Speech: Chief Scientific Advisor and Chief Medical Officer briefing on coronavirus (COVID-19): 21 September 2020

Sir Patrick Vallance, Government Chief Scientific Adviser:

Good morning everybody. Im Patrick Vallance, the government Chief Scientific Adviser and Im here with Chris Whitty, the Chief Medical Officer and we wanted to give you an update on where we see the epidemic at the moment, some of the knowns and some of the uncertainties.

Let me just start by reminding you that this disease spreads by droplets, by surface contact and by aerosols. Hence the hands, face, space but also to remind you that the way that we reduce the spread is by limiting our number of contacts, by reducing contact in environments where spread is more likely. Those are crowded environments, indoor environments, poor ventilation. And making sure that we reduce the probability of coming into contact with anyone who is infectious and thats the importance of self isolation, keeping out of circulation if you have or may have the virus. May I have the first slide please?

I want to start by talking about the rise in cases elsewhere and what we can learn. Weve seen increase in cases across Europe, and here Ive taken examples of Spain and France. We have seen an increase in the numbers of cases. It started with younger people in their twenties and spread gradually to older ages as well. That increase in case number has translated into an increase in hospitalisations. As the hospitalisations have increased, as you look at the slide on the right here, you will see that very sadly but not unexpectedly, deaths are also increasing. So theres a simple message from this slide, which is that as the disease spreads, as it spreads across age groups, we expect to see increase in hospitalisations and unfortunately those increase in hospitalisations will lead to an increase in deaths. The virus has genetically moved a bit but it has not changed in terms of its propensity and its ability to cause disease and to cause death, even though of course most of the disease deaths occur in the older population. So where are we here? Next slide, please.

These are data from testing and Ill come back to that point in a minute and theyre data for England but the picture is fairly similar across the UK and, and Chris Whitty will say more about that. What we see from July, as we look at the increase in cases per 100,000 of population, an increase which has occurred over August and has increased into September. This is by different age groups and the top line, the blue line is amongst the 20 to 29-year-olds. But what you can see is there has been an increase in cases across all age groups. The lowest increase has been in children and in the population aged 70 to 79 but in every age group weve seen an increase. Could that increase be due to increased testing? The answer is no. We see an increase in positivity of the tests done, so we see the proportion of people testing positive has increased even if testing stays flat. And if we look at other sources of data such as, for example, the ONS study which takes a sample of people across the population and looks at it or studies like the REACT study we see a similar increase. In the ONS study, its now estimated that roughly 70,000 people in the UK have Covid infection and that about 6,000 people per day are getting the infection. So we are in a situation where numbers are clearly increasing. Theyre increasing across all age groups. Its a little bit different in different areas, in terms of geographies and Chris will speak to that and this increase in numbers is also translating into an increase in hospitalisation, which Chris will say more about. So theres no doubt we are in a situation where the numbers are increasing. What Id like to do is just remind you how quickly this can move. So the next slide is not a prediction, but it is a way of thinking about how quickly this can change.

So this is the UK reported cases per day against time and you can see running along the bottom there the number of cases over June, July and August. Up to roughly 3,000 cases per day or so in September, middle of September. At the moment, we think that the epidemic is doubling roughly every seven days. It could be a little bit longer, maybe a little shorter, but lets say roughly every seven days. If, and thats quite a big if, but if that continues unabated and this grows, doubling every seven days, then what you see of course, lets say that there were 5,000 today, it would be 10,000 next week, 20,000 the week after, 40,000 the week after. And you can see that by mid-October if that continued, you would end up with something like 50,000 cases in the middle of October per day. 50,000 cases per day would be expected to lead a month later, so the middle of November say, to 200 plus deaths per day. So this graph, which is not a prediction, is simply showing you how quickly this can move if the doubling time stays at seven days. And of course the challenge therefore is to make sure the doubling time does not stay at seven days. Therere already things in place which are expected to slow that. And to make sure that we do not enter into this exponential growth and end up with the problems that you would predict as a result of that. That requires speed, it requires action and it requires enough in order to be able to bring that down. One final word on this section. So as we see it, cases are increasing, hospitalisations are following. Deaths unfortunately will follow that, and there is the potential for this to move very fast. A word on immunity. Next slide, please.

When people have an infection, the vast majority of people get an antibody response, and we know that some of those antibodies are so-called neutralising antibodies. They do indeed protect against the virus. We also know that they fade over time, and there are cases of people becoming re-infected. So this is not an absolute protection, and it will potentially decrease over time. What we see is that something under eight per cent of the population have been infected as we measure the antibodies, so about eight per cent, so 3 million or so people, may have been infected and have antibodies. It means that the vast majority of us are not protected in any way and are susceptible to this disease. There may be other forms of protection that increase that number a little bit, other parts of the immune system, but it does mean the vast majority of the population remain susceptible, and therefore youd expect spread throughout them. The number of people with antibodies is a little higher in the cities, and it may be as high as 17 per cent or so in London. That may confer a little slowing of spread but not much more than that. At that point Ill pass over to Chris to take you through some of the other features of the epidemic. Chris.

Professor Chris Whitty, Chief Medical Officer for England:

Thanks, Patrick. Next slide, please.

What we have here are two maps, they are from England but there would be similar ones from Scotland, Wales and Northern Ireland. What we have on the left here is a map where the darker colours are the rate of transmission, and on the right what we have is a map where orange or yellow or brown represent an increasing rate of transmission. The darker that colour, the greater the rate of increase, and green or blue represent a stable or falling situation. And what you can see in, on the left side is that at the moment the very high rates of transmission in the UK are highly concentrated in particular areas, but there are significant rates of transmission in many parts of the UK with the darker colours. But what weve seen is a progression where, after the remarkable efforts which got the rates right down across the country, firstly we saw very small outbreaks, might be associated with a workplace or another environment. Then weve seen more localised outbreaks which have got larger over time, particularly in the cities, and now what were seeing is a rate of increase across the great majority of the country. Its growing at different rates but it is now increasing. And what weve found is that as the rate, as we go through in time, anywhere which was falling is now moving over to beginning to rise, and then the rate of rise continues in an upward direction. So this is not someone elses problem, this is all of our problem. Next slide, please.

This graph is a simple one, it simply shows the number of inpatient cases in England over the period from the first of August. And until that point in time, there had been a steady fall over a long period of time, right back from early April. And it then stabilised for a period and flattened out, but over the period since the first of September, you can see a steady, sustained rise in numbers with a doubling time, as with the cases, of probably seven or eight days. Now what that tells us is that if this carried on unabated, these numbers are relatively small, we are talking about around 200 at the moment, but if this, if this continued along the path that Patrick laid out, the number of deaths directly from Covid, Ill come back to indirect deaths, will continue to rise, potentially on an exponential curve. That means doubling and doubling and doubling again, and you can quickly move from really quite small numbers to really very large numbers because of that exponential process. So we have, in a bad sense, literally turned a corner, although only relatively recently. And we, I think everybody will realise that at this point the seasons are against us. Were now going into the seasons late autumn and winter which benefit respiratory viruses, and it is very likely they will benefit Covid as they do for example flu. So we should see this as a six-month problem that we have to deal with collectively. Its

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