Friday, 26 February 2021

The lockdown debate with Toby Young

I had an hour long debate about lockdown policy with Toby Young on TalkRadio yesterday. You can watch the whole thing below. Apologies for the sound quality a times. Skype didn't seem to work as well Zoom for me in this.

Much of what was discussed has appeared in more detail on this blog before - and also on the Quillette article that started all of this. I expected a disproportionate number of smileys in the online audience so I started off with the basics. SARS-CoV-2 is a virus that spreads from human to human. If humans don't interact with others, it can't spread. The claim that lockdowns don't reduce the number of infections therefore requires extraordinary evidence.

Florida has recently joined Sweden as the place that has supposedly proved that lockdowns don't work. Neither has had a lockdown in the last six months and although they've had a lot of COVID-19 deaths, they haven't had an exceptionally high number. 

There are more restrictions in both Sweden and Florida than the smileys acknowledge. Even if there weren't, it obviously wouldn't prove that lockdowns don't work. At best, it would show that some places can keep cases down to a manageable number level (debatable in the case of Sweden) without resorting to lockdown. 

Good for them. I've always wished Sweden well. If Britain could have kept the virus at a manageable level through voluntary measures, I would have never supported lockdown. The problem is that we could not and manifestly did not. We had reached an NHS-busting level of infections by the end of December - higher than the peaks in both Sweden and Florida pro rata - and suffered the consequences in January. We couldn't sustain those kind of levels, let alone allow them to rise.

It would have been a suicidal gamble for the government to do nothing and simply hope that people would radically change their behaviour of their own accord or that the virus would somehow go away at the start of January. 

I mentioned the Google Mobility data in the debate. I find it fascinating. In Sweden, you can almost see the exact moment at which people's behaviour changed in late December, thereby leading to the decline in cases in January. You can also see the subsequent rise in movement which correlates with the current increase in cases.


This is evidence that people can change their behaviour voluntarily (albeit with a lot of nudging and a few regulations) in a way that brings case numbers down. But there are two things I find particularly interesting about this data.

Firstly, mobility fell to a record low in Sweden in late December. Even the current level is lower than it was last spring when rates were falling. In other words, the kind of behavioural change that was sufficient to bring case numbers down in the spring no longer seems to be enough, presumably because winter makes it less congenial to meet outdoors.

Secondly, look at the graph below, particularly November and December.

In the UK, mobility was more than 30 per cent below normal levels in December and yet rates of infection were rising rapidly. In Sweden, they fell to that level in late December, but that was sufficient to bring rates down. 

This is just one measure of mobility, but all the others show a similar trend and a similar disparity between the two countries. It strongly suggests that even if the British had been able to reduce their mobility to Swedish levels voluntarily, it wouldn't have been enough to stop the rise in infections. This might be because of the B117 virus which is dominant in Britain or it might be something else. It could be any number of things. It is a reminder than Sweden and the UK are different countries. You cannot assume that what happens in one place will happen in another.

As I said in the debate, we tried a more 'Swedish' approach in December and unfortunately it didn't end well.

Wednesday, 24 February 2021

Zero tolerance for Zero Covid

Years ago I debated Gabriel Scally on the issue of plain packaging. He was wrong then and he's wrong now. He thinks the UK should pursue 'Zero Covid'. I explain why I disagree in this New Statesman article.

There is a belief among some people that the first lockdown could have achieved total suppression of the virus if it had only been kept in place a little longer. This is delusional. Lockdowns do not have a universal definition, but mine is the period between pubs being closed and pubs being open (along with the rest of the hospitality industry and it no longer being illegal to meet friends and family indoors). By this measure, the first lockdown in England lasted three and a half agonising months. Throughout this period, the case rate fell, but with diminishing returns. We never really got below 500 positive tests a day (and you can double that number because half the infections were not reported). The lowest number of total infections in England estimated by the Office for National Statistics was 14,000 on 9 July. 

We tried a lengthy lockdown, and we never came close to defeating the virus. Case numbers were roughly halving every four weeks. It takes a long time to get from a thousand to zero at that rate. A massive, Wuhan-style effort could have sped it up but there are a lot of people who cannot work from home and a lot more who are prepared to break the rules when they last for too long. We don’t have the geographical advantages of New Zealand or the ruthlessness of the Chinese Communist Party. We can’t even stop people entering the country on dinghies. 

Perhaps in June 2020, Boris Johnson could have persuaded a weary public to accept another few months of lockdown, along with even tougher restrictions. I somehow doubt it, but it doesn’t matter. We are not in that situation now. 


Tuesday, 23 February 2021

Nicotine pouches

The Observer has noticed nicotine pouches and it isn't happy.

Flashing an ice-white smile for her 50,000 followers on TikTok, a fresh-faced young woman pops a flavoured nicotine pouch into her mouth, as one of Pakistan’s most popular love songs plays in the background.

More than 3,000 miles away, in Sweden, another social media starlet lip-syncs for the camera, to a different pop tune. The same little pouches, made by British American Tobacco, appear in shot.

Critics say that such viral videos, even if they aren’t paid-for adverts, are the consequence of a global marketing push designed to offset dwindling cigarette consumption by recruiting the nicotine consumers of the future.

By that standard, I guess any social media post that shows a product counts. I don't know what the law is in Pakistan, but you can advertise snus in Sweden so I'm sure you can advertise a tobacco-free equivalent.

BAT makes much of how such products are helping adult smokers switch to less harmful alternatives, under the slogan “A Better Tomorrow”.

By 2023, the company expects to be targeting 500 million nicotine consumers with £100bn a year to spend. Products other than cigarettes are driving much of that growth.


Financial results released last week showed an annual pre-tax profit of £8.7bn as “non-combustible” products began contributing to earnings for the first time. The number of customers using them jumped by 3 million to 13.5 million, as the pandemic sparked a migration from cigarettes to more lung-friendly nicotine-delivery methods.


Happy days. It's a win-win for business, consumers and 'public health'. 

But not in Observer world...

However, such products are far from risk-free and the trend for promoting them via social media and popular influencers is causing concern.

Not just not risk-free, but far from risk-free! So what, exactly, are the risks? Alas, the lengthy article never gets round to saying. Nor does it get round to naming the 'critics' who are 'concerned' about this, except someone from an organisation called Corporate Accountability which seems to be against big businesses in general.
The Observer article is based on an article from the 'Bureau of Investigative Journalism', the organisation that famously got Newsnight in a lot of trouble over Lord McAlpine and which is now funded by Mike Bloomberg to write anti-vaping pieces and be generally negative about tobacco harm reduction. It finds a critic from within 'public health', but it's just the corpulent know-nothing Martin McKee whose opinion is worthless.

The gist of it is that BAT markets its nicotine pouches and people under the age of 18 might try to buy them.

