inexpensive. Okay. Now, of course, if you stop, if you stop traveling, that's much more costly. So, my idea that really Europe was missing an opportunity. And so, you have to go into lockdown now again. And if it is now a lockdown my especially my my region lovely where I'm even getting out of conditions. And that is due to the fact that people, you know, were communicated the wrong message that everything was over. And then that back to the sheer truth. And according to me, they are different, the different option of really very, very, very different costs. And they, you know, and, well, we, we, we conducted a study of that so, you know, reducing mobility cannot can never bring are not below one. So, you know, reducing transmission rates, it can isolation and testing is more costly, of course, then wearing an inexpensive mask and face cover. And it is more effective if you can isolate people identify an item. That's, that's my, my idea. Can I make a few. Yeah, go ahead. So, so yes, some very rapid comments. One of the, I think, behind perhaps some of the people who signed that declaration and do some modeling of disease. And there is an interesting issue that I think has to be resolved is that, you know, we have a poor sense of the levels of herd immunity that must be reached. And part of the problem there is with the estimates of how the heterogeneity and susceptibility modifies are zero and I think there was very interesting work by Gabriella Gomez and her kinds of models in epidemiology looking at, I think it's a beginning in that direction but it is a problem. How do we deal with that heterogeneity. And what does it mean for the, for the level of herd immunity. And I think that that may have perhaps misled some people to think that, that that level should was lower. I don't know because I think there is tremendous uncertainty on that number. Second comment alone mentioned the May to September reduction I think a big elephant in the room for covid is the role of seasonality and the role of climate factors influence many, many routes not just direct effects on the virus but also on behavior and there is a paper by Javier Rodo and while I mean it but mainly by them showing clear effects of seasonal climate, which by the way previous modeling said should have an effect given the very large number of susceptibles. That is not the picture and I think the mean field models are sending us in the wrong direction. Marino mentioned travel and my last comment is that I think they have handled travel at the very interesting scale, the large scale right of travel between cities. There is a question of movement at the micro scales. And I think that is a much more difficult issue. Could I just, sorry, Sam, could a very brief comment to Mercedes first point, if I just may say that one thing. You talked about the heterogeneity. And that is, I think also super important and I just want to alert you that there is a science article recent one by Tom Britain, Swedish mathematical biologist published in science. I have seen the paper yes Tom Britain published this the paper by Gabriella Gomez had been out in the archives for a while and she has been modeling these kinds of things so yes they are in the same direction and I think people should look at it. I would recommend young people here who are interested in doing work in a modeling this is one aspect I think would be need a lot of more work. I agree. God. Thanks so much great great comments from everyone. So I want to go back to your Bible's introduction, I think it's really important for epidemiologists to understand and integrate human behavior into their models. And basically where he was starting off was this, what we would call a kind of a competitive equilibrium when people are acting individually. Basically they're going to be inclined more or less, when you bring when you bring richness of human behavior into accounting gets get a little complicated but they're going to be ignoring a big part of the effect of their own choices and actions on others. So the result of all that is that you would expect in any society that there would be too little social protection. And that's completely to be expected and that's why we have public health policies. And that's why there's a conflict inherent in this situation between the public and the private. And I think that's really important to understand, because when, if people are asked to take measures, we need to understand that there's a reason why they wouldn't do that on their own. And what I would say about the policies we've adopted is they haven't always understood the motivations that are coming from individuals. Now, this gets super complicated because we have a lot of very bizarre things going on with human behavior. I think we're going to get to probably later in the session about social norms but also about beliefs and so on. I hope we get to that later, but even leaving that out. So what you actually need, if you really want to change that outcome is you need to change the incentives people are facing. And one thing I've noticed is there's been a disconnect between a lot of the economic policies that have been adopted and this goes back to your original question, Simon, about how to trade off control of the pandemic with maintenance of economic function. For example, asking people to stay home, while at the same