Prof Chris Whitty: How to Control a Pandemic

Tonight I thought I would talk about epidemics and the reason I chose this is a topic and I chose infectious diseases as my first year of lectures is because they were in this year that we are entering, which is the 500th year of The Birth of Atomics Gresham was by far the dominant part of medicine, so when this College was founded, medicine was largely focused on infectious diseases and, broadly speaking, they are divided into endemic diseases, diseases that are there all the time. time in the background and there were many during. During the lifetime of Sir Thomas Gresham, during which epidemics occur in which there is suddenly an increase in a particular infection and during his lifetime there were many epidemics that we know almost certainly many epidemics that we do not know about, so they were , for example, moderately. large plague epidemics here in London, a syphilis epidemic that actually occurred throughout his life and that in many ways came to an end only at the beginning of this century in our century, more like a smallpox epidemic in a context of epidemics continuous bouts of typhus and a disease that was considered quite unique to the United Kingdom, the United Kingdom, the English sweat shift disease, of which there were two major outbreaks in its lifetime, so there were many epidemics at that stage, now plays a gift that, as I say, had two epidemics in its lifetime, is an example of the The extraordinary power that infectious diseases have historically had to shape the history of humanity, but also the human capacity to respond to those who say "yes ", exact estimates are obviously difficult and opinions vary, but I think most people who have looked at this consider that the game reduced the world's population.

During one of its largest

pandemic

s, from about 450 million to about 350 million, perhaps a little more than that, in the 14th century there was a staggering drop in global mortality and in Europe, which was hit hard, among 30 and 60 percent of the European population died. The impact of that on society clearly cannot be overstated. The risk of a plague epidemic or

pandemic

, now significant, is now zero, although epidemic lords will occur again to this day. However, it is also the centenary year and the centenary month of the last time. serious global pandemic and that was the 1918 influenza 20 H1n1 pandemic, also known as the Spanish flu, which probably killed between fifty and one hundred million people and to put it in some perspective, I just showed the number of deaths in the United States United States, where The data is reasonably reliable when comparing the number of people who died in that flu pandemic in the US with all the people who died in all the wars of the last century in the US.

More people died in that one pandemic that everyone in the US who died in every war first world war second world war Vietnam and Korea that puts into perspective how bad this was and like I say there are people living today who lived through that pandemic, this kind of epidemics and pandemics can appear extraordinarily suddenly and spread very quickly, so let's take the 1918 pandemic and I'm taking the US because we combine good data and great geography. Looking at this map that we have here on the screen, what you can see in dark colors is the area where it entered the United States. and it spread before September 14 of that year, this was exactly one hundred years ago.

The areas in the light colors, most of which are relatively remote, are where it arrived after October 5, so the spread across the US occurred in a period when there was very limited transportation just after the war for a period of less than a month and if you look at the increase in mortality that we saw in that year, comparing October of that year with October of previous years, they were years of deprivation. This is during war, you can see the massive impact that mortality had just in this month of October exactly one hundred years ago, so when really serious pandemics occur, they hit society with extraordinary force and speed and They were doing it even in earlier times. industrial times, so think about the game or the syphilis epidemic that was actually going on during Sir Thomas's lifetime.

This is, for example, a map of the plagues spread and what you can see is that it spread very quickly throughout Europe in a medieval period when transport was considerably slower than it is now, although not as slow as I think it is. people can imagine and, for example, a syphilis which, as far as we know, was a new disease in Europe around 1494, spread after the battle of Naples throughout the continent, probably in a matter of months and was certainly recorded as to the north like Leif for example in 1497 so these diseases could spread even in periods when our transport was much slower so it is possible but wrong but many newspapers make this point incorrectly , so I will do it. for them and then say that it is wrong that we are increasingly vulnerable to epidemics due to the enormous transport networks we have by land, sea and air.

This is just a map of transport connections in the world. How many places can you reach in 24 hours? and as you can see the UK is right in the middle, however the reason this is not as worrying as it seems is that being rich as a society greatly hardens society against epidemics of any kind and it doesn't. mainly for reasons of medicine, which will then come to medicine, but in fact, because of all the other things that lead to a successful wealthy society, agriculture, for example, leads to substantially better nutritional engineering, leads to better sanitation of housing, clean and abundant water and cleaner heating as examples, so there are many things we do with societies that are not designed to prevent epidemics, but do so simply as a process as countries become richer and developed, but that does not mean that the epidemics have gone far from that, I listed only six up here and there are many others.