Lyft has no tobacco in it but does contain nicotine, making it an over-18s product. Yet multiple TikTok videos feature Swedes who appear to be of school age using them.
Do they, aye?

In Spain, a campaign for BAT’s heated tobacco product Glo has been fronted by boy band Dvicio, via Instagram and a series of concerts. The “boys” are all in their late 20s or early 30s, but were last year’s summer cover stars for tween magazine Like
This is lame stuff and BAT have responded with some fairly obvious points.

"Our social media accounts are age-gated so they are only visible to those users who have confirmed that they are 18+ (or other applicable minimum age),” it said.

The company added it was essential it marketed “reduced-risk” products so smokers were aware of them.

To be clear, these are good products. If anything, they should be advertised more. Everyone knows what cigarettes are but I bet most smokers are unaware of nicotine pouches. They are not 'far from risk-free'. They are as risk-free as nicotine patches, the only 'risk' being a caffeine-level increase in heart rate, as far as I can tell. They can't be sold to children and if adults want to buy them, that is up to them. End of story.

Monday, 22 February 2021

Exiting lockdown at a snail's pace

The government promised that its strategy for exiting lockdown would be based on data not dates. Instead, it has produced a rigid and anally-retentive plan focused on arbitrary dates which acts as if we haven't learned anything from previous lockdowns and assumes that we don't know anything about the vaccines coursing through 18 million people's veins.

We're going to look ridiculous when we've vaccinated all the priority groups before the rest of Europe and are still hanging out in parks while the rest of Europe has reopened. I fear the quack modellers at Imperial and Warwick have had too much influence again.

I've written about this for the Telegraph.

Anyone minded to look at the data can see that both the current lockdown and the vaccination programme have exceeded expectations. Despite experts warning that the ‘UK variant’ would make it impossible for R to fall much below 1, the number of new infections has fallen by 80 per cent since the start of January. 

Eighteen million people - a quarter of the adult population - have had their first jab of a vaccine that is working better than anyone could have hoped. Research from Israel not only shows that two doses of the Pfizer vaccine is 95.8% effective in preventing hospitalisations, but that even a single dose reduces the risk of symptomatic infection by 85%. The Oxford/AstraZeneca is also exceeding expectations, with a study suggesting that a single dose is 76% effective in preventing symptomatic disease and 100% effective in preventing hospitalisation. Recent research from Scotland found that a single dose reduced the risk of hospitalisation by 94%. 

With 95 per cent of the over-70s having received at least one jab, there can be no justification for making the nation wait until May to get a haircut. The timeline put forward by the Prime Minister would be excessive even if we didn’t have vaccines. In the first lockdown, almost everything was open after three and a half months. This time around, despite the 32 million people in the priority groups on course to have at least one dose of a vaccine by April, there are doubts about whether we’ll be able to go to the pub or have a holiday in the UK by May. 


Friday, 19 February 2021

A debate with Terence Kealey about intellectual property

I recently took part in an IEA head-to-head debate with Terence Kealey about intellectual property. I am broadly in favour, he is broadly against. Check it out.

Tuesday, 16 February 2021

Anti-alcohol academic wants pub booze ban

Last May, the Scottish government gave £500,000 of taxpayers money to Niamh Fitzgerald to do some research into how pubs could safely reopen. Fitzgerald is no stranger to taxpayers money. In October, she was given £1.1 million by the National Institute for Health Research to study the effects of pub opening hours on ambulance call outs. She has also had money from the Scottish government to study minimum pricing.

If you're familiar with the SNP's attitude towards alcohol, you won't be surprised to hear that she is a keen advocate of minimum pricing and not too keen on the sale of booze. She is the director of the Institute for Social Marketing, the old stomping ground of the fanatic Gerard Hastings, and is deputy director of SPECTRUM, which was set up in 2019 as a research institute but which rapidly became yet another state-funded lobby group. 
The fruits of Fitzgerald's labour were published today, conveniently overshadowing the news that alcohol consumption fell in Scotland during lockdown
Pubs might need curfews and alcohol bans to stop Covid spreading, experts warn
Pubs might not be able to prevent Covid from spreading without curfews or alcohol bans, warn scientists.

A team of Scottish researchers examined Covid-19 measures in licensed premises last summer and found some worrying "pinch points" which could see the infection spread.

They say blanket closures, curfews or alcohol sale bans could be more likely to be deemed necessary to control the spread.

Who could have guessed that a neo-temperance campaigner who come to such a conclusion? Scotland has already experimented with alcohol-free pubs during the pandemic. It didn't work well for the pubs or their customers, but the 'public health' lobby rather liked it. The fact that pubs cannot survive without selling alcohol is of no concern to academics.
The study used to justify this preordained conclusion involved interviews with some people from the hospitality industry and a spying mission in 29 premises when the pubs reopened in the summer. The researchers found a number of transgressions which they list sombrely, including 'customer mixing and overcrowding in toilet areas' and 'a brief bit of singing' during a football match. 
They conclude:

Despite efforts on the part of premises, and detailed guidance from government, potentially significant risks of COVID-19 transmission persisted in a substantial minority of observed bars, especially when customers were intoxicated. Blanket closures, curfews, or alcohol sales bans are more likely to be deemed necessary if such risks cannot be acceptably, quickly, and cost-effectively reduced through support and sanctions for premises operators.

Normally we rely on bodies like Trading Standards to see how well regulations are being adhered to. One benefit of using nationwide data from such organisations is that we get a more accurate picture than if we rely on anti-alcohol academics having a mooch around a handful of boozers. 
Of course, rules and guidelines will sometimes be breached, as they are everywhere from time to time. It is almost impossible to remain two metres apart from everyone in a supermarket, for example, but nobody is suggesting they be banned from selling food.
The fact remains that there is very little evidence that hospitality venues are a major source of infection. If they were, you would expect those who work in pubs to be at high risk of infection and yet, as the Scottish Licensed Trade Association points out...

One widely reported survey, by industry group UKHospitality, spanned 12,522 hospitality venues across the UK that employ a total of 358,000 people. It found that in the 14 weeks since July 4, 1,728 staff members had been infected with Covid, equating to an employee infection rate of 0.48% across 20 million work shifts across the UK.

According to this survey, the customer infection rate was found to be even lower – with just 780 customers infected with the virus over the 14-week period, which equates to a 0.06% customer infection rate per venue.

If, as the study concludes, transgressions were only found in a minority of pubs, the solution is to police the regulations properly. Banning pubs from selling alcohol would throw the baby out with the bathwater, but that's fine with the Institute for Social Marketing and SPECTRUM because they don't like the baby and are not particularly keen on the bathwater. 

Since the start of the pandemic, I have been documenting the actions of the corona-vultures of 'public health'. These are the people who are supposedly experts in public health and yet have nothing to contribute when a genuine public health appears. Instead, they use the crisis to advance their existing agenda and even criticise those who are trying to help.

