Covid-19: Wales is past the peak. But now is not a time to be complacent

Picture a merger of @LloydCymru‘s coronavirus updates on Twitter, @AngharadHafod‘s graphs and US State Department visualisation of coronavirus.

Angharad Shaw

Anyone who follows a news story on social media will be familiar with the tendency to be pulled deeper and deeper into a story, and if you’re not careful, to be pulled to the extremes. We know this is dangerous, as it is at these edges where fake news finds its most fertile ground. We are all susceptible to it, whether we like it or not.

As someone with a background in statistical analysis (my PhD was in the area of Bioinformatics), the Covid-19 crisis has been of particular interest to me. Initially inspired by the work of the wonderful @LloydCymru, I realised that I should be contributing my knowledge and skills for the public good, too. And so, since 28th March, I have been contributing my graphs, and an interpretation of them based on my understanding of the statistics, to both toot.wales (@AngharadHafod@toot.wales) and Twitter (@AngharadHafod).

The data we have to work with are, as I am sure we all realise, not particularly reliable. There is little point in doing statistics with data on the number of cases, because we know that most people suspected to be infected with Covid-19 can’t get a test unless they are admitted to hospital. The only figure we have which is at all reliable is the number of deaths in hospitals, and even that figure comes with caveats – it is only hospital deaths, and it often lags behind (e.g. over Easter, we saw a number of deaths not being reported until Wednesday this week, making Wednesday appear particularly bad, when it was probably fairly average compared to other days over the Easter period).

Daily number of deaths in Wales

Putting my graphs, statistics and interpretations online has been an interesting experience. And I am very pleased to say that I have predicted a number of things about right. It’s around three weeks since I said the overall death toll in the UK from this wave would be around 20,000. That, at the time, sounded a lot. But if anything it will turn out to be a slight underestimate, though in the right ballpark.

I also have been predicting the peak to be over the Easter weekend, for some time. This is based on a couple of factors: the pattern taken by other countries (notably Italy, whose curve the UK as a whole has been following almost exactly, with a delay of 14 days), and the infection-to-death times that have been reported by researchers elsewhere (in the region of 18 to 23 days).

 

Peak

To see how this works, we need to understand the “reproduction rate” R of a virus. If R is greater than 1, then one person infects more than one other person, and the virus therefore spreads out of control until it runs out of people to infect. If it is less than 1, one person infects on average less than one other person, and the virus eventually disappears.

Total number of deaths since the first death in UK and Italy

Before lockdown, our R was greater than 1. We know that, because deaths were rising exponentially (doubling roughly every 3 days). After lockdown, I assumed that R would be less than 1. The fact that Italy saw its peak in deaths around 3 weeks after they locked down backed up this belief. And it appears to have been borne out by the reduction in the number of deaths – though slow – that we have seen since Easter.

Daily percentage increase in deaths in Wales

That statement needs to be immediately qualified, for those who have been watching the data: as referred to above, Wednesday’s figure of 60 deaths in Wales was almost certainly due to late reporting of deaths that occurred over the Easter holiday, and when averaged out with the four days gave a figure of 28: lower than each of the four days prior to that.

Dangerous

Covid-19 came to this house. At least, we assume it did. The doctor diagnosed it, via a phone consultation, with my housemate, earlier last week (the “classic” symptoms). Of course, we will never know for sure unless and until we get some sort of test. We suspected it was here 3 weeks ago. I’ve got away with it with relatively mild symptoms, and am now working on regaining my fitness – but otherwise well.

But the experience, for me, was many times worse because of worry. I had to take a break from Twitter. I skipped a couple of days of doing my analysis, not because I was too ill (though I wasn’t feeling great), but because I couldn’t face it. It was too easy to see all the bad news, and not to see the good news. Of course, as you would expect of a good Plaid Cymru member, I want to take every opportunity to criticise the governments in London and Cardiff.

