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How much difference would an earlier shutdown have made?

May 21, 2020 - 12:12pm

The Telegraph reports that if Britain had locked down one week earlier, 75% of British Covid-19 deaths would have been prevented. It’s attracted the attention of the BBC’s Jeremy Vine, and George Monbiot in The Guardian.

It’s based on a model by James Annan, a climate scientist, published on his blog, which was mentioned briefly by the BBC’s always fantastic More or Less programme on Tuesday.

I’m not here to debunk the model, exactly, and I would never dare contradict the More or Less team. I just wanted to flag a reason to be concerned with it.

The word ‘model’ can describe many things, from an all-singing, all-dancing climate model which simulates the action of the entire atmosphere and ocean system down to cubic-kilometre units, to a simple statistical curve which says ‘if X goes up by 1, Y will go up by 2’. The Annan model is very much at the latter end.

Hindcast/forecast for daily deaths in the UK. Credit: James Annan

Its model is amazingly simple: Covid-19 infections were doubling about every 3.5 days in March; that means you get two doublings in a week. So, if lockdown had happened a week earlier, it would have prevented two doublings, so you’d have got a quarter as many infections and therefore a quarter as many deaths.

You barely even need to call it a model: it’s a back-of-the-envelope calculation.

That doesn’t make it wrong. Simple models are not bad; sometimes they’re more appropriate. But simple models are simple. There’s lots they don’t take into account.

Most noticeably, this one assumed that if lockdown had happened a week earlier, everything else would have happened a week earlier too. But we know that by the time lockdown happened, British lives were already very different. People were voluntarily behaving very differently even without government orders. Schools had closed a week earlier, but I know people who’d taken their kids out of school even before then. I was avoiding public transport, as were millions of others; many businesses were already working from home.

The peak of deaths came on 8 April. That’s barely two weeks after lockdown — surprisingly fast, given that the mean time from infection to death is 20 days, although the median time is shorter. Lockdown may well have been what made infections actually start to decline, but a statistician I spoke to says it seems very likely that voluntary changes in behaviour had at least some effect on flattening the curve.

So it’s not as simple as lockdown a week earlier –> two fewer doublings –> 75% reduction in deaths. If we’d moved the entire process forward by a week — school closures, behaviour changes, everything — that might have done it; but a lot of behaviour change was driven by seeing what was happening elsewhere. Britons saw Italy and China and became rightly scared. It’s not easy to see how we’d have brought that forward.

In their report, More or Less addressed another point, which is that the model also assumes that an earlier lockdown would have been as fully complied with as the one that actually happened; a big assumption, given that a week earlier, people might not have been so scared. That caveat hasn’t made it into any of the other coverage.

None of this is to say that an earlier lockdown would not have saved lives. It almost certainly would. But the stark claim that it would have prevented 75% of deaths — 30,000, so far — is wildly overconfident and I think should be reported with far more uncertainty; the true figure could be much lower.


Tom Chivers is a science writer. His second book, How to Read Numbers, is out now.

TomChivers

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olivps
olivps
3 years ago

You can’t save lives without a cure. On the best you can say that by chance they wouldn’t had yet contact. Even so, assuming that places very remote like that nursing home in the Isle of Syke couldn’t be free of infection my believe is that it wouldn’t matter anything the timing of the lockdown in terms of overall deaths. Time will tell us but so far all the date points out that the disease was already past the peak in almost all European countries when lockdown measures were instituted.

Paul Wright
Paul Wright
3 years ago
Reply to  olivps

You can’t save lives without a cure. On the best you can say that by chance they wouldn’t had yet contact.

This is not true: “flattening the curve” reduces or even removes the overshoot you’d get for an unrestricted virus. Check out the Scenario 0 vs Scenario 1 in this playable simulation.

Nick Whitehouse
Nick Whitehouse
3 years ago

Personally I think we should blame the press, millions of Professors and the Labour Party for not calling for Lockdown in December, or even November.
My “model” shows that not only would we have no deaths – in fact there would have been a negative number of deaths.
After all, we have had the examples of earlier virus outbreaks, which did not affect us. So it was obvious in November that this one would be different.

So as Tom implies, this model is rubbish – with some hindsight thrown in.

Stephen Follows
Stephen Follows
3 years ago

If we’d had lockdown from the 1940s onwards, many of the people who are now dying might not have been born. That would really have reduced the death toll.