I could have chosen just six of the epidemics that have occurred in this year 2018. In the top row I have shown three that would have been well known to the citizens of London at the time. At this university there is a significant outbreak of multidrug-resistant typhoid in Pakistan , cholera in Zimbabwe and Yemen. I will go back to Yemen and a plague in Madagascar and we are about to enter the plague season so I am anticipating a second plague epidemic there occurs quite frequently and in the bottom row some diseases that were not known in the smoke era of cigars particularly Sir Thomas in London but they are quite widespread at the moment an outbreak of monkeypox in Nigeria had this happen in London at that stage people would have assumed that this is smallpox, they look almost identical, which actually has been, there are now three cases this year in the United Kingdom, which has spread due to the Middle East coronavirus outbreak that is occurring particularly in Saudi Arabia.

A real concern for people is that people throng during the Hajj and other pilgrimages and then disperse to the four corners of the world, often to places with relatively limited health services, and to the bowling outbreaks that have occurred in the Democratic Republic of the Congo this year, one of which is still ongoing and there are many others, so what I want to say about that is that epidemics occur every year on all continents and they kill people. Its social impact will depend on many factors. It will depend on how many people and who are affected. and it is possible that certain social groups are more important to the functioning of society and are not more important to their families;

For example, the great flu pandemic of a hundred years ago caused especially mortality in young people of working age, so the impact on society was very considerable. All flu tends to kill very and very old people, this also selected to young people of working age and many pandemics, and then I will give an example of this, they tend to select people who are health workers, which makes the response considerably more difficult and I have given an example from Nigeria, this is just an outbreak, the index case was not a healthcare worker, all the following cases in blue are all healthcare workers, doctors or nurses, and everyone bordered in red died, so Be a healthcare worker Health in an epidemic or pandemic can be a dangerous occupation.

Epidemics cause substantial panic and have substantial social and economic impacts, very often disproportionate to their actual medical importance, so take several of the recent epidemics and you will recognize. Many of the newspaper front pages involved in these issues tended to dominate the news for very long periods, even in countries that had almost zero chance of significant transmission, leading to the UK. Take SARS as an example between November 2002 and July 2003, the SARS outbreak that dominated the news for quite a long period of time caused just under 10,000 cases and just under a thousand deaths in 37 countries, which is obviously a substantial tragedy for individual families, but this is a small effort to eliminate this outbreak for which we know the details.

As noted by the World Bank, it probably wiped out around $40 billion from the global economy because it shut down airlines and created panic in Southeast Asia and Canada, a massive flu pandemic would be much larger than that for many factors and no doubt. , one of them has a really serious little impact, so it can have a very big impact on society, even if they are relatively less important from a medical point of view. The first question I am invariably asked by ministers is why we can't predict epidemics and prevent them before they happen. The beginning and the answer is that they come from almost every direction predicting and trying to prevent epidemics before they start.

X Stream Li is difficult and many people have tried and many people have failed and this is really because the vast majority of new epidemics come that are new to the world come when a disease that is in an animal species jumps to the humans and I just took some animals here these friendly fruit bats source of Ebola this gentleman here or one of his relatives source of HIV nurse in the south and in the Middle East, the Mexican swine flu, which many of you will remember, and BSE , so in the vast majority of new pandemics that are new to the world, animals are where they come from, but yet, being humans, we tend to blame Furness and sometimes, Unsurprisingly, for For example, when syphilis came to the UK we called it French smallpox, Neapolitan smallpox and Spanish smallpox, depending on who we didn't like, most of that time people were talking about the English sweating sickness etc. and the flu Spanish, etc., and blamed. foreigners is what we tend to do, actually animals are where they tend to start, but although the first reaction is almost a lot of panic, epidemics can actually be addressed systematically and the rest of this talk is about how systematically you can going through a new epidemic and saying now, what we are going to do and how we are going to respond really depends on five things: the first is mortality or the severity of the disease; a trivial infection is probably not something that requires such a major response; the second question is: a treatment available and if not, can we find one very quickly.

The third question is is there a vaccine available and then two very important things that are more epidemiological but are actually the key to any epidemic where the answer to the latest things that a treatment or a vaccine is already available that is critical the force of transmission which is a mathematical concept but I am happy to say that it is incredibly simple and the route above all the route of transmission the route of transmission is the key to

control

ling an epidemic just before I Let's get to the main technical part of the chat. I just want to define three things: An endemic disease is the background rate of an infectious disease and make these definitions because I will be using these terms repeatedly and I want to be clear what they mean. it may be zero, so an epidemic may be monkeypox, a relatively small number of cases, but the normal number is zero, or it may be a fairly high number, which actually has a spike if you think about, for example, the pneumonia, pneumonia is endemic.