But we have to do it right, with facts. There’s a mindset out there that doesn’t want to see the good news in the data, but wants to make it appear as bad as possible. That’s dangerous, not just for long term credibility, but for the here and now – the mental health of those with the disease, and those who fear it.

Positive

We are on the downward slope. The speed of the descent will depend on how good we are at maintaining our isolation and social distancing. Our long-term success will, as Adam Price said only yesterday (and I had said some time before – had he noticed?), depend on a strategy of testing, contact tracing, and isolation. The testing has to be in place before R gets above 1 (which it would do, if we simply lifted all restrictions), otherwise we will simply go into another cycle, the deaths will rise again, and we’ll face another lockdown.

Covid-19 total deaths in Wales

The economic cost (which one could be forgiven for thinking is all the Westminster Tory government cares about) of another lockdown would surely be greater than the cost of implementing a proper testing strategy. And of course, for the rest of us, most importantly, it would result in fewer deaths.

Look up, be positive. There is no room for complacency, but the worst is past. At least, it is, if our politicians handle this right from here on.

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Huw J DaviesKerry DaviesDr Dewi EvansClivemax wallis Recent comment authors
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max wallis
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max wallis

This is surely too simple. Assuming our profile is the same as Italy’s may coincide to a fist approximation, but can’t be right with their higher death rate, stricter lockdown, high density apartments etc. We expect that current spread of infection is hardly from living and exercising, because aerial transmission is zero for this virus. If 15 minutes close social contact (without touching) is needed to pass it on, going shopping won’t infect you, The main transmission is in hospitals and care-homes, workplaces, and household with one infected person, especially if they can pass it on pre-symptoms. Public transport transmission… Read more »

Clive
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Clive

Interesting article thanks. The UK part of the epidemic only makes any sense if 2 things are true. 1. The real infection rate is at least 10x or 20x of the 109,769 currently reported or I am missing something fundamental. 2. UK politicians have handed over real control to experts and are now just the publicity department. This is tactically a good thing. I have long held the view that politicians at any level should have zero influence on any part of health, education, social care, and policing other than finding the money to properly fund them. Like most people… Read more »

Huw J Davies
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Huw J Davies

I can’t help but notice that we’ve seen many politicians giving ‘in depth’ interviews about the Coronavirus strategy, most of whom are not from departments that have health care in their portfolio. I’m watching Michael Gove on the Andrew Marr Show. His departments have been Education, Treasury, Justice, Environment/Rural Affairs. I never knew being Chancellor of the Duchy of Lancaster for 2 months made him an authority on managing a pandemic virus! Yet these are the people we’ve trusted to run our country on our behalf. I’m afraid we are just getting what we deserve for our foolishness. You’d be… Read more »

Dr Dewi Evans
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Dr Dewi Evans

Diolch Angharad. Interpreting the mortality stats is quite difficult as the date of death of individuals is not reported. [Please forgive the rather clinical language]. The previous day’s figures include individuals who had died several days earlier. And assuming that time from contact to demise is reasonably similar one cannot identify trends without this information. Also figures relate to hospital deaths only in England. Figures are confusing in Wales re community deaths. Failure to test thoroughly adds to the difficulties of working out viral demographics. Surely a random testing of, say, 1,000 individuals across Wales would offer v useful data… Read more »

Kerry Davies
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Kerry Davies

If we have “peaked” we may be looking at a possible 4 week plateau before we start to see much reduction. At that point we will be exactly where we are now but on the other side of the bulge which took us six weeks to get up to. Yes I know it won’t work exactly like that, though if anything the “tail” could be almost never-ending. I suggest that we are looking at a lockdown until late May since the letter to the “shielded” from Dr Frank Atherton stipulated 12 weeks total isolation. That takes it to June 16th… Read more »

Huw J Davies
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Huw J Davies

I am considering using ‘Hawddamor’ but wonder how many people would reply ‘How the what?’.

I imagine SARS-CoV-2 as a pan of popcorn on the hob. You can take the lid off when the popping slows down but still need to watch out for the late ones that pop up and hit you in the face!