This seems to me a classic example. It is also a classic example of the endemic sock-puppetry of the Scottish state wherein the SNP dishes out money to activist-academics who share its agenda. 

The emergence of a vaccine for COVID-19 has got the corona-vultures worried. They fear they only have a few more months of using the pandemic as an excuse for their petty authoritarianism. But that will be long enough for them to try out their most drastic experiments. In the short term, they can go wild. In the long term, their aim is to keep as much emergency regulation on the books as possible when the emergency is over.

Friday, 12 February 2021

The COVID modellers have jumped the shark

Academics from Warwick have modelled the effects of vaccinating the population and removing 'non-pharmaceutical interventions' in England over the next eighteen months. The study was produced, I think, on 13 January. The findings are certainly eye-catching.

In their best case scenario, lockdown reduces R to 0.8 and 3 million vaccines are delivered each week from February (with 1 million a week delivered in January). Lockdown ends on 22 February and all NPIs are dropped by July. 
This means that everybody who wants a vaccine has had one (or, indeed, two) by the summer. The authors nevertheless predict that England will see 2,000 deaths per day in August. If the vaccines don't work as well as expected, this rises to nearly 5,000 per day.

I am only an interested amateur and am happy to be put straight, but WTF?!? Last August, when there was no vaccine and minimal NPIs, England had about eight deaths a day. At the height of the winter second wave, it had 1,238 deaths (January 19th). 
5,000 deaths per day is more than 70 per million. Even the worst hit countries such as Belgium and Czechia never got above 30 per million at the height of their epidemics. And yet these guys think that it could far exceed than that in Britain in the summer after the vaccines have been fully rolled out. Even in their best case scenario, there would still be 1,000 deaths a day.

When your model gives you such an implausible result, you have to question your assumptions. So what are they?

According to the brief text, the authors expect all these deaths to come about because some people will refuse to take the vaccine and some people who take the vaccine won't be protected. 

Uptake: Throughout we assume 95% uptake in care homes, 85% in the general population above 50 and 75% in adults below 50 for the first dose. This drops to 75% for the over 50s and 66% for the under 50s for the second dose.

People aged under 50 are almost irrelevant in terms of Covid mortality so the figure to focus on is 85%. 
Here are their assumptions about protection against symptomatic disease...

Efficacy: We sub-divide into the effects of protection against symptoms (disease efficacy) and reduction in transmission – we assume that transmission blocking acts by stopping infection. Disease efficacy is taken as 70% and 88% after dose 1 rising to 88% and 94% after dose 2 for the Oxford and Pfizer vaccine respectively. Transmission efficacy is taken to be 48% rising to 60% for both. Protection is lagged by 14 days after the dose is delivered.

This roughly reflects what the trials have shown us about these vaccines.

The authors don't provide a figure for the total number of deaths in their projected third wave, but it looks around twice as bad as the second wave which has killed about 60,000 people in England and will probably end up killing around 75,000. So, as a very rough estimate, they're suggesting there will be 150,000 deaths after everybody who wants a vaccine has had one. That's more than all the deaths we've had already. Unsurprisingly, the authors call for the government to hold back on relaxing lockdown, although quite what this would achieve is unclear: the lesson of the study is that COVID-19 will get us all eventually.

Imperial have also done some modelling. This study was produced on 14 January, the day after Warwick's. It makes exactly the same assumptions about transmission efficacy and disease efficacy. Unlike Warwick, they assume vaccine uptake is 85% across all age groups. They assume that NPIs are gradually lifted on the first day of each month but do not say which ones. As with Warwick, all NPIs are lifted by 1 July.

The assumptions are therefore very similar and the conclusions are only slightly less gloomy. Like Warwick, they predict a massive summer wave and 130,800 dead even under their most optimistic scenario.

Again, the authors encourage the government to be extremely cautious in relaxing the lockdown.

In both cases, they are predicting a dramatic rise in cases followed by a steep fall. The Warwick model shows a classic epidemiological bell curve. Both models imply that everyone who can get infected will get infected and that the death toll will only be ameliorated by the vaccines providing a measure of protection against symptomatic disease. The lack of a resurgence in winter 2021/22 suggests that the epidemic will have run its course after this final, devastating wave leaves no one left to infect.

If the assumption is that nearly everyone gets infected, the 15% of the population who are not vaccinated will die at the normal rate of about 1 in 100. A smaller proportion of the 85% who are vaccinated will die. That's still a lot of deaths. 

But there are two big problems.

Firstly, both models underestimate how many people will take the vaccine. So far, 91% of the 80+ cohort have taken it and 96% of those aged 75-79 have taken it. That's a lot more than 85% assumed in these models.

Secondly, and more importantly, the estimates of disease efficacy (the reduction in risk of getting symptomatic disease) are roughy correct, but the authors seem to have overlooked the crucial point about the AstraZeneca vaccine which is that there were 'no severe cases and no hospitalisations' in the trials. The vaccine seems to be 100% effective in preventing death from COVID-19. The Pfizer vaccine is 95% effective in preventing symptomatic disease altogether, so the number of deaths that would occur among the cohort who take it would, presumably, be very low (in Israel, there were 4 severe cases and no deaths among 523,000 vaccinated people).

It is incredible that neither study factors in the effect of the vaccines on severe disease and mortality. You can forgive them for not predicting that so many people would take up the vaccines, but we've known about the AZ vaccine's ability to prevent severe disease and death since November.

Their results seem to be based entirely on transmission and the prevalence of symptomatic disease. The mortality figures they come up with are so enormous, I can only assume they jumped to the conclusion that the fatality rate would be the same for someone who was vaccinated as for someone who wasn't. It seems hard to believe they would make such a basic error. Perhaps someone can explain what I'm missing?

Obviously I'm just some chump barstool epidemiologist, but to a simple man like me, it seems that if we have a vaccine that is 100% effective in preventing death, we won't have any COVID-19 deaths except among the minority of people who don't take the vaccine (which, to be blunt, is their problem; there are not enough of them to overwhlem the NHS). Even if it turns out to be a bit less effective than 100%, it's very hard to see how the kind of mortality figures in these studies can be justified.

The rate of transmission implied in these models doesn't seem plausible when 30% have already had the virus (according to Neil Ferguson), 85% have had the vaccine and it's summer, although both sets of modellers do seem to assume that Kent variant is extremely infectious. Maybe it is, but transmission isn't really the issue when people are protected from severe disease and death.

So why isn't this crucial factor included in the models?
UPDATE (23 February)
This pyramid of piffle has been formalised in a SAGE document and used to lobby against ending the NPIs in May. See this thread.