The disease in the UK kills a lot of people, probably around 29,000 people a year on average, but we don't consider it to be an epidemic because it's just there all the time, whereas we're much more enthusiastic about epidemics that kill much smaller numbers. of people, so endemic diseases can be quite serious and I will talk for most of the rest of this series about endemic diseases and then there are outbreaks or epidemics and that's when there is a peak of diseases above the seasonal background,may be a small peak due to seasonal background. It's almost zero or it could be a big spike and the terms are a little slippery, but generally people understand that an epidemic means a fairly large outbreak and an outbreak means a geographically localized one, so I'll use those terms that way. you know you can have a little bit of iniquity when I use them and finally a pandemic is an epidemic that occurs all over the world or at least crosses many international borders and is officially declared by the World Health Organization, so the first of The things I said are the important thing is mortality and mortality varies very substantially according to the different epidemics, but, of course, it has to be to have an impact, it has to be the mortality multiplied by the number of people who actually suffer from it, so let's start with a recent Ebola epidemic: the mortality of an F Adem ik ball was between 60 and 70 percent, so if you have the disease, that was the probability of dying from smallpox, the main form of smallpox, About 30 percent of people would normally expect to die, think about the 1918 H1N1 flu pandemic that only had a mortality rate of about 3%, but because it affected many millions of people, its impact on society was in reality considerably higher and finally I ruled out a disease that actually started here in the UK, knee variant CJD that came from PSE that had a hundred percent still has a hundred percent mortality but of course relatively small numbers, so so the mortality rate is very important, but it may not just be a function of the disease, so also mortality may vary depending on nutrition. state by ethnicity, age or a variety of other factors, so if we just take measles, a disease that many people mistakenly think is a fairly trivial disease in measles epidemics in Africa, for example, when they occur, they usually there is still a mortality rate.

Between five and ten per cent of all children who contract measles will die from it, it is not a trivial disease, there may be up to one in ten in measles, on the other hand, it is endemic in the UK because the people are well nourished the mortality rate from measles is around one in 5,000 it is still not trivial but it is very different, let's say that mortality can vary even within the same disease, this is clearer if we look at the influence, look at influenza and here what I've done is a Table 2x2 table comparing barre3 influenza outbreaks and the key thing to understand is that transmission and mortality in influenza are largely unrelated to each other, so some epidemics like the Spanish flu pandemic have a fairly high mortality of 3%, but not massive but massive impact because it had a very high transmission, then there is the recent h7n9 avian influenza which has relatively small numbers, it is not very transmissible, it is very possible You might have to do dabiq resuscitation math to catch this from a bird, but if you catch it, your chance of mortality is 30%, so the flu can kill well over three percent of those who catch it, or then there is the swine flu pandemic of 2009, which had a mortality of 0.3%, that is, one tenth of that of the great flu pandemic of 1918, but it had very large numbers, so these two do not They are largely related and I think one point I would like to make with this is that the Spanish flu pandemic is not the most dangerous a flu pandemic could be, but it could actually get worse, so think about that when you feel crying, even if it's not possible to

control

an epidemic, stopping people from dying, as it should be, and you can usually do in most pandemics, is something that substantially reduces the chance of people dying.

Once you've figured out what the cause is, there may be some specific things you can do. do it if it is a bacterial epidemic for example you can use antibiotics and most new bacterial infections especially in animals will be sensitive to antibiotics not everyone can use antivirals if they are viruses but antivirals are in a much earlier stage of development, so most viruses. we don't have an antiviral that works for the cranky ones that we know works for them is a parasite, you can use antiparasitics, etc., and then there are some treatments you can do that are specific to the disease but aren't actually designed to kill the infection. antibiotics, antivirals and a good example of this is vitamin A, which in the case of measles will greatly reduce mortality, especially in malnourished children, so it is not an antiviral drug, but it is a drug that has a very great impact on reducing the disease and then you can have some Secondary things like antibiotics and severe flu don't stop the flu, but they prevent people from developing pneumonia, so you can find ways to counteract the death of people even if they get the infection and of course there are always standard medical treatments with ventilated fluids afterwards.

The question why we didn't predict this and why we couldn't stop it before it started, the next question that policymakers will ask us recently and that I suspect they have asked since Jena produced the cowpox vaccine to prevent smallpox is : when can we get a vaccine? The answer is whether the epidemic is with the disease for which we already have an effective vaccine, as long as the rest are available, so let's take some examples: yellow fever, measles, polio, smallpox, these are all diseases in which the vaccine that we have is very effective if If we have an epidemic of any of these we should be able to stop it on the occasions when we can't and as there was some recent smallpox I saw some loot yeah so there will be some recent outbreaks of fever yellow or don't look in the newspaper.

