Thread by @thomdvorak, Why lifting lockdown quickly is an absolutely moronic and counterproductive policy. (THREAD)I'm [...]

Why lifting lockdown quickly is an absolutely moronic and counterproductive policy. (THREAD)

I& #39;m not the first to post this but given the amount of senseless & foolish columns in The Telegraph, it needs to be repeated many times over. Lifting lockdowns quickly is idiotic.

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Why? Not because it won& #39;t achieve anything - it will make things even worse. Below is a simple SEIR model for COVID-19. It requires a number of assumptions (such as homogenous mixing) but where possible, I err on the side of being conservative.

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I assume unmitigated (absent any non-pharma interventions) R0 is 3.
It’s what we’ve seen so many times over the last few months – the spread is exponential. Starts slow, builds up. We’ve managed to halt this with social distancing, bringing R below 1 but only at the cost

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of putting the country in lockdown. Once you start lifting restrictions, number of cases will increase again.
This is an inevitable feature of people mixing – once you lift some containment measures and people interact, the transmission rate will go up and R will go up.

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Now, you may have heard all these talking heads saying “we’re killing the economy” and that is why we must end the lockdown. Right. Below is the chart with the Google Mobility data. You will have noticed that people started to limit movement *before* the actual lockdown

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was imposed (dotted lines above are 7-day moving averages). Again, not surprising – a lot of people are scared of the disease (and rightly so). They will take up social distancing voluntarily so long as the virus remains a threat.

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Now let’s put these two insights together. If you abruptly and prematurely lift the lockdown measures, transmissions will go up. It takes little at the start to have a massive second peak – and a lot of people know that by know. So what will happen?

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Well, cases will go up and some people will choose to remain in isolation. But others won’t (you’ve seen what was happening on VE day despite no change in govt policy). Transmission rate will go up. Cases will go up. Deaths will go up.

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At the same time, the economy will not be revived because lots of people will stay at home instead of going to restaurants. But given the exponential spread of the disease, sooner or later (sooner) the NHS capacity will become strained again (*illustrative* SEIR model below)

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Another lockdown will have to be imposed.

So we have the *worst* of both worlds. A second peak in infections, many more deaths AND a locked-down economy at standstill. Not to mention that given the external weakness, the economy is already between a rock & a hard place.

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The issue for the economy is not the lockdown. It is the virus. The virus is what changes people’s behaviour. But don’t take it from me, take it from the data.

https://twitter.com/JWaldfogel/status/1258741445235822592

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https://twitter.com/JWaldfogel/status/1258741445235822592

So are lockdowns useless when people stay at home voluntarily? No. A good thread from @BachmannRudi points out some reasons why lockdowns are important. I would add that a part of population will not distance voluntarily. You have to mandate it.
https://twitter.com/BachmannRudi/status/1258863972570234884

12/">https://twitter.com/BachmannR...

https://twitter.com/BachmannRudi/status/1258863972570234884

It’s the same reason why not “trust the British public & their common sense”. Because it only takes a small fraction of morons to make things really bad. But more than that, it’s the virus’ asymptomatic spread – very succinctly noted by @t0nyyates
https://twitter.com/t0nyyates/status/1259236973241384961

13/">https://twitter.com/t0nyyates...

https://twitter.com/t0nyyates/status/1259236973241384961

Note that in the Google Mobility chart, the voluntary drop in movement probably wasn’t enough to bring R below 1. So again, we’d end up with the worst-of-the-both worlds compromise with part of population responsibly & voluntarily socially distancing

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(enough to hurt the services sector by staying at home + as precautionary savings go up, durable purchases will be postponed) while the virus still spread exponentially thanks to those still going about their business.

Meanwhile, where are we now?

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As Johnson prepares to lift some restrictions today & change the slogan to an ambiguous sequence of words, he might again talk of the “apparent success” in how we’re dealing with the outbreak. About that. (visualiser by @JoMicheII http://macroflow.org/corona/ )

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That is why the lockdown must be lifted gradually, carefully monitoring the increases in the spread of the disease and, if necessary, backtrack on some of the easing. We must be vigilant, we must be careful, and we must be patient. We have the shield the economy as best

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as we can and help those who can’t go to work. Some restrictions are likely to be with us for a long time. We’ll have to make some unpleasant changes to our daily lives.

But it’s the virus that is wrecking the economy, not the lockdown.

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