Monday, 8 February 2021

COVID-19 and vaping

In my fifteen years reading and writing about junk science, I have occasionally wondered if the day would come when a relative risk of 1% would be considered newsworthy. That day has finally arrived thanks to the Telegraph...
Vapers with Covid-19 up to 20 per cent more likely to transmit it than infected non-smoker, study finds 

Vapers who have Covid-19 are up to 20 per cent more likely to transmit the virus, spreading it in clouds of smoke, a study has found.

Bystanders exposed to low intensity expirations from an infectious vaper in indoor spaces, such as houses and restaurants, are one per cent more likely to catch coronavirus, researchers from Italy, Mexico and New Zealand found.

The study in question is a pre-print by Sussman et al. It's not an epidemiological study and it doesn't attempt to measure risk. Instead, it measures air exhalation and respiratory droplets in indoor places. It essentially tries to answer the question of how much more air vapers exhale than non-vapers and whether this has any implications for the spread of SARS-CoV-2. 

The answer is that vapers do exhale a bit more. One per cent more at normal low intensity, rising to 5-17 per cent at high intensity. From this it can be inferred that somebody who has COVID-19 and is vaping would exhale more potentially infectious droplets than someone who is not vaping. 

The authors are careful to point out that this needs to be put in context with other things people might do that would increase the amount of respiratory droplets they exhale. Talking, for example, doubles or triples the amount. Coughing increases it even more.

Unsurprisingly, the Telegraph has not run with the talking angle. The journalist (not Sarah Knapton for once) doesn't inspire confidence in her knowledge of the subject by repeatedly referring to e-cig vapour as 'smoke' and does not explain what the 'up to 20%' [sic] risk is compared with (ie. someone breathing but not speaking, singing, coughing etc.).

The researchers themselves come to a more measured and less sensationalist conclusion:

Risk assessments are essential to provide evidence based support for preventive and mitigating policies that have been proposed and enacted worldwide... Our risk assessment provides valuable information for safety policies in this scenario: low intensity vaping only produces a minuscule (∼1 %) extra contagion risk with respect to the control case scenario of continuous breathing. Safety interventions should consider that abstention from vaping would not produce a noticeable safety improvement, but could generate an undesired level of stress and anxiety under long term confinement. High intensity vaping produces a higher increase of relative risk, but still well below speaking and coughing.

In terms of keeping Covid-safe, they advise keeping a distance of two metres from vapers, as you would with another else.

And that's really all there is to it, but expect the 'vapers spread Covid' meme to circulate as a result of this irresponsible reporting (the Daily Mail has also got in on the act).

On a different note entirely, a bit of housekeeping. Has anyone else found that it takes ages for this blog to fully load up these days? The sidebar, in particular. Blogger made some 'improvements' a few months ago which made writing blog posts more difficult and seemed to slow everything down. I've considered leaving the platform, but I mostly use this blog to link to my articles elsewhere these days and I can't be bothered with the hassle.

I have been remiss in looking at the comments in the last year or so. Apologies for that. I used to get a email with each comment but those dried up ages ago. I have now put the Disqus moderation page in my bookmarks and will make more of an effort to read and reply to you in the future, so do keep them coming.

I mention all this at the bottom of this post because I know only loyal readers will get this far!

Sunday, 7 February 2021

The lockdown debate - a further reply to Toby Young

Toby Young has replied to my reply, so let's have one more go at this. 

Christopher Snowdon has now done what he failed to do in his original attack on lockdown sceptics in Quillette: he has engaged with the main plank of the sceptics’ case.

As I mentioned yesterday, the original article was never intended to be about the arguments for and against lockdowns. It was about the crackpots some lockdown sceptics have aligned themselves with. But now we have put all the stuff about false positives and casedemics behind us, we can get on with talking about the serious stuff.

In his response, Chris starts by making a pretty big concession: he acknowledges that the reduction in human interaction brought about by draconian stay-at-home orders could be achieved by people just deciding voluntarily to change their behaviour.

I don't see this as a 'concession'. On the contrary, it's an important part of my argument. It is obvious that people could stay at home without being told to. Toby thinks they would and that lockdowns are therefore superfluous, but if this were the case, you can't claim that lockdowns damage the economy. If you believe that nobody would go to the cinema during a pandemic, why complain about cinemas being closed? Would it not be better for the government to close them by law and compensate the owners and workers? 
You can't have it both ways. Either lockdowns have little or no effect on behaviour and therefore do not damage the economy, or they have a significant effect on behaviour - and therefore on infection rates - and damage the economy.

I do think that lockdowns are economically damaging - very much so - but that's because I believe they have a big effect on people's behaviour. I think Toby knows they have a big impact on behaviour too. I think he knows that if you open the cinemas and restaurants, people will go to them and that this will lead to more people being infected. He is right when he say that 'it’s absurd to claim that people would have just carried on as normal in the face of a global pandemic if they hadn’t been ordered to change their behaviour'. The problem is that we don't seem to change our behaviour enough to get the R below 1. 
This is partly because some people are downright irresponsible, but it is also because we don't have enough information upon which to act. Some people are wholly misinformed about the threat posed by the virus. The cranks I wrote about in my original Quillette article are partly to blame for that, but so too are public health agencies that have focused on handwashing rather than ventilation; the WHO flatly denied that SARS-CoV-2 was airborne in the early stages of the pandemic. 
But the real problem is that the nature of the virus makes it very difficult for individuals to assess their risk. The insidious thing about COVID-19 is that the incubation period can last up to two weeks. The government has a nice webpage where you can see how many people have recently tested positive in your postcode, but the figures are always five or six days out of date. You can think that your local area is low risk, but by the time you find out that it's high risk, it's too late. 

You do not need to view the public as 'mouth-breathing troglodytes who will march towards their own destruction' to see that people cannot make an informed decision under these conditions. 
Moreover, for a lot of people COVID-19 is not a serious health threat and so we are relying on them to act in an essentially altruistic way. A person might decide that they don't care if they get it, but that is not a purely self-regarding action. We need to stop the spread. When you have 100,000 people being infected every day, as we did at the end of December, and have to get the rates down, you cannot depend on people acting sensibly, responsibly and altruistically. If you could, there wouldn't be 100,000 daily infections in the first place.

When we say that lockdowns are largely ineffective – largely, but not completely – we are not questioning the basic logic of germ theory. Rather, our contention is that the illiberal things governments across the world have done in an attempt to control the virus have not resulted in fewer people dying than if they’d taken a more liberal approach, i.e., one that respected our individual rights and our status as rational beings capable of carrying out our own risk assessments.
Judging by the people on my Twitter timeline yesterday, quite a lot of sceptics do seem to question germ theory. They do believe that the infection rate rises and falls of its own accord, unaffected by restrictions on human interaction. That is what I call the hard version of the 'lockdowns don't work' theory. Toby is talking here about the soft version. I addressed that in yesterday's post. To summarise:
- Countries which have a lot of COVID deaths are more likely to lock down harder and longer. The high death rates in Britain, Spain, France, etc. do not mean that lockdowns don't work in suppressing the virus, albeit temporarily. 