The idea of ​​smallpox is the yellow fever epidemic and it has happened in part because the world has a global shortage of yellow fever vaccine, but they don't know how to make it, it's just that we have a manufacturing problem, so you can have some diseases where there is a variant of a known disease with a known vaccine and the classic one for this is influenza which, as everyone knows, must be reformulated every year to comply with the current form, if a pandemic comes, you will not know what the current form and It usually takes at least four months between the time the pandemic begins and the time an effective vaccine can be obtained; that is the minimum preparation time, it could well take longer or new diseases, even if it is possible to receive a vaccine, a vaccine will generally take years, so it is unrealistic to think that in the first phase of an epidemic it will be possible to control it with a vaccine because that is simply not biologically or clinically feasible and for many diseases we have tried very hard for decades to obtain vaccines and so far we have not managed to obtain vaccines that are more than partially effective, good examples are HIV and malaria, so Vaccines have an important role, but the idea that they will be the solution to all epidemics is optimistic if it is done. have that vaccine, however, there are several ways to use it, but one that everyone would think of is to vaccinate the entire population and this will work if you have a highly effective vaccine that has few side effects, it is easy, ideally, it is cheap and this It will provide some degree of immunity for the entire population, even those who are not vaccinated will be protected by the fact that the people around them are vaccinated.

It was the so-called immunity, but there may be other groups in situations where it is not available. We don't have that type of vaccine in large enough quantities and in that case there are two other approaches you can take: you can vaccinate high-risk groups so that the people who you think are most likely to get an infection and then transmit it could be, for example, health care workers, it could be, for example, sex workers, sex workers, if it were a sexually transmitted infection and the third approach you can take, which is probably the least intuitive but is actually extremely effective in the right setting, is what is It's called ring vaccination, this is where you find a case and then you vaccinate everyone who has been in contact with that person and generally everyone has also been in contact with those people.

This was effectively tried in a smallpox eradication attempt and we are using it again now in the most recent is an outbreak of voters, so if that depends on the vaccine you have, act extremely quickly if you have a vaccine that will take three months to take effect, it is clearly unlikely that this approach will be effective, the final concept is the idea of ​​transmission force and this is the mathematical part that I am going to do in this talk, but it is simple, the key to understanding transmission of force events, this is the central understanding of epidemics, if you have a disease that on average is transmitted from person to person to person on average that disease is stable in the population that has a force of transmission an R of one if one person gives it to two people he gives it to four people he gives it to eight people and so on, that has an R of two and that disease is expanding exponentially and for those of you who work in the city, This is an aggravated problem, expect this financial increase over time, that is what causes epidemics and if the R is below one, let's say it's point five, ten people give it to five people, they give it to 2.5 people and that disease is on its way to disappearing.

The key for Ana to controlling an epidemic is to try to figure out which one it is and put it under one once it is under it. 1 the epidemic is going to die and to say that understanding this number is essential for eight days and, in fact, a large number of infectious epidemics are quite low, ours is quite close to one, so the idea of ​​​​reducing them to less than 1 is completely biologically feasible. So if the epidemic dwell, for example, was between 1.2 and 2.5, a flu pandemic probably between 2 and 3, polio, a little higher for marijuana, between 5 and 7, HIV 2, etc., of course, there are some diseases where the R is very high and in particular, I point out one area in Africa where the R for the disease can be over a hundred, getting it below one is going to be problematic and, along with this, it's not exactly the same as the idea of ​​doubling time, how long does it take? each number of cases doubles and that is a combination of the cases and the frequency with which the cases are transmitted, but for the rest of this talk I am going to talk about the route of transmission because this is the key to control and there is basically five. and what you can do to control an epidemic depends on the transmission route it has, it has air routes with influence and examples of them are influenza MERS and SARS routes transmitted by food and water cholera typhoid BSC HCG CJD contact Ebola or Lassa transmitted by vectors that means that the insects Zika, dengue and plague would be examples or sexual, for example, HIV or syphilis.

Now, for all of these, generally you might have one predominant pathway and you might have a secondary pathway, but usually one pathway dominates and if you can control that pathway, the disease. can be controlled let's take some examples of a bowler it's a touch disease and most people know it so I'm just going to use it as an illustration despite the fact that actually if you have a bowler , even if you are relatively close to someone, but do not touch them, you are not going to infect them, so, for example, if the rector had Ebola, I would not consider him at risk being so far away from him.