Basil Chamberlain
Basil Chamberlain
3 years ago

I don’t think people were really ready to be locked down any earlier. On Monday 9th March, I was at the Royal Opera House for Fidelio as part of an absolutely full house; most people were still joking about the virus. The next night I was at the cinema (watching a rarely screened classic) and the general sense was that everyone had been worried that the screening would be cancelled because of the virus. By Friday, I was beginning to hear people complaining that it was irresponsible to attend public events. Out of curiosity I glanced back at the ROH website for the next performance of Fidelio; more than a hundred seats had been put up for resale. During those five days, people’s attitudes and behaviour began to shift dramatically. As the article suggests, there’s a sense in which the formal lockdown was a response to that shift as much as a cause of it.

Stephen Follows
Stephen Follows
3 years ago

Quite so. Plenty of people have complained about the Cheltenham Festival and Liverpool’s match against Atletico Madrid both going ahead, but similarly at that point, no-one was taking the thing seriously, and there would almost certainly have been near-riots in both places if large numbers of fans had been turned away.

On a more exalted level, I was at an LSO concert at the Barbican on Thursday 12 March, where the conductor and the soloist bumped elbows at the end of the concerto and then fell about laughing on stage, as did the audience in the stalls, before all repairing to the bar. (I guess that may be the last concert the LSO will ever give, mind you, because the social distancing will make all future concerts unviable.)

John Munro
John Munro
3 years ago

Do the English now riot so easily? As a people are they that irresponsible? As for concerts. Start going to Chamber Music concerts or solo performances.

lawrence.john
lawrence.john
3 years ago

Then you watch the Sunetra Gupta video and realise that it would have made no difference if the lockdown happened earlier, later or not at all…

david bewick
david bewick
3 years ago

Lots of stuff going around and epidemiologists (see Graham Bradley) suggest the time to lockdown to prevent deaths was January but the time to lockdown for max effect without testing the population’s willingness to comply(lockdown fatigue) and to prevent the negative effects of lockdown is as close to the peak as you can reasonably calculate. There is also opinion that the lockdown was unnecessary and that the virus was already here in February and the damage was done then. I keep hearing New Zealand but they were actually late locking down. They didn’t lockdown until 28th March. Taken in the round the latest country to lockdown in Europe was Germany on 22nd March prior to which they has no controls in place. For every opinion that the lockdown was late there’s another that says it was too early or not required at all. The govt were spooked (again!) by Neil Ferguson’s prophecy of disaster. He did the same for previous govt’s over foot and mouth, bird flu, swine flu, mad cow disease…..

Dougie Undersub
Dougie Undersub
3 years ago

Sigh … We’ve gone from the situation where anyone could search the internet to find an epidemiologist whose views fitted their own to, now, everyone can have their own model to believe in.

Adrian Smith
Adrian Smith
3 years ago

All models are wrong – some models are useful.

The problem with all Covid models is you can only validate them after it is too late to act on them. That is where the precautionary principle comes in as exploited by climate change fanatics. The best thing about them is if they change behaviour and it does not have the effect you can claim you dd not change enough, if the effect you hope to achieve happens you can claim you were right. Given some of the better data we now have from around the world, especially policy outliers like Sweden it might be getting close to being possible to update the more sophisticated models to come up with something that is a bit more valid.

Alan Hall
Alan Hall
3 years ago

A climate “scientist”(actually modeller), with a rubbish analysis supported by BBC and Guardian, who would have thought! Annan should be ashamed of himself. We can all do our own analysis. Figures on the OWID show that there is not much correlation between date of lockdown and overall deaths.

For example, a comparison between Belgium (now 792 deaths/million), Germany (98 deaths/m and UK (531 deaths/m) is as follows:
Belgium lockdown 18th March when they had 107 cases/million and 5 deaths (0.42/million).
Germany lockdown 23rd March with 296 cases/m and 94 deaths (1.12/m).
UK lockdown same as Germany with fewer cases 84/m and higher deaths at 285 (4.2 /m).
There is nothing to learn from this regarding date of lockdown. The lack of preparation and poor performance by the NHS, PHE, Universities etc most likely the basis for and cause of UK handling of the crisis, followed by Government following so called scientists. BUT it is still too early to say unless one has an agenda.

david bewick
david bewick
3 years ago

The Guardian has this to say on 6th March…..
However serious a threat coronavirus poses, it’s important to retain perspective. More people die of tuberculosis each day ““ and of air pollution every five hours ““ than have succumbed in two months of Covid-19.