- Plenty of countries locked down for a relatively short period of time, controlled their borders and have a low COVID death rate (Norway, China, Australia, New Zealand, Finland, etc.)

- Prolonged, sporadic lockdowns without achieving elimination are ineffective in the long term if there is no endgame, but we now have several vaccines. The debate about the current lockdown has to be seen in the context of the vaccination programme and yet Toby doesn't mention vaccines in either of his articles. 

Having asserted that lockdowns do not lead to fewer people dying, Toby asks...
Why is that, given that lockdowns do reduce human interaction? As I said in my piece, it may be because they bring about a net reduction in overall interaction, but unintentionally increase it in particular hot spots, where the virus is more easily transmitted. Or it could be because the heavy-handed, authoritarian attitude of most states has infantilized their populations, prompting them to take less responsibility for not spreading the virus than they would have if they’d been trusted to change their behaviour voluntarily.

Here, Toby seems to be conflating the hard and soft versions of the argument again. Lockdowns do reduce human interaction and they do reduce the infection rate. That has got nothing to do with the number of COVID deaths overall which are largely caused by infections that take place when lockdowns are relaxed.

Positive SARS-CoV-2 tests. England

I'm not quite sure what his argument is here, to be honest. If lockdowns make people increase their interaction with others in 'particular hot spots' or make them more irresponsible, shouldn't we see rates rising during lockdown?

Chris neglects to mention Sweden, which is not surprising because it poses some very awkward questions for people who believe the Covid death toll in Britain would have been far larger if we hadn’t imposed two lockdowns last year.
I mentioned Sweden in my initial article when I said...
No amount of comparing Sweden to its immediate neighbours will persuade me that the Swedes didn’t have a better 2020 than most Europeans.
I am happy to do so again. 

Unlike some lockdown sceptics, Toby concedes that Sweden had significant excess mortality last year, but says this was partly due to there being fewer deaths than normal in 2019 (the so-called 'dry tinder' effect). And so he lumps 2019 and 2020 together and triumphantly concludes that the combined death count from 2017 and 2018 was similar to that of 2019 plus 2020.
I'll let the actuaries judge whether this is a reputable methodology. I would only point out that developed countries are supposed to see age-standardised mortality falling year-on-year and they usually do. There was nothing particularly special about 2019 in Sweden. The UK also had its lowest rate ever in 2019. This does not mean there is dry tinder waiting to go up in flames.
Nevertheless, it is true that Sweden did not see the conflagration some people predicted. I wrote about this in September to make an anti-lockdown point. I was tired of people comparing Sweden to its immediate neighbours, all of which have much lower rates of COVID mortality. I was bored of people claiming that Sweden had got off the hook because of its population density which is, in fact, no different to some countries that have been very badly hit. 
My argument was that Sweden should be judged by its own standard. I pointed out that it had around 90,000 deaths every year and if it ended 2020 with 6,000 deaths from COVID - some of which would have happened anyway - it wouldn't be such a bad result in a once-in-a-century pandemic. The health service hadn't been overwhelmed. The Swedes had largely preserved their way of life, most of them seemed happy with the approach and in years to come, they, unlike most Europeans, will have something to say when they are asked what they did in 2020. 
I wrote that...
The Swedes always accepted that they would see a higher rate of mortality in the spring and summer than countries which locked down early. The argument against lockdown was that every country would see a similar number of deaths in the longterm and that it wasn't worth disrupting people's lives and livelihoods in an extreme way by quarantining the entire population. 

I never endorsed the belief of some sceptics that Sweden had reached herd immunity, but I did think that it would enjoy some protection in the winter from having allowed the virus to circulate among younger people in the summer. I wrote about this a week after the first lockdown ended in July, saying:

One country can look to the winter with less trepidation than most. Last week, a study suggested that 30 per cent of Swedes have built up immunity to the virus. It would help explain why Covid-19 has been fizzling out in Sweden. If a measure of herd immunity also helps them avoid the second wave, Sweden’s take-it-on-the-chin approach will be vindicated.

We've all made bad predictions in the last year (even Toby) and this was not one of my best. In my defence, I did conclude the article by saying that Sweden wouldn't look too clever if vaccines were produced in record time...

If a vaccine goes into production by autumn, the Swedes will look reckless. But that is not going to happen - and winter is coming.
The vaccines didn't quite go into production in autumn, but it was close enough to make herd immunity by other means look a more questionable strategy. 
Sweden has now had over 12,000 COVID deaths since the pandemic began and its second wave has been much worse than most. In December, 99 per cent of Stockholm's intensive care beds were full. Finland and Norway offered them medical assistance. The King of Sweden said the country had failed. I expect the economy to have been badly hit. Although the infection rate has fallen recently, it is still above the EU average and is - as always - much, much higher than that of it neighbours.

Toby wants to know why it wasn't even worse. I would say it's because the government pleaded with Swedes to keep themselves to themselves. Swedes are advised to work from home and mix only with people they live with or with 'a small number of friends or people from outside your household'. Swedish people take such advice seriously, but there has been some stick as well as carrot. In December, the government closed high schools and told people to wear face masks on public transport. 
Last month, the Swedish Parliament passed new legislation to 'allow the authorities to close restaurants, shops, and public transport in the country for the first time, and fine people who break social distancing rules.' Large gatherings have been banned for months. Gatherings of more than eight people have been banned since November. The sale of alcohol is banned after 8pm. All of this and more has played a part in Sweden having merely one of the worst second waves rather than having the absolute worst. 
Unlike Britain, Sweden hasn't had many cases of the more infectious B117 virus. Perhaps the large number of Swedes who have antibodies from being infected last year has also helped, at least marginally.

Whatever the reasons, Sweden is not Britain, just as North Dakota isn't New York. It is a myth that Sweden has relied on voluntary measures, particularly in recent weeks, but insofar as voluntary measures have prevented the total catastrophe some predicted in Sweden, they have never shown any signs of doing so in Britain. 