Ebola managed to spread quite effectively through West Africa and modeling showed that we were soon going to have a disease that was out of control even though it was relatively difficult to transmit by touch, so the situation at the beginning of the Rosetta disease epidemic with high mortality very few non-vaccine medical countermeasures, although there was animal data showing that vaccines could work with an R of between 1.5 and 2.5, we solved it fairly quickly and a while doubling period of approximately two weeks and the main route of transmission was touch. It's important to say that people were only contagious when they had symptoms, but they were still infectious after death, those are really critical points and what that meant, therefore, because this is a tactile disease, we had to perform touch interventions and we chose areas where touch was transmitted in hospitals and it was about controlling infections in hospitals. around burials because people are contagious after death and they were touched after death so it was safe burials safe burials were easy safe burial was acceptable to the family much more difficult so that was a key factor in reducing community transmission by basically finding people with symptoms and isolating them andthen widespread isolated social distancing, for example encouraging people not to shake hands when they meet, pretty simple things that would make it less likely that they would touch someone who was contagious at the time and what you found out was that Sir Leone is contagious if you put.

All in all, you are in a situation where the AR started to fall quite quickly, so the major interventions started in August and September and you had an AR of more than 1.5 and the AR started to fall steadily now, Of course, as long as it was above 1, the number of cases continued to increase, so one of the things that happened in this epidemic is that people around October said this was not working because the number of cases was increasing, but actually if you look at the AR, you could say it was going down and we could see that it was going to cross a roundabout in December and at that moment you reach the peak of the epidemic and it happens so you used our to see that your interventions were going to be effective as I already said before that it was a very heavy burden for health workers and that meant that in our first interventions we were between a rock and a hard place.

Health care workers were absolutely essential, but they were also the most vulnerable people. epidemiologically early intervention, but if you put untrained people in our hospitals who don't know how to use personal protective equipment, you end up with a situation where about eight to ten percent of the health workers who initially The cases they treat get Ebola and about 80 percent of them died, so there was a real trade-off between getting in early and controlling the epidemic and essentially throwing people into a very dangerous situation and that tension had to be resolved. Now we have a second outbreak this year. of Ebola and, interestingly, the way we have to deal with it is quite different;

The most positive difference is that we now have a vaccine and we are now applying a ring vaccination that was not available before and thanks to the work that was done. In the first epidemic we were able to move on to this second one, but we also discovered that the social interventions we used have become much more difficult. Ebola in this area is politicized. It is a very difficult political environment. It is a very unstable group area. Many armed groups substantially distrust the government and I think it would be too early to say that we have this outbreak under control at this time.

The second important pandemic to consider is the HIV pandemic. This is a sexual disease. I'm going to go and take an example of each of the routes and you can go to the other one after the 1918 flu pandemic, the other really important pandemic of the last hundred years, about 35 million deaths to date, this It's a really serious disease and again, if you look at the spread in Africa that happened from 1984 onwards, until 1999 I was working in this part of Africa in 1999 and seeing a third of people my age die from HIV was an experience. quite depressing, including many of my friends and colleagues, you know, a fairly rapid spread across the continent, so the beginning of this epidemic which was recognized in 1981, even from the beginning, that we realized that There was a very high mortality, we had no medical countermeasures, very few, we had no vaccine, the R was approximately 2 to 5, but the main route of highly variable transmission was sexual, which was resolved quite early. but there was a major secondary route, there were people sharing IV needles, basically sometimes people using recreational drugs, but also healthcare workers using the same needles for many people, so it wasn't just drug users, intravenous drug users and, more importantly, people. infectious when they had no symptoms there was no way to know that someone had symptoms and would be infectious for many years, completely different to the Ebola situation, so in the absence of a vaccine, a drug or anything else, all we had was behavior. change and there were many approaches to trying to change sexual behavior.

I have to say that a large number of them were highly ineffective, including those that you just look at and think what you're trying to do here, so changing behavior is difficult, but for a sexually transmitted infection it was clearly absolutely essential and a One thing we managed to do was get people to know their HIV status, but that took a long time and, alternatively, we have to consider those on intravenous medications, which also on behavior change, but in It wasn't really about trying to stop people who were addicted to one of the most addictive drugs ever known, heroin, from becoming addicted, that just wasn't realistic, so I had to say don't share needles and it was quite a difficult political battle to fight because the lost people wanted to keep saying: well, you know what you expect, just stop using this drug, obviously they had never been addicted to heroin, so the approach we had to move to on par of behavior change was medications to treat people and that has really been what has changed the course of HIV, it has not been a preventative approach, although that has been important, but medications to prevent people from dying.

