UCL Minds


Transcript: Episode 2

How can we track the virus?

Vivienne Parry  0:08 

Welcome back to Coronavirus: The Whole Story, the new podcast from UCL. I am Vivienne Parry. I'm a writer and broadcaster and a UCL alumna, and each week I'll be talking to UCL researchers and staff about Coronavirus. In each episode of this podcast we'll be considering a different perspective of the Coronavirus pandemic, and learning from the wide range of disciplines here at UCL.

Last week, we took a look at Coronavirus and intensive care. For this week's episode we'll be a bit closer to home as we talk to Professor Andrew Hayward and Dr. Eleni Nastouli about social distancing and current efforts to monitor the spread of the virus.

So let me first introduce our guests Professor Andrew Hayward who's director of the UCL Institute of Epidemiology and Health Care, and UCL professor of Infectious Disease, Epidemiology, and Inclusion Health, he's leading on Virus Watch - a new multimillion pound research effort to measure the spread of Coronavirus within communities and how this spread is affected by social distancing. Dr. Eleni Nastouli is assistant professor at the Institute of Child Health and clinical lead of the Department of Clinical Virology at UCLH. Dr Eleni Nastouli is leading on SAFER - evaluation to inform response study. And that's going to involve monitoring the behaviour of frontline staff to identify their risk of infection and determine how to reduce this. So let's start with you, Andrew.

First of all, Andrew, tell me how do we know how many people have been infected by Coronavirus?


Andrew Hayward  1:56 

I'd say the answer at the moment is we is we don't. We have some estimates that based for example, on if, if, for example, we make assumptions about what the case fatality rate is in COVID. And then we think about the number of deaths and multiply backwards, we come up with some calculations. But of course, that's already dependent on knowing what that case fatality rate is, which we don't have good measures of, I think, really, the only way of knowing is to directly measure it. And I think there's two ways of doing that. One is to go out into community settings and follow people up and get them to report anytime they have an illness and to test them anytime they have an illness that might be COVID to see what's the incidence, so how common new cases are. The other way of measuring it is through these antibody tests that you'll you'll likely have heard about, which really are designed to measure whether or not you've been exposed to Coronavirus, had an infection and developed antibodies to that infection. And so if we test the public, we can potentially measure that.


Vivienne Parry  3:19 

So you've got a ‘have I got it test’, which is based on looking for the viruses, genomic material, and you've gotta ‘have I had it’ to test which is looking for antibodies. But of course, what we're thinking of with Coronavirus is that there are lots of people who don't have perhaps any symptoms at all who don't know that they've got it or had it. So what are we doing about them?


Andrew Hayward  3:50 

I think that's absolutely right. So and I mean, I think those really divided into two groups. One is where you're thinking about people who just have Have a really mild illness that they wouldn't normally think anything of, you know, like that's, you know, similar to a common cold or, or, or that sort of thing,


Vivienne Parry  4:13 

or maybe just feeling a bit rough one day.


Andrew Hayward  4:16 

Quite possibly, yes. And then, and then you, you probably got another group who are who are not developing any symptoms at all, like you say, and we really don't know the relative sizes of these of these infections. And, and, and I think that's, that's a lot of what virus watch is really about trying to measure those different sizes of the the, the first one measuring the, you know how many people are real, but that we didn't know about is sort of more straightforward if you like them, measuring how many people have been infected, but never had any symptoms. But we're certainly seeing quite a lot of evidence from a number of settings that, particularly in outbreak settings in institutions that, that within those settings, you can get quite a lot of people who appear not to have any symptoms, but are still infected with COVID.


Vivienne Parry  5:22 

And actually how many people have had it had enormous implications for the measures that we take, but also things like the case fatality ratio, because if you think about the number of people dying, and you're thinking only, I mean, let's say 100 people get it and you know, they've got it and one person dies, then that's one sort of case fatality ratio, but if actually, you know, that is when your your figures reveal or testing reveals that 1000 people have actually Had it and any one person has died, that has dramatically altered that case fatality ratio.


Andrew Hayward  6:08 

Indeed, and I think we need to be very careful when we're talking about case fatality ratio is about what we're actually talking about, you know, are we talking about the the number of deaths divided by the number of infections, whether those be symptomatic or asymptomatic infections? Are we talking about the number of deaths divided about by the number of symptomatic infections? Are we talking about it divided by the number of laboratory confirmed infections, and you'll come up with completely orders of magnitude different estimates depending on which one of those you choose.


And I think that does.


I mean, it has implications both for you know, how we communicate about the virus and the consequences of getting infected. I think most people greatly overestimate their risk of becoming very, very ill.


Vivienne Parry  7:06 

Please about 30% of people think I get it, don't they?