time not compensating them for a loss of income to work. There are interventions that you can take from the point of view of public policy that would reinforce the public health policy. So these two things have to be synchronized. And where we've seen a lot of problems is because there has not been this synchronization, they've been out of step. And then there's this tension and people are upset and they're pointing fingers, and they're fabricating all sorts of myths as well. What I'm trying to get to is that that tension is to be expected and that's why those policies need to be integrated. I can also add in dynamic sense, I think this also, we should not be surprised that there would be waves, and that public policy could even enhance or amplify the waves. Before I go on to the other panelists, I just want to say that Scott implied correctly that I had a list of about 10 questions I was going to address. We'll be lucky to get through two today, but that's okay because I think that this particular issue lays bare a lot of questions and things I talked about on Monday in my lecture, which was the importance of looking at things like social norms and public goods problems. And if we get no further than talking about those things today, and why the theoretical ecologists ought to be thinking about those things, I think we will have done. Ramanan, why don't I go on to you, and then back to Josh and Lona. Yeah, sorry to have joined late so I don't know if some of this has already been discussed, but you know, just for, you know, back in March or April, you know, one of India's biologists lead biologists and I wrote a piece in Indian pediatrics, which is the main journal for the pediatric association, saying that, you know, in the absence of the ability to really control the epidemic in India, which we thought was difficult to given the density of population that a gradual acquisition of herd immunity was not a desirable outcome. It was not meant to be an intended strategy but it would be an unintended consequence of the way things were going and by the time December rolled around, that transmission would have slowed down significantly because there would be pockets where there was significant amount of exposure already. Now, India's been through some severe lockdowns but this seems to have come to pass, which is that the positivity rates are now quite low, it hasn't India's not seen, you know, the large number of cases or the deaths in recent months compared to earlier in the epidemic. And age structure of population also makes a difference. So I think that what works in one country might not work in all countries because of, you know, again, age structure, which is if you have a lot of young people and just for comparison, in India, there are about 6.5% of the population is above the age of 65. I believe that proportion for China is about 10 or 11%. That number for the UK is about 18% and that number for Italy is about 22%. So I think, you know, these discussions have to be tailored to what that age structure of the population really is. If you have a lot of young people who get the disease, but sort of act as a, you know, a buffer against the older folks getting it, which seems to have happened in many places in India. Perhaps you don't see the kind of rapid number of deaths of the elderly population that you've seen in other places. That said, there are still other issues which are that, you know, in sort of one large COVID epidemiology study that we published a couple, actually last month. Interestingly, mortality rates are actually quite high in the age group from 40 to 70 in India, compared to most other countries where that mortality rate is actually highest in the 85 plus population for the most part. Now, you have some sort of a selection effect where people who have reached the age of 85, you know, essentially because they made it there, they probably, you know, have fewer comorbidities, they didn't die earlier, so they kind of talk for them the ones, you know, compared to sort of in other countries. So compared to other countries, you know, compared to China, Italy, Brazil, the US, India is above 85 mortality rate is actually the lowest, in fact. But it's highest in the 40 to 70 age group, probably because of undetected hypertension and diabetes, which are major risk factors. And in fact, you know, all the COVID is an infectious disease. This comorbidity driving mortality is such an important effect. And I think, again, the answer to whether you go with, you know, acquisition of herd immunity or, you know, you try to shut down to make things happen. Again, depends on the proportion of the population that is diabetic or hypertensive. In our study, we looked at about 5700 deaths. I think about 64% had at least one comorbidity and something like 35% if I remember right had two comorbidities. So the comorbidity stuff is really quite important. And I think that an age structure together will really, you know, be guiding principles for whether, you know, what sort of strategy one might want to adopt. I don't think there's sort of a universal idea here, which, you know, in all conditions, they would do one or the other. Josh, you had your hand up and this is a very natural segue into things like in terms of shield populations that you've contributed a lot about so I know you have thoughts on that then