The first antiretrovirals appeared in 1986 and failed rapidly within weeks, so taking them actually extended to a shelf life of no practical purpose for a long time, we entered the proper antiretroviral era around 1996, but they were very expensive and clearly not affordable in the part of the world where the vast majority of infection was that medications are now widespread, but still less than 50% of people who have HIV take them, but there are now very good prospects for people who know they have HIV and that they are effective medications, which is why we have not managed to stop HIV.

The epidemic, although it is receding, what we have achieved is to move from a situation in which everyone was dying to a situation in which, if almost everyone who uses drugs lives a good and full life, we have looked at vaccines and medications to prevent HIV, this has been a huge investment in HIV vaccines over many decades and we have yet to get a vaccine that is close to being rolled out in the general population, which shows that sometimes that seems to be relatively simple from the Biological point of view, sometimes it is actually not what can have an effect on the epidemic.

However, the fact is that people who are on treatment are much less infectious and therefore widespread use of treatment if people are treated early may lead to a reduction in the bitter epidemiological debate about how long people should be on treatment. on treatment for this to be true, but clearly it is going to have an effect and medications can now be used as prophylaxis in high risk encounters, so what we have with HIV is that the incidence in terms of number of new cases is decreasing, but very slowly there will still be many. of new cases of HIV by the time I retire and probably by the time I die, but the number of people dying from HIV has been greatly reduced, so we have tackled this epidemic by treating cases of high income.

New cases are starting. fall, but we must be aware that eight more people, around 1.8 million, were almost infected with HIV last year, so this is not a disease that has disappeared by any worse means and we are not going to get rid of she in If we get a curative drug that we not only have or a vaccine or both, and I think both are far away, these are some interesting parallels with syphilis in the United Kingdom. Syphilis entered the UK in the pre-era era. Since the birth of Sir Thomas Gresham, almost exactly at this time, a hundred years ago, there was a royal commission that asked how many people in London have syphilis and the answer was 10% of men.

I just look around me and think about that fact that kills. that epidemic was the introduction of penicillin and again the treatment was what really led to the outbreak stopping, although there is still syphilis, obviously now the third main route of transmission is vector borne epidemics which are now rare in the UK, but they remain a major global risk that they used to combat. Of course, it is extremely common in the UK, so vector-borne epidemics is a stage in which this university was founded. Epidemic typhus transmitted by fleas. The plague is also transmitted by fleas and malaria, especially in the less healthy parts of Essex.

It is transmitted by mosquitoes. Actually the UK now. has very few vectors with epidemic potential, although they can transmit some diseases and the most important are ticks and potentially mosquitoes, so there are no major transmitted diseases at this time to humans, but vector-borne epidemics worldwide are extremely common. Mosquitoes are the main culprit but Sand Flies, Fleas, Biting Flies, Ticks and Mites all carry different infections so there are a lot of vectors out there and the question is where do they live Professor thanks to Frank Cox , who was previously an aggression teacher. The physics

prof

essor is a real expert on mosquito ADEs and I have stolen a couple of slides from him just to make it clear that mosquito ADEs are an example of a mosquito that can transmit many diseases, so you can transmit yellow fever and pass.

I am dengue and pass. Jack King Jr. for example, and it has spread quite a bit because it is very well adapted to living in peri-urban environments. This, for example, shows the map of the transition of dengue across the Americas over three decades because this mosquito is ideally adapted to the environment. and a recent example was Zika, back on the front pages, a disease that had existed in Africa since at least 1947, when it was first described, probably much longer than it managed to hitchhike across the Pacific to Latin America and established a very important epidemic in Brazil, which again many of you will remember.

This is what caused very small heads in some newborn babies, which almost certainly caused very substantial neurological damage, and many other babies may well be harmed. of which we still don't know what they found was again a very small number of people who were born babies with very small heads and then in 2015 a large increase in these cases and extremely good epidemiology by Brazilian scientists quickly discovered that there were a link to Zika. which was by no means obvious and therefore we had a significant epidemic with high transmission in Brazil, about 12% of pregnancies in the first trimester in infected people would go on to have micrographia and probably more of them would have neurological diseases at the moment.

It is a major infection, there are no medications or vaccines and although we know about the mosquito we don't have very good ways to control it, it is much more difficult to control than other species of mosquitoes, although control measures are available and are improving and there was the possibility of a Also the sexual route of transmission what we had was the peak of the epidemic and then it started to decline and it started to really decline for two reasons, one of which was that the climate and the rainy season changed, which made it less easy. to transmit there were fewer mosquitoes for practical reasons and the second was that a much larger proportion of the population became infected and then became immune to the infection.