Andrew Hayward  7:10 

Well, I mean, I think it's maybe not so much the issue of whether people will get it or not, but the issue with how ill people think they will get if they get it, and the fact is that for the great majority of us, it will be a relatively mild illness or possibly, and we don't know the size of this yet, possibly also an illness, no illness at all. And so that that sort of, if you like, potentially changes one's perspective on personal risk. But then again, we still know that in some groups, particularly the elderly, and those with chronic illness, then the risk of any infection turning into a much, much more severe situation is is very, very much hard.


Vivienne Parry  8:01 

So how is virus watch going to operate? How is it going to give you this crucial information?


Andrew Hayward  8:10 

So, the way that we're working in virus watch is really to try and recruit a very representative group of the population from across the country. We're doing this through postal recruitment of more or less a randomly selected sample across the country to be representative. And we'll be inviting them first of all, to sign up to an online survey which will allow us to collect a lot of background data about the participants themselves and the other people within their household. So that will include you know, their medical history and and a lot of social factors as well what sorts of work they do these sorts of things and then everybody will be asked to record all of the symptoms that they think might be related to COVID as we go forward following people up over a year, and we'll be contacting them on a weekly basis to ask them to record those onto our online survey. Also for a subgroup of those participants of around 10,000. We'll also be asking them to submit Nose and Throat swabs taken during the early part of any illness, so that we can look for the virus in those Nose and Throat swabs.


Vivienne Parry  9:40 

And there's an issue there with the nose and throat swabs. Isn't that because taking your own throat swab is a bit like trying to poke yourself in the eye with something it your your whole reflexes are set up to avoid you doing such a thing to yourself. And so how confident can you be that people are taking their swabs in the right way?


Andrew Hayward  10:04 

Well, we do. We will be going into quite a lot of detail and providing video instructions for example about how to do this. We've got some researchfrom within influenza that suggests that this is not a bad way of identifying viruses compared to healthcare worker-taken samples. But yes, you're right, we will lose a little bit of accuracy in our tests. This is also why we were wanting to take them both from the nose and from the throat. So yes, it's one of the things that we will need to consider within it.


Vivienne Parry  10:46 

So Andrew, the implications of this research are profound, because if the virus is much more widespread, and far more people have been infected than we think, then that has implications for lockdown for social distancing, and for many other aspects of our life post COVID.


Andrew Hayward  11:09 

I think that's right. I mean, a critical part of the argument about how long this is going to go on for how restrictive we need to be is, is really about how many of us have already had this and how many are immune. And we, we think, from the best of our understanding so far that maybe that in, say, a city like London that's been severely affected that, that maybe we might be up to say, 10%, possibly 15% of people but we but this is very much a guess at the moment, we need to measure this.


Whereas if we're, if we're wrong on that, which we could be because we haven't measured it, there may be that many, many people have been infected. And that that's something we need to know very quickly.


Vivienne Parry  12:05 

Because what would it mean, if you didn't discover that many more people had been infected in terms of the kind of measures that we're taking at the moment?


Andrew Hayward  12:15 

I think it would, in my mind, it would be that would be a good thing, because it would indicate that we're further through this crisis than we might otherwise have thought.


I think one of the key concerns is that even though we've seen all of these very high levels of death over recent weeks, and that we still have a long way to go in terms of the proportion of the population that are susceptible to COVID and of course, it's a much higher proportion of people have been infected than we think. Then it may not necessarily it may follow that a much higher proportion and now immune than we think.


Vivienne Parry  13:15 

You're listening to Coronavirus: The Whole Story - a podcast brought to you by UCL Minds. There's a question about Coronavirus that you'd like our researchers to answer, please email us at minds@ucl.ac.uk. And now we've been joined by our other guests today Dr. Eleni Nastouli, so Eleni, of course the people on the front line, they are really very vulnerable indeed. What's the picture? Is that the case? And how are we going to find out?


Eleni Nastouli  13:48 

Thank you. And thank you for inviting me in the webcast. So yes, this is a concern. We don't and actually this is one of our aims with our study to clarify what that risk actually is, and this is something we will measure. And I'm very happy to say that we will have preliminary results, hopefully next week or beginning of the week after. And, yes, the concern is that they are potentially highly exposed in terms of the frequency of the exposure and the virus load, if you like, or the virus inoculum as we determine we use they have been exposed to. And we actually want to know much better about that and how much the level of the protective equipment that we use in the hostile environment actually protects healthcare workers. And how does this compare to the community rates of infection? I think this is absolutely what we want to explore and know more about. But yes, the concern, obviously, is that and I must say that I'm taking very seriously the concern and the anxiety, that frontline health care workers have at this date.