that probably wasn't why you raised your hand before but go ahead with whatever you want. Okay, I'll try to make a bridge which is that I think one of the challenges you're talking whether it's great Barrington or even just how to interpret peaks has been one of the most challenging things in this whole epidemic. The timing of those may differ, but the temptation to assign or ascribe the mechanism of reaching a herd immunity threshold in these early peaks, I think has been deeply problematic and Mercedes I'm aware of that heterogeneity work I think it's very good we've also worked on some sort of heterogeneity issues. But the thing going back to Scott's comment about behavior is that it's clear the header, the herd immunity threshold depends not just on the fraction of individuals who may be a logically naive but also on the behavior of individuals I think people have misconflated those ideas. So in a paper that just came out that you can be aware of transmission change behavior as a result of transmission and get a peak that goes away and then come back as our awareness fades, and especially if there's fatigue so you can get more than one peak, having nothing to do with crossing this herd immunity threshold and I think that's been a big mistake for people to misinterpret and heterogeneity yes it can be there. So let's look at places like fishing boats. And that's a case where it's very hard to isolate as you'll know and see 85% plus attack rates in a short period of time. So if we start to act as if we're on fishing boats, meaning going out and interacting in large groups, then it's going to be the case that we're going to see increases and I don't have to go to the fishing boat I can look at Greek houses here in the United States and I'm going to be doing some on this campus, in which, maybe not through fall to their own but just the introduction of a case and then living situations. And so I frame that only in the sense that I think that this notion of heterogeneity can exist but also not necessarily be explanatory vis-a-vis peaks. And the last thing I'll just, yeah, and then I'll wait the shield immunity can be a different time so. I'm happy to have you talk about the shield immunity. Josh, I just want to point out for this broad audience that when Josh talks about Greek houses, he means fraternity houses. Yes, sorry, that's right. We call them Greek houses fraternity and sorority so we call them Greek houses but dense live, learn environments on a campus. Sorry about that, yes. Josh, do comment on the on the shield immunity. I'll just make a brief comment because I see Mercedes and I wanted to say so very, very, very briefly only that from the outset, we have hoped that testing both for a virus and for antibodies could be incorporated as part of response strategies. And the virus testing I think is obvious. But the antibody testing we viewed as very important in so far as there was a lot of evidence that this was not going to be a seasonal beta coronavirus issue that there was going to be protection that we can't know how far out, but many months at least if not longer, and that individuals who might be seropositive might be able to take on additional roles particularly in protecting those who might be vulnerable and I think again we've missed multiple opportunities to go from imperfect but actionable information and avoid it for some reason to take action on with another cost, which is not leveraging that test information to act differently to try to get more targeted. And in lieu of targeted responses we're stuck with lockdowns which we know have cost so that's a brief summary. And we'll start with Lona. Yeah, comment. Again, we have had so many exciting things just thrown on the table and there's no time to Scott. I think you'll be happy to know in Denmark we actually have surveillance system of people's behavior. And this goes into the models that actually are used to figure out what's going to happen in the future and the forecast and all of this. We have seen people in the public domain if you want to see us into. Mercedes about the herd immunity we have observed this. We've seen herd immunity in the northern Amazonas in the in the town there we've seen it in the Bergamo Italy, for those of you who are in Italy, and we've seen it in the in the slum areas where it seems to peak at 60% zero zero positives. It seems to be something around there. And probably this heterogeneity we have with this disease will mean that it's it's definitely not going to be higher than that. And I also want to say that that one thing that's really important for us to mention in this conversation is that this we looked at pandemics of influenza for a long time now. I looked myself for 100 years of worth of them. And this year is a totally different beast because it has this over dispersion is heterogeneity in the spread. Together with colleagues at the news boys to we actually have used an agent based model to incorporate this fact that only 10% of people spread most of the disease going forward. And we are we just we just so excited to that we think that actually the solution lies in controlling the, this the context in the public space, and there's way to do that without really being able to pinpoint who is the super spread that you can come the closest down. So for me that's the one really exciting thing that has happened