I'm happy to judge Sweden by its own standard, but I also judge Britain by its own standard. We tried relying on people using common sense in the autumn and it didn't work. We then tried a tougher approach with the tiers and that didn't really work either. The tiers had an effect in some areas and probably flattened the curve overall, but they weren't enough to stop cases quadrupling in December when the B117 variant took off. 
Our objective was to stop the NHS being overwhelmed. We failed. The infection rate rose and I am at a loss to see how adopting a more Swedish approach would have helped. By what mechanism would allowing more human interaction have slowed the spread?
Toby mentions again the US states that didn't lock down (although from a cursory look, at least one of them pretty much did). He admits that they haven't performed quite as well as he may have implied earlier, but says that most of them didn't fare too badly. In fact, most of them fared worse than average, and the ones that didn't were the extremely rural states of Nebraska, Utah and Wyoming. 
Why didn't North Dakota and Arkansas do even worse than New York and New Jersey on a deaths per million basis, he asks? 
I don't know, but I would imagine population density has something to do with it. New York City is the busiest and most densely populated city in the USA whereas the biggest city in North Dakota, by some distance, is Fargo (population: 124,662). Being an international travel hub, New York was hit by a massive epidemic of COVID-19 last spring and locked down as a result (London was in the same position and it is another reason the UK was hit harder than Sweden). 70 per cent of all the COVID deaths in New York occurred during that initial outbreak. Surely you can't blame those deaths on the lockdown? The lockdown was a response to the deaths and it worked well in bringing the numbers down. 
Presumably the sceptics think New York made a mistake and should have let nature take its course. I cannot see how that would have helped. What practical lessons should we have learned from South Dakota and Sweden in December as the hospitals filled up in Britain? It is one thing to argue that more mixing between households wouldn't have done much harm, but how can anyone argue that it would have helped?

In the final analysis, the best comparison is between England with a lockdown and England without a lockdown. Toby has an answer for this and it is here that we see the 'hard' version of the 'lockdowns don't work' argument return. Having started his article by denying that lockdown sceptics believe that 'infections will rise and fall within a given region, irrespective of how much human interaction there is', Toby argues that it is not lockdowns that make rates fall, but nature.

[Snowdon] admits that it’s difficult to prove this is causation rather than correlation, but claims that’s a more plausible hypothesis than the alternative – “that it is sheer coincidence that lockdowns have been accompanied by a sharp decline in case numbers in the UK and elsewhere time and time again”.

But I don’t know anyone who thinks this is “sheer coincidence”. Insofar as the decline in case numbers has coincided with lockdowns and other NPIs – and didn’t predate their imposition, as it did in the case of the UK’s first lockdown, which Chris more or less concedes – our contention is that it’s due to seasonality (which is why infections began to decline across Europe simultaneously last summer, regardless of when different countries lifted their restrictions) and the fact that the epidemic is beginning to settle into endemic equilibrium as more and more people get infected and then recover.

Sorry, but how is that different from sheer coincidence? Toby is saying that seasonality causes rates to fall and that this happens to coincide with governments bringing in lockdowns. 
It's a pretty ludicrous theory. Seasonality is a decent partial explanation for why COVID-19 rates stayed fairly low in the summer. It is not such a good explanation of why they fell dramatically in January
When, exactly, is Coronavirus Season supposed to be? It seems to be in October in Belgium, November in Slovenia, Lithuania and Italy, and December in Denmark and the UK. 


Looking at case numbers, France seems to have had its coronavirus season in October, but the epidemiological curve has not declined in the way you would expect. Estonia's season is still ongoing with rates high and flat whereas Ireland's season was remarkably short and sharp, with the disease spreading over Christmas and suddenly declining after 31st December for some mysterious reason (spoiler: lockdown).


All of these countries saw massive spikes in deaths last spring which strongly suggests that the virus was spreading rapidly in February. This year, however, sceptics want us to believe that February is the time when the virus naturally fades away. 

This is obviously nonsense. Seasons have an effect on SARS-CoV-2 only insofar as cold weather makes people more likely to be inside where viruses can spread more easily. It doesn't naturally disappear just because it's summer, let alone just because it's January. The number of COVID deaths has been rising in South America in recent weeks and South Africa has had a second wave in summer that was worse than the first wave in winter. Around the world, there have been major outbreaks in spring, summer, autumn and winter.

Toby concludes by saying that he enjoys debating me but that I need to 'stop tilting at straw men'. I enjoy debating him and I wish they were straw men. I wish he wasn't seriously claiming that the fall in infection rates seen around the world again and again at different times of year after lockdowns are introduced is the result of the seasons. This is not so much straw man and straw clutching.

Friday, 5 February 2021

Do lockdowns work?


Toby Young has responded to my Quillette article about COVID cranks. He says he 'won’t bother responding to [my] detailed criticisms of Ivor Cummins and Michael Yeadon because I don’t think the case against the lockdown policy stands or falls on whether their analysis is correct.'

Fair enough, but it was the claims made by such people that were the focus of my piece. Those who want a more liberal approach have been sullied by their association with such crackpots. That is regrettable because it gives the 'Zero Covid' fanatics the edge in the debate about when to end the current lockdown.

Toby's argument, which has been circulating on social media ever since the 'casedemic' theory collapsed so spectacularly, is that lockdowns simply don't work.

Our contention is that the whole panoply of non-pharmaceutical interventions (NPIs) that governments around the world have used to try and control the pandemic—closing schools and gyms, shutting non-essential shops, banning household mixing, restricting travel, telling people they can’t leave their homes without a reasonable excuse, etc.—have been largely ineffective.

How can this be? As far as I'm aware, one of the few areas of agreement remaining between the sceptics and the mainstream is that SARS-CoV-2 is a communicable disease that is transmitted from human to human, especially in poorly ventilated indoor spaces. If human interaction is severely curtailed, the infection rate can be reduced below 1 and the number of cases will fall.

This does not necessarily require lockdowns. People could do it voluntarily. But if they don't do it voluntarily, I would argue that government coercion is justified under the harm principle, a concept with which classical liberals should be familiar. 
So whilst lockdowns may not be a necessary condition for reducing the infection rate, they are a sufficient condition (assuming, of course, that people abide by the law). Toby is arguing that they are neither. In fact, he goes even further than that by claiming that none of non-pharmaceutical interventions work, not even travel restrictions.

He concedes that there are 'some peer-reviewed studies published in reputable journals seeming to show that these measures reduce COVID-19 infections, hospital admissions, and deaths'. He only links to one of them, but there are many others. In any case, he says that 'most of these rely on epidemiological models that make unfalsifiable claims about how many people would have died if governments had just sat on their hands'. 

Instead, Toby links to a blog post which supposedly reviews 30 studies which provide 'evidence that lockdowns don’t work ... not based on conjecture but on observing the effects of lockdowns in different countries.' I have seen this blog post touted around Twitter for weeks. Of the 30 (actually 31) 'studies', only seven have been published in journals in the last twelve months. Many of them are pre-prints that have not been peer-reviewed. Some are self-published PDFs. Three are newspaper or magazine articles. One is a blog post. Many of them have only a tenuous relationship to the question of whether COVID-19 lockdowns have worked. One of them was published in 2006, another in 2008. Quite a few of them involve the kind of modelling Toby says is no good.

Of the seven published studies, one is only available as an abstract and seems to be more of an opinion piece than a research paper. One is about quarantined US Marines and has little relevance to the question at hand. Another is a research letter that is almost entirely irrelevant. 