Vivienne Parry  15:04 

I mean, we've seen some initial research, but which has been quite reassuring that people in backroom roles in the NHS have not dissimilar rates of infection to people on frontline roles. And just tell me a bit more about that viral load because we we hear a lot about that. I guess that people who are the most exposed to the highest amount of virus perhaps if you're trying to put in a breathing tube for a patient or something like that, are the ones who are most likely to pick it up or isn't that the case?


Eleni Nastouli  15:38 

I my guess if you like and educated guess if you'd like is that


but we It remains to be seen in front line and highly exposed healthcare workers is that actually because of the use of protective equipment and the precautions we all take in these highly exposed areas is actually I expect it to be similar, if you like, and that we are actually with the with the measures that we're taking in for frontline staff at the moment, we are succeeding in protecting them and that we will see similar rates of infection. That's my guess at the moment, we were just waiting to see the results of our study and other studies. But this is what I expect them to, of course, would like to see


Vivienne Parry  16:32 

what kind of processes can be taken to help staff already. I mean, we've seen a lot of course about PPE and the kind of issues that are there. But there's also this idea of virus free zones. Tell me a bit more about that.


Eleni Nastouli  16:50 

Yes, absolutely. And thank you for this question, because I think this is the time that we should be very careful with language. And the semantics. And I think because of the how serious this infection can be, I think everyone wants also with a bit of optimism. And I noticed that on the language front we are, we like using language that brings a little bit of optimism. And I think consider the immunity passports or the virus free zones. I think part of this observation, my observation if you like, and I think this is the time we need to be very careful with this. We at UCLH, elected to use Covid protected areas rather than free because I think we don't want to create false reassurance to patients entering the hospital or healthcare workers in the hospital and actually try to be always vigilant to the measures we're taking in the health care facilities in terms of the risk. That's how I see that panning out to that we are looking at Covid protected areas where we are actually trying our best our maximum effort to keep that risk as low as possible. It will never be zero, but we have to do our best to keep it as low as possible.


Vivienne Parry  18:20 

Let me bring Professor Hayward back in again, because I want to talk a bit about social distancing and how that is impacting the risk of infection. How would you go about Andrew measuring the impact of social distancing on the spread of the virus? Because I think this is part of virus watch, isn't it?


Andrew Hayward  18:40 

Yes, I mean, I think I guess there's a distinction here between the the population level measures of social distancing that we've seen recently and, and obviously we've, we've had extreme social distancing amongst most groups over the last few weeks and we can see very clearly that as expected, that has dramatically reduced the transmission of COVID. So, you know, prior to those measures, we would expect every case to lead to two or three other cases. And since the introduction of those measures, we're now much closer to each case and infecting one other case. And so that's what's led to the overall decrease in transmission. I think the, when we want to try and get into a bit more detail of that, then we need to sort of understand, if you like, how individuals amount of social distancing and the amount that they're in contact with other people is related to their personal risk of infection. And so that's one of the things that we'll be measuring within the virus watch study, both through recording people pulls activities through more traditional diary based mechanisms, but also for those who agree to install the, if you like a GPS tracker app on their mobile phone that allows us to measure directly, where they're going and for how long, for example, and we can annotate that data to look, for example, did they go to the supermarket? How long did they spend there? Have they been travelling on public transport? And you can make these inferences from knowing their GPS location at a frequent intervals, which is what these apps now enable us to do.


Vivienne Parry  20:47 

You mentioned, Eleni, about immunity passports and this is an idea that's had some currency. It's certainly been going around, but it's actually I suspect quite difficult to enact in reality. What do you think about immunity passports?


Eleni Nastouli  21:10 

Yes, it is an area where we and others of course are trying to get this up and running that will give us some certainties around around that. There are difficulties in serology, serology is not something we would routinely use in clinical neurology, for other respiratory viruses. And suddenly we have this task of coming up with a sensitive and specific acids. To tell us more about this. I think the first step is to actually make sure that we give the right information at the right time to patients and staff about this. So the first very first step is to actually have it in RC where you are absolutely no the performance of how sensitive it is, how specific it is what the positive result means and what the negative result means.


Vivienne Parry  22:02 

And Elena, can I just interrupt and ask you to explain exactly what's meant by sensitive sensitivity and specificity? Because, yes, it always sure what that means.