during this whole pandemic is that understanding that flu is one thing is like a freight train you can't stop it. But this one you have a little button you can dial up and down if you can afford it. That has everything to do with this over dispersion heterogeneity phenomenon. I just thought I would say that for savings. Yes, so I agree, Josh, you brought a very important issue I didn't mean to say by herd immunity to turn around of the pigs. In fact, it's a complete misconception that the turnaround of these peaks of these first peaks had to do with herd immunity. I just meant herd immunity estimated from these susceptibility malls is lower than than in other estimates. Now in in response to to what determines the pigs. And of course, there is a very an interaction between herd immunity and possibly seasonality due to policies and climate and I think we see this of course in diseases that you can say are as I am very different from Kobe because we know they are seasonally driven like dengue where you get emergent serotypes lasting two or three peaks. And I think what determines the pigs is a very interesting interaction between the the the transmission dynamics and the timing of this of the changes in transmission due to due to seasonality and I think whether that seasonality comes to behavior and to a myriad factors that influence the virus, we will find that it plays a role here and how it interacts with policy makes for a very confusing, unfortunately a very difficult inferential aspect of this disease. Marino. Well, I know a comment on it originally I don't know what you mean exactly by it originally. We say that but we included the region it is in our first effort in Italy because the, the model that we conceived that was actually space explicit. So we're including 107 provinces in Italy, and looking at the spread of the disease and Italy. It started in the north and then it went to the south. And then when the crisis was considered over and people were allowed to to go to the seaside the thing in Slovenia and Sicily is spread to the Slovenia system. Now, you can actually calculate and are not, which is are not which includes the geographical, at least the, the mobility, let's, let's say, that of course there are other interogeneities, the original behavior, different age classes behavior in a different way. The susceptibility in the different age classes and the different say working environment is different and so on and so on. But after all, for all the studies around the world are not without any intervention is about three, let me say that that might be 3.5 might be 2.7, but anyway, everywhere, of course, it might be different in So talking about herd immunity to me is ridiculous, let me say, because with another not, which is about three, 3.5, 2.7, whatever you want herd immunity is rich when about two thirds of the population is being infected. Now, two thirds of the population being infected means a lot of death and incredible and incredible amount. Okay, so we had a result from several zero prevalence studies so in Italy around July 15, there was a sort of sample all over Italy, and you know, the zero prevalence in Lombardy, which was my region, 7.5%, that's the highest in Italy. Other region was 2.5%. So it means that, you know, before reaching herd immunity. Of course, there are some specific location. So if you go for instance to Bergamo in a valley, they have 40% people be infected. Okay. The second thing is that we already know that you can be reinfected that this talking about. Okay, I will cite you one case for instance that you know there was a seminar by Antonella Viola a few days ago. And they have seen in Padua, one guy who got infected, recovered, then he was reinfected again and died. So it is somehow clear that immunity might last just a few months. So these ideas of reaching the herd immunity. Let me see. I don't know it. I'd like to. Let's let Lona, because I think that's a controversial point about whether the individuals actually recovered and got so long ago. Yeah, I'm aware of this having occurred. Even one got more sick the second time than the other. But I think we can know for sure now that this is not very common. We see that for example in Bergamo, Italy right now, which was had this terrific herd immunity in the first wave. It is faring very well in the second wave. Opposite other towns in northern Italy, which I have had a very bad second wave. So that's just one of many lines of evidence that I think that's, that's not going to be an important one and the bodies are okay. Even in Iceland, you can now travel in with an antibody passport. On this issue of super spreaders by the way, you may have seen that this one biogen meeting in Boston apparently was accounted for about 300,000 cases. So that's it. So I'd like to call Daniel Fisher I don't know Daniel whether you can unmute yourself. Okay, go ahead. Yes, I can. I'm a theoretical physicist at Stanford and my only direct relevance for this seven work a little bit on on spatial spread by a long distance motion in abstract models. I wanted to actually ask a question about homogeneity not about them, a heterogeneity so in the spring if I looked at New York City, and you looked at all of the the high density parts going all the way out to the rich low density suburbs, the variations in number of cases were not all