Only five of them broadly support Toby's argument. One of them found that various factors, such as life expectancy, are associated with the number of COVID-19 deaths in different countries, but lockdown stringency isn't. This study came to a similar conclusion. This study from New Zealand, where there have been only 25 deaths from COVID-19 so far, makes the bold claim that 'lockdowns do not reduce COVID deaths'. 
Another study looked at the factors associated with higher Covid death rates at the national level and found that 'border closures, full lockdowns, and a high rate of COVID-19 testing were not associated with statistically significant reductions in the number of critical cases or overall mortality'. However, it also found that full lockdowns were associated with higher recovery rates which suggests that 'full lockdowns and early border closures may lessen the peak of transmission, and thus prevent health system overcapacity' (which is the justification for lockdowns in the UK)

Finally, there is this study which concluded that lockdowns suppress the virus in the short term, but lead to more deaths in the second wave 'unless herd immunity is achieved by vaccination, which is not considered in the model'. 

Vaccination is the crucial missing variable. There are two versions of the 'lockdowns don't work' argument. I'll come to the 'hard' version in a moment, but the 'soft' version says that, in the absence of a vaccine, the virus will infect a certain proportion of the population sooner or later so you might as well take it on the chin. Given the social and economic costs of going in and out of lockdown indefinitely, there is a lot of truth to this and the handful of peer-reviewed studies in the blog post Toby links to address that issue.

But there are two big problems with it. Firstly, many lockdowns - including the ones in Britain - were not so much designed to reduce the overall death toll as to prevent the humanitarian disaster of having many millions of people infected simultaneously and overwhelming the health service (which would itself lead to more people dying). If you accept that avoiding that is as a legitimate policy goal, using lockdowns to flatten the curve makes sense.

Secondly, we have multiple vaccines now. Unlike in March and November, it can no longer be argued that lockdowns merely delay the inevitable. Lockdowns do work if you have a destination.

Saying lockdowns don't work because they don't get rid of the virus is to argue against something nobody has claimed. We always knew that the spring lockdown would only push the problem into the winter. Neil Ferguson's much hated (by sceptics) model for Imperial College in March made that perfectly clear. The government was buying time, hoping that salvation would come in the form of Test and Trace (it didn't) and vaccines (it did). 

The 'hard' version of the argument says that lockdowns don't even work in the short term. They don't reduce the infection rate, even temporarily. Given the existence of germ theory, this is an extremely difficult idea to swallow and yet Toby seems to have done so. With reference to his '30 studies', he writes:

What these data seem to show is that the SARS-CoV-2 epidemic in each country rises and falls—and then rises and falls again, although less steeply as the virus moves towards endemic equilibrium—according to a similar pattern regardless of what NPIs governments impose.

This is not true. Even the studies that can be used to support the soft version of the anti-lockdown argument do not support this argument, which amounts to 'viruses gonna virus'.  

If lockdowns work, you’d expect to see an inverse correlation between the severity of the NPIs a country puts in place and the number of COVID deaths per capita, but you don’t
Toby is now conflating the hard and soft arguments. The test of whether lockdowns reduce the infection rate is whether the infection rate falls after a lockdown is introduced, not whether the country has a high or low COVID death rate overall. Lockdowns can work (in the sense of reducing the number of cases in the short term) in countries that have already had many COVID deaths, as Britain and much of Europe have shown in the last twelve months. Countries lock down hard precisely because they've got high death rates.
On the contrary, deaths per million were actually lower in those US states that didn’t shut down than in those that did—at least in the first seven-and-a-half months of last year.
This is not relevant to the question of whether lockdowns reduce the caseload, but it's worth noting that 'at least in the first seven-and-a-half months of last year' is doing a lot of heavy lifting here. Toby's source is a blog post from the American Institute for Economic Research published in August. It looks at 'the only seven states to never issue stay at home orders' (Utah, South Dakota, North Dakota, Nebraska, Iowa, Wyoming, and Arkansas) and claims that they are 'amongst the top performers in terms of minimizing deaths per capita'.
It didn't age well. By November, the pandemic in North Dakota and South Dakota was 'as bad as it gets anywhere in the world'. Both states have an even higher COVID-19 death rate than the UK. Arkansas's COVID death rate has risen from 21 per 100,000 to 166 per 100,000. Iowa's is 160 per 100,000. Nebraska and Wyoming have a similar death rate to California, which is to say a high one. With the exception of Utah, all the 'top performing' states have seen COVID-19 kill at least one in a thousand citizens so far. 
(Incidentally, the current smiley favourite, Florida, has a COVID death rate of 127 per 100,000, putting it on a par with Spain and Peru. Not a massive success story.)
So do lockdowns reduce the infection rate or is the virus gonna virus?  Thanks to mass testing, we have accurate data on case numbers for many countries. People tend to get tested around 5-10 days after they get infected (ie. when they get symptoms) so we can see whether infection rates fell after a lockdown was introduced by seeing what happened to the case numbers a week or so later.
Here is France, for example. The lockdown began on 31 October and cases started to fall steeply from 8 November. The lockdown began to be eased on 28 November after which case numbers began to rise.


This is Israel. It had a big spike in cases in August and September (contrary to the theory that COVID-19 is a seasonal virus) which it addressed with a lockdown beginning 18 September. Cases began falling from 27 September. In the subsequent wave, it introduced a hard lockdown on 7 January and case numbers fell from the 17 January. 


This is the Czech Republic, or Czechia as it now prefers to be known. It introduced a lockdown on 22 October and cases started falling after the 27 October. A subsequent lockdown began on 27 December, with case numbers peaking on 7 January.


This is Ireland. It had a huge outbreak over the Christmas period which was rapidly brought under control by a lockdown that began on 31 December. Case numbers peaked on 8 January. 

This is Wales. It introduced its 'firebreak' lockdown on 23 October. Cases peaked on 29 October before falling by half. 

I could go on, and you can look at the figures yourself if you still doubt me, but let's finish with England. England had a lockdown on 5 November, case numbers peaked on 9 November and then fell by half. It has been claimed that infections started falling just before the lockdown, but that's not obvious from this data. I remember thinking at the time that rates looked pretty flat and being suspicious of Chris Whitty's dodgy dossier, which is why I opposed that lockdown, but there was no sign of rates falling and there was certainly no reason to think they would fall by half. Why would they?

The third lockdown began on 6 January, but case numbers started falling at the same time which suggests that infections peaked at the very end of December or the very start of January. Other evidence confirms this and sceptics have leapt on this as evidence that lockdowns don't work.

Actually, it is evidence that lockdowns are not the only thing that works - and the other things that work are very close to being lockdowns. London and large parts of the south east were put into Tier 4 on 20 December. The schools were closed for the Christmas holidays at around the same time. This meant that the most heavily populated parts of the country were already in lockdown in all but name. Everywhere else was in Tier 3. There was not a pub or restaurant open in the country. Many workplaces were closed over Christmas. 