Eleni Nastouli  22:14 

Of course, I mean, it's actually the certainty that we have around the positive and negative results in fairing on, on the patients of this stuff's status, whether they have the infection or not, and actually measuring idg antibodies is which is what the serology is all about and the immunity passport if you like, what if positive, the only thing that this tells us will tell us is whether someone has been exposed to the virus or not. Then the next step is to actually say, the presence of these antibodies, will you will they protect you from reinfection if you're exposed again, and this is something that we need to see in due course, as this infection and and and you know the waves of the infection infecting populations will go on and and that's why studies like ours I think are very, very important virus watch you know led by Andrew, and SAFER, because then we can longitudinally over time see the antibody levels in the populations in in healthcare workers and look at how likely is it then with a level certain level of antibody to be reinfected and then you can infer on immunity. I don't think that a positive antibody test at the moment, we're able to say that this will be protective of reinfection. We can always of course, from what we know from other spiritual infections and Corona viruses say that it's likely that you're protected for a period of time but what that period is, I think it's very difficult to say at the moment,


Vivienne Parry  23:57 

and of course, we're in a catch 22 at the moment, are we big Cause as we, as we're more and more successful with our social distancing, and the rate of infection goes down. So we find it more and more difficult to know whether those who have antibodies are going to be protected against future infection, because it's the future infection isn't around in such large quantities, then it will take them longer to be exposed to more new cases.


Andrew Hayward  24:28 

That's absolutely right. And I think this is so this is both a problem for assessing the protective effects of previous infection and antibodies, but it's also going to be a challenge when it comes to vaccine studies. So the lowering incidence of disease makes that more challenging. I think we will see further waves of infection. And so we need to be prepared to catch those waves from a research perspective. One of the things that we're doing in virus washes is really trying to get serological samples from the general population at the end of this wave of infection, so that then over the summer, and maybe of the winter, if, as we expect, COVID may start to transmit again more effectively, then we'll be able to relate those antibodies results to the risk of infection in the future.


Vivienne Parry  25:27 

Now, Andrew, you've been up close and personal to respiratory disease all your academic life. How does Coronavirus infection? How does COVID-19 compare to other respiratory infections that you've come across?


Andrew Hayward  25:46 

I think this is really, I suppose one of the things that got me interested in being involved in respiratory infections and particularly, influenza was the 1918 pandemic and realising the huge The impact of that on mortality in society and, and therefore being involved if you like in pandemic preparedness exercises, in case that happened and of course, I think we often fall into the trap. I think that thinking that this, if this was to happen, it would be a flu type of virus. And so the fact that it's a Corona virus is in, in some sense, unexpected. The Of course, we've seen other Corona viruses cause very, very severe levels of illness, but we've not seen them spread efficiently through the population. I think what this virus has is a really awful combination, if you like of an appreciable, a really quite appreciable mortality rate, particularly in vulnerable groups and Have a very efficient way of spreading from human to human. And, and it's those two factors that really, I think early on, made many of us very concerned about this, this problem and those concerns have largely been realised.


Vivienne Parry  27:22 

I want to close our discussion by coming to you both for a top piece of advice. So Eleni, what key bit of advice or tip have you got?


Eleni Nastouli  26:20

I think following the measures that were that that are taken, I think that would be my piece of advice. I think we all have to contribute in containing this infection and the disease that it causes. And I think that would be my very top advice to actually all of was trying to contribute to that and make sure that our fellow citizens and fellow colleagues that are more vulnerable are protected. I think that would be my main message. And the message about language - more about it. Yeah, I think we all have to be careful a little bit about the language that we use and be quite more precise when we talk about such important issues for people.


Vivienne Parry  27:10

Well, we'll include President Trump in that too, on the day that we were recording said that injecting bleach or disinfectant might be a good way to get rid of the virus. Andrew, what about you?


Andrew Hayward  27:22

Well, I think probably the most effective way of stopping this virus spreading is social distancing. And obviously, there's a big trade off between social distancing and the broader aspects of our livelihoods, economy, etc. We've got to find a way in which we can act as a society for an economy's still to function with. But with social distancing still in place, I think what's going to be particularly important is for those people who can just as easily work from home and I think many of us are realising that that's much easier than one might have imagined. should continue to do that. And I think the other my top piece of advice is really for those people who are most vulnerable with chronic diseases and, and the elderly. I think we need to be particularly careful about social interactions there. And I know this is a really, really tough thing, but I think over the next months and possibly longer, we're going to need to be very careful about that. Protecting the most vulnerable.


Vivienne Parry  28:33

Andrew Hayward, Eleni Nastouli in our studio. Thank you so much for coming to our podcast studio today. Our remote podcast studio I should say we're all in different parts of the country.

You've been listening to Coronavirus, the whole story. The episode was presented by myself Vivienne Parry, produced by UCL with support from the UCL health of the public and edited by Cerys Bradley. Our guests today were Professor Andrew Hayward, and Dr. Eleni Nastouli. If you'd like to hear more of these podcasts from UCL Minds, subscribe wherever you download your podcasts, or visit ucl.ac.uk forward slash Coronavirus. This podcast is brought to you by UCL Minds, bringing together UCL knowledge, insights and expertise through events, digital content and activities that are open to everyone. Hope to be with you again soon.