that high, then there were factors of two maybe three in some case but not enormous. If you look at LA in the spring, they're again going from the higher density poorer areas to the low density richer ones, there was also not all that much variability but the whole area with much slower than New York. And I wonder if there are any thoughts as to what the explanations are of some of that. I think Josh made the comment that clearly in most places at least the number of what the Los Deceptibles was not playing a role and certainly not in those, I think in LA area there but then what is it that can give rise to that level of homogeneity within regions. Anybody want to respond to that. Yeah. Yeah, I'm also a theoretical physicist and actually me and my students started to, you know, work on some models since February, because I think, you know, starting in China and we were really, you know, wondering what's happening and whether things we can do, make some models or inform the policy makers and so on. But, I mean, answering Daniel's question. I mean these early models we just took the standard approach from epidemiological community, and we'll mix and so on and now people, of course, thinking about heterogeneity but I think that probably is not really the most crucial issue. Because after initially these growth, exponential growth, there's some variability, maybe are zero different places somewhat different. But after some time, then you always see that it kind of level off at some some value. And I think Daniel is asking which value, right. So it's, it really has to do, I think the human factor is very important that people get scared, and they take more precautions, whatever community they belong to. And then you kind of bring down the growth and eventually you will reach, like, as we could do one or something. If you start to see the decline, sometimes you have to overshoot a little bit but then some kind of declining. But once people see this declining, then they kind of tend to relax. But doing this, this first wave people still, they are very cautious, you know, they don't immediately relax. And that's what we see in Hong Kong and we're actually now in the fourth wave. So I think this, the overall level is really has to do with the local community, how they are like worried. They, how much precaution they take themselves, in addition to what the government is doing. So, I think this kind of a self-imposed kind of behavior changes. That could, you know, at some point will bring down, because everyone now watching the news, right. So maybe they are seeing the increase or decrease more than the absolute value. And they kind of respond to the growth and not maybe instead of the absolute value. And so if the local community they are, you know, take this kind of precaution earlier, then it will stop, it will level off at the lower level. So that's my kind of interpretation. I agree. I mean, I think the only reason for interpretation is that there are, you know, rather long range of behavioral changes you respond most of things right nearby you respond. Some of the things applied of the city because of some amount of mixing in the city, but not enough to give you like a well mixed situation, and then you respond less to things in the whole country and you know less even to the whole world. So I think it is something but it's surprising that that gets you to some of these levels of homogeneity that there are. And I think those things naturally give rise to sort of can give rise to dynamical to waves. So a very quick comment first of all in Georgia, we saw imprints of heterogeneity that lasted a while for example in Albany Georgia Southwest there was a funeral that sparked an outbreak and that led to an imprint locally in that county and adjoining counties for quite some time that we would not have expected if we just assumed homogeneity in New York City. There's strong relationships between socioeconomic levels and incidents, and in particular with the number of residents for household Jeff shaman make I love Martinez and a few others have done these sorts of studies. So you see those factors there's also relationship to ability not to take the subway. So there may have been you know some gaps between awareness at the outset but they're definitely relate, you know, let's say, links between socio economic factors mobility, housing and incidents. So I'm just trying to add those layers into your comment about homogeneity. I mean those would give rise to a lot of heterogeneities and you know we change is an exponential growth rate you expect all those things to be amplified. And so that has to be rather a big effect that sort of suppresses them to get the sort of lack of heterogeneities of in on some of the scales but yeah anyway that's it's enough on this point. Now and then to your again. Yeah, thanks, Simon. So, you know, I teach a class in Princeton where the main theme really is around this whole idea of people responding with behavior to to prevalence and you know there are lots of examples of course from HIV, which is in some cases of slightly more stable disease because people get to observe it and then, you know, get to respond to it in terms of their risk taking behavior. I am not sure if, if that is really panned out in the case of covert for a couple of reasons. One is adapting to the presence out there