I wrote last week about how the number of cases of coronavirus were following a textbook exponential growth pattern. I didn’t look at the number of deaths from coronavirus at the time, as there were too few cases in the UK for a meaningful analysis. Sadly, that is no longer true, so I’m going to take a look at that today.
However, first, let’s have a little update on the number of cases. There is a glimmer of good news here, in that the number of cases has been rising more slowly than we might have predicted based on the figures I looked at last week. Here is the growth in cases with the predicted line based on last week’s numbers.
As you can see, cases in the last week have consistently been lower than predicted based on the trend up to last weekend. However, I’m afraid this is only a tiny glimmer of good news. It’s not clear whether this represents a real slowing in the number of cases or merely reflects the fact that not everyone showing symptoms is being tested any more. It may just be that fewer cases are being detected.
So what of the number of deaths? I’m afraid this does not look good. This is also showing a classic exponential growth pattern so far:
The last couple of days’ figures are below the fitted line, so there is a tiny shred of evidence that the rate may be slowing down here too, but I don’t think we can read too much into just 2 days’ figures. Hopefully it will become clearer over the coming days.
One thing which is noteworthy is that the rate of increase of deaths is faster than the rate of increase of total cases. While the number of cases is doubling, on average, every 2.8 days, the number of deaths is doubling, on average, every 1.9 days. Since it’s unlikely that the death rate from the disease is increasing over time, this does suggest that the number of cases is being recorded less completely as time goes by.
So what happens if the number of deaths continues growing at the current rate? I’m afraid it doesn’t look pretty:
(note that I’ve plotted this on a log scale).
At that rate of increase, we would reach 10,000 deaths by 1 April and 100,000 deaths by 7 April.
I really hope that the current restrictions being put in place take effect quickly so that the rate of increase slows down soon. If not, then this virus really is going to have horrific effects on the UK population (and of course on other countries, but I’ve only looked at UK figures here).
In the meantime, please keep away from other people as much as you can and keep washing those hands.
Have you looked at the Imperial College modelling paper from the team lead by Neil Ferguson? Sober reading
Yes, I’ve seen it. What really puzzles me about it is that their model seems to assume a doubling time of 5 days. I don’t understand why they’ve assumed that, given that the doubling time is about half of that.
Any idea of the top5 causes of death this year compared to last year? Ask only because some people say that the covid deaths have been manipulated. Wondering if the stats confirm this
Sorry, no, I haven’t looked at that. We should get those figures from the Office of National Statistics in due course, and I agree it will be interesting to look at. If we see a massive spike in deaths from “pneumonia”, then that might look like undiagnosed Covid-19 infection.
But I think it’s unfair to say that the deaths are being manipulated. It is genuinely difficult to count them, especially as so few people are being tested for the virus.
I’m puzzled as to why it’s gone quiet here in this most interesting of times for a stats guy? Must be some reason for this?
I’m puzzled why you think it’s gone quiet here. I’ve blogged twice in fairly quick succession after not blogging for 2 years.
Fair enough but your last long article was as above, and this is an unprecedented crisis with endless discussions about epidemiology and stats so I thought you’d be blogging a lot more? Perhaps weekly? I don’t know though, I’m not here constantly but I assumed you’d be full of ideas and opinions like every one else except you’d know what you were talking about unlike it seems everyone else these days!
No, I didn’t mean to imply you should do more blogs, just that the amount of work you put in to the last COVID blog was impressive, and now that we can all look back at your predictions and comments in light of the government mess ups, perhaps some comments on this would be helpful? After all you’re a medical statistician and never was there a time when such skills were more relevant!
Thanks for the vote of confidence, Ricky.
Yes, I suppose it probably is time for me to write something again. Will try to get to that in the next week or two. A lot has happened since i wrote the blogpost above.