We can see from the mobility data that things quietened down over the Christmas period. It was a very unusual Christmas.

If you want to argue that closing all the schools and most of the workplaces and putting the whole country in Tiers 3 and 4 has similar effects to a full lockdown, you won't get much argument from me, but don't pretend infection rates were falling under a laissez-faire regime.

Alternatively, you can argue - as Toby appears to be doing and many smileys certainly do - that infection rates are unaffected by any restrictions on human interaction and that it is sheer coincidence that lockdowns have been accompanied by a sharp decline in case numbers in the UK and elsewhere time and time again. He seems to think it was a fluke in January, a fluke in November and a fluke in March.

Incidentally, Snowdon’s claim that the first British lockdown reduced COVID infections is easy to debunk. You just look at when deaths peaked in England and Wales—April 8th—go back three weeks, which is the estimated time from infection to death among the roughly one in 400 infected people who succumb to the disease, and you get to March 19th, indicating infections peaked five days before the lockdown was imposed.

This theory remains contentious as we didn't have mass testing at the time. When BBC More or Less looked at the issue, they found it depended on whether you used the mean or modal average. But let's say it's true. People were told to avoid unnecessary travel and contact with others on 16 March. Vulnerable people were told to shield themselves for twelve weeks. Pubs, restaurants, gyms and schools were closed by law on 20 March.
It is possible that this was enough to bring R below 1, but it is equally possible that R would have gone back above 1 after the initial panic subsided and people resumed human interaction. Either way, you have to accept that human interaction spreads the virus. If you're worried about the social and economic damage done by people not going out mixing and socialising, it shouldn't really matter whether it is the result of voluntary or mandatory measures. If you don't think lockdowns make much difference to people's behaviour, they can't make much difference to the economy. You can't have it both ways.
If, on the other hand, you want people to be mixing and socialising, don't pretend that the way people behave in the days leading up to a lockdown are representative of how they would behave if there was no lockdown at all. 

And if your argument is that human interaction is irrelevant and the virus is gonna virus, then there's nothing left to be said. Wallow in ignorance if that's your scene, but don't expect be taken seriously by anyone outside the smiley cult. 

The number of cases doubled in England in December to 30,000 a day, which is more than we had when the November lockdown was announced. In the second half of the month, they doubled again. We have seen the consequences of that in recent weeks, with more than a thousand COVID deaths a day and nearly 40,000 people in hospital with the disease. 

Imagine if it had doubled again. And again. At some point it would have petered out, but with 80% of the population vulnerable to catching it - and it being the middle of winter - there was no reason to think that exponential growth wouldn't continue for at least a little while longer. 

Presumably, those who believe that non-pharmaceutical interventions are 'largely ineffective' believe that the infection rate would have fallen by two-thirds in recent weeks, as it has, if we'd have carried on as normal. They must also believe that rates would have quadrupled in December, as they did, if we'd been in full lockdown from late November. They must think it is just good luck that SARS-CoV-2 is no longer circulating in Wuhan and New Zealand. Virus gonna virus, right? It's got a mind of its own.

It's absurd thinking, but the sceptics have finally found an argument that cannot be categorically disproved. Lockdowns have a scientific rational: you can't transmit a virus to people you don't meet. Contrary to what Toby says in his article, they also have historic precedents: during the Spanish Flu, cities such as Philadelphia closed shops, churches, schools, bars and restaurants by law (they also made face masks mandatory). And now we have numerous natural experiments from around the world showing that infection rates fall when lockdowns are introduced.

In the final analysis, the smileys yelp 'correlation is not causation'. It never is. The link between smoking and lung cancer is still only a correlation, but there comes a point when the correlations are so strong and the alternative explanations are so far-fetched that it becomes proof in the mind of any fair-minded individual.
But even though sceptics lack a convincing hypothesis to explain why lockdowns don’t work, I don’t think we’re obliged to come up with one. Surely, the onus should be on governments to show that lockdowns work if they’re going to suspend their citizens’ civil liberties? For me, as a classical liberal, this is the most decisive argument against the draconian controls democratic governments have imposed in the hope of mitigating the impact of the virus.
To be fair to the government, it has tried to persuade people and it has succeeded in most cases - which is going to have to suffice when a democracy is faced with a collective action problem. Toby complains that the case for lockdowns rests on 'epidemiological models that make unfalsifiable claims about how many people would have died if governments had just sat on their hands'. But you don't need a model to know that an uncontrolled epidemic is going to get out of control. The models try to quantify how bad things will get - not always accurately - but the basic assumption that a communicable disease will spread exponentially unless action is taken should not be up for debate. 
Unless there are certain agreed facts, there is no room for a productive conversation. We have a highly infectious disease that kills around one per cent of those who contract it and which is a huge drain on healthcare resources. Most people have not yet contracted it and therefore do not have immunity to it. It is airborne and spreads via human contact. Whenever restrictions have been relaxed we have seen rates rise, particularly in the winter. Voluntary behavioural change may have been enough to control the virus in some parts of the world, at least for a while, but it has never been enough to produce a sustained fall in the UK. Around 20% of the population have had the virus, of whom over 100,000 have died. If 40% got it, 200,000 would be dead. If 60% got it, 300,000 would be dead. And so on.
This is just science and the remorseless logic of exponential growth. If the sceptics want to argue with biology and mathematics, then I'm afraid the onus is on them to make their case. Both sides are dealing with counterfactuals and therefore with unfalsifiable propositions. Absolute proof is impossible, but those who believe that lockdowns reduce the infection rate have a solid theoretical basis for their view which is backed up by ample empirical evidence from around the world. 

The sceptics, by contrast, have fallen for every crackpot theory going for the last six months and have finally settled on a claim that can never be fully demolished; the idea that whatever happens would have happened anyway. Thanks to mass vaccination, the virus should fade away for good over the next few months and the sceptics can tell us forevermore than the government overreacted to a December spike of a virus that was already on its way out; that a virus which naturally peaked in late March last year naturally peaked in early January this year. And you will never be able to convince them otherwise.
Toby makes a fair point when he says that the government has never produced a solid cost-benefit analysis, but such an analysis would be rejected out of hand by the sceptics because it could only be based on 'unfalsifiable claims about how many people would have died'. Given that the average person who dies from COVID-19 loses, on average, ten years of life, and that much of the economic damage is caused by people's response to the virus rather than the lockdown, any realistic estimate of how many deaths have been prevented - combined with the standard valuation of a quality-adjusted life year - would, I am sure, show that this lockdown has been worthwhile. 

That could change as the lockdown wears on, the vaccinations kick in and the number of deaths being prevented declines. At that point, the public debate would benefit from some level-headed economic analysis from lockdown sceptics, but who, by that time, will still be listening to them?

UPDATE: This debate was continued here.