If that game of morbid calculus is not exactly reassuring then try this: the vast majority of people who have had the illness have recovered. Children seem to be largely untouched. A vaccine is in the (admittedly fairly long) pipeline. We know where the illness came from, and the situation in that country is improving. The vast majority of cases are asymptomatic. You can kill it with antiseptic spray; science is all over it; clinical trials are under way.

This is not to minimise what has happened, or predict what will. It is merely to keep a sense of proportion about coronavirus. There is no point succumbing to a fear pandemic before a disease pandemic has even taken hold. And besides, there have been a number of silver linings. Experts are back. Emissions are down. Personal hygiene has had a much needed overhaul “¦

This is the full article…https://http://www.theguardian.com/world/2...

Jordan Flower
Jordan Flower
3 years ago

If Hitler’s mother had aborted him, then no third reich. smh @ mrs. hitler.

Colin Sandford
Colin Sandford
3 years ago

Hind sight is a wonderful thing. There are so many ‘what ifs and why didn’t they do that’, no one knows for sure what the outcome would have been.
The bottom line is we as a nation have very poor health and it takes very little to kill us off and the result would probably be much the same.

Martin Goldthorpe
Martin Goldthorpe
3 years ago
Reply to  Colin Sandford

I remember the debates in early March before the lockdown. There was a lot of discussion about protecting only the elderly, given the death rates in China and Italy.(I recall David Blunkett on R2 Jeremy Vine arguing against it.)
If you look at the ONS stats for April 2020:
97% of Covid-19 deaths occurred in over 64s,
94% of Covid-19 deaths occurred in over 69s,
91% of Covid-19 deaths occurred in over 74s.
So in hindsight protecting the elderly and letting the rest of us quickly develop herd immunity whilst getting on with our lives would have been the thing to do.
There again, Table 1 of the infamous Neil Ferguson report, showing the strongly age-related Infection Fatality Ratios from Chinese deaths, told us that.

p web
p web
3 years ago

Already only 1 in 10 parisians were wearing a mask yesterday. Nice sunshine so why spoil it by wearing a mask. The same people were storming the bastille demanding their masks a mere few weeks ago. How quickly people forget. It doesnt bode well for the second wave. And the travel industry trying to open back up- but none of the airlines have really put in place really strict policys. Its going to happen again and who knows how the politicians will reacte

Patrick Cosgrove
Patrick Cosgrove
3 years ago

“.. a big assumption, given that a week earlier, people might not have been so scared.”

Fair point, but if your question was rephrased to ‘How much difference would can earlier shutdown have made if Boris Johnson has listened to the warning, and taken it seriously?”. the simple model would probably have applied because people would have been scared.

I also suggest that Unherd stops banging on about comparisons with Sweden and gets some interviewees from Australia and New Zealand where they did lock down earlier and harder, and – touch wood – appear to be reaping the benefits.

Julian Fletcher
Julian Fletcher
3 years ago

Although differences in reaction to the virus involves a multi-factorial analysis, around population mix, densities, level of incomes, ethnicity and even things like Vitamin D production as the southern hemisphere had just gone through its summer etc before you make comparisons between countries.

Australia and New Zealand did lock down early (not sure they were harder than the UK or any other European country) but the timing of it is not the only reason for different outcomes.

olivps
olivps
3 years ago

You definitely can compare two far away countries endpoints with a young population and different urban landscape with any of the main inter-connected European countries. Lockdown would only changed the outcome if you had either a cure, a vacine or the assurance that the virus would vanish from Earth, things that anyone who knows a little of viral diseases know are almost unrealistic assumptions (at least by now)

Paul Goodman
Paul Goodman
3 years ago

There is a view that unless a vaccine can be developed (none has yet for the many corona-viruses) that Australia and NZ have it yet to come unless they remain isolated for ever. The truth seems to be that Sweedens lighter social distancing approach has lead to less economic pain but similar deaths rates to those who have been characterised as having locked down too late. Just seems a more robust analysis; no appearances or touching wood.

Pollution is the new focus now though which is fascinating.

Deus Abscondis
Deus Abscondis
3 years ago

So called “lockdowns” actually work – pure cause and effect. The basis of infection transmission isn’t new to science and medicine. The reason why the anti-lockdowners don’t mention Australia and New Zealand is because they are successful. Of course massive testing and tracing is important – another thing the do nothing anti-lockdown mob object to. They are a rather dumb mob and really have no idea of how to control a contagious disease and don’t offer any realistic alternatives. More death, suffering and economic damage seems to be inconsequential – they seem to think they have a right, liberty and freedom to spread a notifiable contagious disease, they don’t.