requires having fairly good information about how bad things are out there. I don't think the level of testing has been nearly enough in most countries to be able to support that kind of data. We know from zero preference studies that you know, at least in some countries we're picking up one out of every 20 cases or one out of every 30 cases. So we don't really have a good handle. And when I say we even people who are studying this don't have a good handle, let alone individuals individuals are responding to waves of panic on the media. You know how many shows they watch which are not necessarily correlated with you know what what the true nature spread is because there's been spreading lots of places where the testing has been wholly inadequate and therefore it isn't as if they're responding to something which is very rational. That's the first point. The second is that just because it's a new disease. I think people have been have found it quite difficult at least for the first six months to act to accurately calibrate their risk. Or risk taking behavior to the disease in a way that actually makes sense. What do I mean by that? It really means that for HIV you knew it was actually transmitted. So if you didn't have needle exchanges or you didn't have, you know, blood transfusion or you weren't having unsafe sex, you were pretty safe. Here people weren't clear whether to pick up the newspaper. They weren't clear whether to go play tennis or, you know, to go out of the park. So given that there was so much confusion about what risky behavior constituted and what was safe behavior. I'm not entirely convinced that for that long period probably from March through to August or September that people had any clue what they were doing or, you know, or if even governments had a clue about things that were actually problematic versus non-problematic. And I think, you know, some places get bars open but shut down schools, you know, some places shut down schools and, you know, sorry, get schools open but shut down the bars. I think there's a lot of confusion out there. And this sort of, you know, stable understanding of what's driving these peaks up and then driving them down, I think is a result of a lot of confused behavior rather than really of what I would call rational behavior. Because it's all with fairly incomplete information. Very good. Jürgen, you had your hand up, I think. I can't hear anything from you, Jürgen. Yeah. All right. Thank you. Yes. Now I wanted to follow up on this with behavior that Scott was taking up some little remarks that, you know, from an economic theory of view point you think of individuals as being fully rational and selfish. And they take out in any information they can and they can treat information in a good statistical way so they can make inference about things that they see about around them. And we know of course that that is a very formal of real life human beings in many dimensions. One is the belief formation and there can be these panicky situations and things like that, but also the motivational part I would say. So the strict egotistic, you know, motivation which is a classical economics motor of behavior is not true, we know. And one situation when it's not true is when you have a public good situation in a small community of people who meet regularly over long times and so on. So we like in the village and the family, people do care for each other in another way then and that can be explained by game theory and so on. And that's one thing. Another thing which is very important, which has been added now in economics to economic incentives are social incentives social norms that we are social animals and we care about what other things about us and our behavior. And that's very clear and I think that this is not what has not been used by some policy authorities one could use this. I mean, I think of smoking the anti smoking campaign was very successful. But because you can see and smell the smoke in the restaurant and people don't smoke you don't need to have a policeman in a restaurant. People will frown upon those who go in there and smoke. You don't see the corona that I'm spreading perhaps in when I go into a shop, but I'm now in Norway and in Norway if you don't wear a mask when you face mask when you go in people will frown upon you even to ask you to go out and so on. While in Sweden they don't so I think there is a social norm but but it could be used in a positive way that we have something common to think about and care for also to those who are not very close to us. And that is something I think is up to political leaders and agencies to inspire that. And we also know from experiments that individuals they are not purely selfish not surprisingly. There is a tendency in most humans to have some moral component that we would like to do things that we think are the good and right things we have some tendency not to very strong is heterogeneity again. But if I'm inspired these these things, one can get much beyond what we have now. And this is something which I think we need to incorporate into the classical SiR models and so on the popular population models in epidemiology, which are rather mechanical on the behavioral side so I think we could combine here. There are many fields and combine behavioral understanding and economics and game theory and and these