It's a combination of those two. This was lucky for many people in Brazil. Actually, it was also lucky for Rio. epic Rio Olympics that might otherwise have been significantly affected by this disease, but the question after this outbreak in Brazil was where else could it go and the answer is, in theory, anywhere the main mosquito that transmits it in a DS, and this is a map of where it is found and then it has a somewhat close relationship with something called ATS albopictus. It is unclear how good this mosquito is as a Zika transmitter. It's still not very clear how good this mosquito is, but this one has an even wider distribution in areas that are a little bit colder because they can overwinter under certain circumstances, what that means is that this particular vector, the ADEs Egypt II, is not well suited to Europe, Europe, but this particular vector, Aedes albopictus, is gradually spreading across Europe and these are maps of where.

Other DS images could potentially be because the climate is right for it in the coming years, so there are large parts of Europe, including small parts of England, that are actually able, in theory, to maintain populations of these vectors and, therefore, potentially maintaining transmission. of an epidemic, so we have had a touch of sexual and vector transmission.Now I'm going to move on to water and waterborne foods. I'm going to be relatively quick with this because it is a disease that should not exist, cholera and there is Right now there is a massive outbreak of cholera in Yemen and over the last year there have been 1.2 million suspected cases of cholera and more than 2,500 associated deaths, 29 percent of them in children under five years of age.

Look at that and cry because this is a man-made outbreak. epidemic currently there are around 100,000 cases per week of cholera in Yemen we now fully know what to do with cholera it was one of the first diseases properly after I researched logically and it was actually its route of transmission was demonstrated very clearly first here in London by This Gentleman John Snow did two things, one of which was some epidemiology that no one really knows, where he mapped different water companies and their cholera rates, but the second, which people tend to know, is that he mapped outbreaks around the different pumps in central London and showed that they were mainly focused on one pump in Golden Square or Broad Street and, quite theatrically, he went and removed the PAMP pump handle from that pump to make sure that no one could use it and as a result of the treatment. water and stop the use of the pump, the cholera outbreak stopped, so we know what to do about it since 1854, unfortunately, the reality is that epidemics have always followed and always will follow war, civil unrest and disasters, what people would call backward development and There are many reasons why these vaccination programs, housing, water sanitation are destroyed and therefore all the things that have been rebuilt are like defenses that are removed and therefore Therefore, all enemies such as typhus and cholera resurface and do so as an absolute as the night progresses.

The day after wars, rapid movements of exposed populations also occur, exposing people who are immune to a disease, so nanami becomes a disease in a risk area, and people move to lands marginal because they have been displaced where there are many vectors that can pass. Things happen and there are breakdowns in social norms, so there are increases in sexually transmitted infections. Basically, war is an absolutely perfect way to cause an epidemic of any kind. Not all food and waterborne epidemics are caused by war. They can even occur in most cases. peaceful and prosperous societies, but usually only in very limited circumstances.

A recent example, at least one that many people in the audience will remember, was the CJD epidemic, new variant of BSE, that started here in the UK and the reason this was able to spread is very strict public health things that They protect without most people knowing, everyone is protected by a web of rules, regulations, inspections and other paraphernalia that prevent foodborne and waterborne infections from occurring. This is an example where the usual barriers did not work. It is not destroyed by cooking and therefore we had to remove it from the food chain, leading to a situation where over 180,000 cases of BSE occurred in livestock, leading in due course to the at the moment 178 cases of the new variant of CJD, but the numbers are gradually increasing. there was a mass slaughter of livestock, the removal of horrible and neurological tissues changed the diet, so we were able to respond to this, but nevertheless it shows that even in highly developed societies you can still contract diseases through food or by some route important. but I'll end in terms of the illness that I will go through before rounding up a few points with pandemic influenza because this is still by far our biggest known epidemic risk.

It is the national government of the United Kingdom. The risk register maintained exceeds any other risk facing the nation and for very good reasons, the airborne risk is indiscriminate, it is much more difficult to interrupt other routes of transmission, you know, prevent people from touching each other or other change of sexual behavior can be difficult, it is actually much more difficult to stop them. breathing in an environment surrounded by people the spread of an influenza pandemic is really fast, as I demonstrated in some of my previous slides, the enormous speed at which the 1918 pandemic occurred exactly one hundred years ago and a very high proportion of the population would be affected in Once, if you think about a situation where about 20 percent of the population was actually infected, most of those who are not infected would probably be taking care of the children, the grandparents, the friends who had the disease, then we take, let's say, we eliminate fifty percent of all the train drivers or supermarket labor market workers, all the nurses, all the people who run the banks, and just think about what that will do to our society .