dynamics that will give a richer model and possibly better ways to try to influence the control and epidemic for example. Thank you. Marino. Well, you know, a comment. I think that, you know, what has been working. Clearly, heterogeneity is important and heterogeneity in social behaviors important and you see the difference. So for us to take Japan, and they had a very low number of people who died and they didn't go into a real lockdown like Italy, but lockdown in Italy work. And, and, you know, then they, they released a lockdown and then after a while, we started again with the second to be the way. And now they went into lockdown again later than, than what I mean. I would have, I would have implemented lockdown earlier, given what was going on in Italy. And, and now the numbers are going down again. So clearly the, the, the, the containment measures are, are working and Well, you know, the homogeneity, you see now is clearly due to the spatial, the spatial diffusion of the disease. So it is the, the, the, the spatial signature is clear with the, the, the COVID starting in China that spreading the rest of the world with the mainly through air travels and then going to countries and then sufferings is reaching Italy and Of course, the, the force in Italy were in the northern part of Italy because it did the mostly industrialized the part of Italy with a lot of the connection with the rest of the world. And then it went south and when the tourism season started, and so on and so on seasonality. Well, it is clear that COVID is spread mainly when you are inside a, inside a closed environment. So clearly during summer, the contacts are not so close. And in fact, there is an interesting remark that it went up in summer in Texas and Arizona, good people want air conditioning. So they stay inside and most of the of the contacts are inside a closed environment. And it is very clear now that the main, that the main way that the disease is spread is the respiratory and close contacts and the aerosol and the droplets. So clearly seasonality is related to that fact, and also it's related to comorbidities because clearly during winter respiratory disease and ailments are more common. So old people, you know, might suffer from comorbidities, especially during winter. But I would say that that lockdowns were the most effective way of limiting the disease. That's my opinion. Thank you. One last quick comment from Scott and then we have to tie things up. Yes, just very quickly just to kind of echo build on what you're going to said, I agree with everything. Social norms and go in the two directions of course. So there's a social norm to wear a mask. There's a social war norm not to wear a mask and we're seeing both of those things. There's another aspect of this though that I think is really important, and that is where people get their beliefs, and it's very strong evidence that beliefs. There's not only the normal variation but that there's a correlation with people's ideological identities. You see it very strongly in the United States but I think it's also in the UK and other places. And this is really I think a real problem for us because because of the political connections and also through social media basically introduces the ability of others to manipulate beliefs. And I feel like this is something that's happening on a pretty massive scale, and it's making the normal kind of public health policies, really difficult to implement. So we have the other problems mentioned before. Ramana mentioned that we don't get to observe prevalence. We also people are transmitting without symptoms are all sorts of other complexities are already there. We have all the normal richness of human behavior but on top of that we've got this very disturbing. So we have to be able to see the originating and populations in terms of their beliefs and where those beliefs are also being manipulated by others for political and other purposes. Thank you. So, this has been an incredibly rich discussion we got almost through the first question I had laid out. I hope that the first one I want to thank all the panelists and the others who chimed in. I hope this is convinced people of what I was arguing in my lecture on Monday which is, if we're going to go forward to solve not just problems of this sort having to do with pandemics but also climate change and other issues. We've got to have more sophisticated incorporation of economics and social factors in human behaviors, looking at things like social norms and pro-sociality political polarization as Scott was just mentioning, etc. So, we could have gone on for three hours on this, but it's been a great discussion and thanks very much. We've got another panel discussion tomorrow on economics more generally so and anybody anybody the panelists who want to chime in and listen to that I'm sure just drop us a note and we'll make sure that I think the same link will work though that you use today. Mateo or Jacopo, Jacopo, what time is that panel tomorrow? So, it's half past two. It's half past two. European time so that's I guess what 830 in the east coast of the United States. Yes, yes. Okay, very good. Thank you all very much. Great discussion. Thank you very much. The school resumes tomorrow at 12. So, have a nice evening or day or whatever. Thank you. Thank you. Happy. Thanks, Simon. Happy New Year.