The reason this is a really serious potential threat to the UK now the question is not whether we will have another pandemic, we will have another man to do it, it is really a question of when and how serious was the last pandemic we had in nine and 2009. The value was actually quite low, but they were still very substantial numbers and, just looking at it again, just looking at the velocity of this, this is around April 6, where it had spread to this is around April 20 , in May and in July. That is the speed with which it was transmitted throughout the world, there were between 40 and 19 million cases of this pandemic and because it was of low virulence there were only between 8 and 18 thousand deaths, but this was about to happen, This could have happened.

It was much worse and of course there are wide estimates about the numbers. The peak transmission of this occurred incredibly quickly. If you look at the UK figures, this shows how quickly it arrives, in a matter of a couple of weeks. this is not something one has time to properly prepare for, officially there were 457 deaths in two waves, the numbers were almost certainly a little higher than that. We had a vaccine available, but long after the spike, so it wouldn't have helped us if this spike had been massive, the drug use was very controversial. I'm not going to go into the prophecy.

I could ask certain questions if you are interested, they are more helpful. I have taken them early, but the most important thing is that all drugs are a single mutation of the virus. was enough to render the drug ineffective and this happened quite early in the epidemic and it requires a lot of unavoidable interventions, such as screening at airports and travel bans, which are completely useless, it is almost completely useless as it does not do no difference and close schools, which has an effect, but at a cost, for children's education and for people who are working, who then have to stop working to be able to take care of the children at home, so This is going to have considerable problems that we can certainly put the basic elements in place to try to address an influenza pandemic, but we have to be aware that this would be chaotic and large and no plan survives contact with the enemy, so mathematical models that we implemented were good models that will help us. at the beginning of a pandemic to determine how quickly it will move where it will go global virus identification networks to determine very quickly what the virus is and where it comes from which we seem to have decided in advance, although there is much debate about which parts of the health service would you close first to protect the rest because we have to do that to determine how serious it is, we have figured out how to optimize vaccine production, but we all know that four months is the absolute minimum and if we look at the speed of that transmission , the vast majority of the first wave would have done its damage long before we had a vaccine and we have a stockpile of antivirals, which is much better than nothing, but it has some problems associated with it, so to bring together some of the issues About this, the first reaction was to be careful in an epidemic, even a fairly small one, usually it is panic and, in fact, for small epidemics, panic is what causes the most important problems, except for a large epidemic. is really big and some of the examples are given, particularly the 1918 flu pandemic and HIV, very big how we respond to them must depend on the mortality and the severity of the treatment, what we have, what we can adapt and what we can develop vaccines, but for most new pandemics we are not going to have a vaccine or we are going to have it quite late a force of transmission how close is the r21 that is really critical for what we do and then, above all, determining which is the transmission route because even if you don't know what the infection is, if you know how it is transmitted, you can come up with some logical countermeasures once we have finished the route, we enforce the transmission, we can make changes and I have put them in a place just for emphasize a general point for a bowler was behavior change, the former isolation of cases and now a vaccine, but much later for HIV behavior change and more than a decade later, drugs, cholera, vjd, safe water, safe food and the absence of war and influenza vaccines, medicines and social organization in each of those lines, a lot of this has to do with the organization of society and behavioral change , not with drugs, vaccines and other high-end medicines, so society changes the normal behaviors that people normally do by shaking hands and hugging. a friend who has sex with his regular partner eating a meal drinking these are normal behaviors, you need to get people to change them in epidemics because that will probably be the only way you will be able to overcome them and therefore you need to know the path, so although overall infectious diseases, these dotted lines have been significantly reduced in all high-income countries as a cause of mortality compared to cardiovascular diseases and cancer epidemics remain a very important threat even for higher-income countries and Certainly, in lower-income countries, Thomas wonders: infectious diseases dominated by medicine will always occur epidemics, but the risk is substantially lower and I think my central point would be that richer countries They are hardened against epidemics not because people deliberately design them that way, but because If you want to have sanitation, good housing, adequate food, clean water, if you have those epidemics, it is much less likely and this would be something that I am sure that Sir Thomas questioned.

He would have approved as financiers and diplomats of those he brings in. Priests and prosperity do at least as much as doctors and scientists to prevent future major epidemics, and since we are much more prosperous, I am happy to say that epidemics are much less likely, but they will still continue. Thank you so much.