Why lockdown? 1st draft

Why lockdown?

The readiness with which the governments of the world jumped into the lockdown strategy was really remarkable, as it is probably the most economically damaging and expensive anti-epidemic strategy available. Governments will be held accountable for this. Where did they get the idea from? Why did they almost all do it? Is it worth it? Could it have been nuanced and done more effectively?

I will add to this piece in forthcoming weeks as the Victorian second lockdown proceeds.

The counterfactual

In early April Pandemicia put up the proposition that as there was no chance of eliminating the virus in the USA and Europe and it was already affecting anywhere up to 20% of the population, then it might be better to forget about lockdowns and devote all efforts to protecting the elderly and vulnerable, as this is where the deaths were occurring. There is no particular reason why the entire community should be targeted for something that seriously affects only an easily identifiable subgroup. 

Exactly how one was going to protect the target group was far from clear, short of sending everyone over 65 or with co-morbidities to their own island - since if the virus is in the general community, sooner or later everyone will get it. Temporary measures might however be effective while the disease is researched and as the medical community searches for treatments or a vaccine.

A number of senior scientists, medical figures and economists had already said more or less the same thing - that lockdowns were prohibitively expensive and didn't do much (though few of these lockdown deniers seemed to be interested in protecting the elderly). 

Comparison with Spanish influenza

As no-one had much of a clue about what to do with a virus that had no treatment, the ideas in the early days of the pandemic came from the last few pandemics of any size - most notably recent H1N2 outbreaks, Swine flu H1N1, and the killer H1N1 Spanish Influenza pandemic in 1918-19, with 50 million deaths. 

Death rates by age, Spanish Flu and Covid-19

In 1918-19, as well as killing young children and people over 65, H1N1 also killed 25-34 year olds in quantity. Therefore those communities that protected their workforce by lockdown and social distancing were also able to recover their economies more quickly. This economic argument did not apply to COVID-19 - instead young people were asked to sacrifice their life chances for the elderly, with no economic incentive apart form what governments could offer.

A fair amount of academic work on social distancing had already been done for influenza outbreaks (Rashid et al, and it was widely accepted as a useful non-medical intervention. 

Lockdown was a different matter and was not part of the medical canon, though it does belong to the long tradition of quarantine. It had not really been employed since 1919. The Chinese employed full lockdown very successfully in their Wuhan outbreak. The Italians had a more stuttering response but eventually followed suit. Some  governments such as the UK and Sweden were more hesitant. Following public outcry by experts, the UK eventually did so and the results were similar to Italy.  

One of the main reasons advanced for lockdown was the "flattening the curve" scenario - which clearly came from modelling, as coronavirus actually does not have a curve but is a series of aggregated outbreaks. Some rough theoretical modelling demonstrated you could keep slowing down the advance of the disease by a series of punctuated lockdowns if you could reduce transmissions by 75% - which might stop your medical facilities being overwhelmed and also might buy time while you waited for some form of treatment to emerge. Since medical facilities and undertakers in Italy, Spain and New York were overwhelmed, causing considerable distress among medical staff and relatives, this seemed plausible. 

No country except Australia has actually done a comprehensive second lockdown; the consensus being that the public would never tolerate more than one severe restriction, and you had a single chance to ramp up your preparations. In practice, after panic-buying of equipment, all the Western countries did this fairly easily, and they ended up with a considerable excess of  ICU beds and ventilators, with a high testing capacity though still short of PPE.

In Australia - even though the second lockdown in Victoria has come a little ahead of the graph schedule, it has not been about resources, but rather that the country went very close to eradication, and suffered a major breakout as soon as it relaxed rules. It has become a matter of national pride and determination not to follow Europe and the USA but to match the New Zealand effort and keep the disease suppressed if not eradicated.   

Did it work? What happens at the end?

 It was obvious everywhere that the lockdowns caused an immediate substantial reduction in infections. Around 5-9 days after lockdown, the exponential advance in confirmed cases stopped. Another 9-14 days after that, cases began to fall, either rapidly or slowly. Pandemicia's original call of a top to the Australian epidemic on April 1 was able to be made in part due  to these considerations.

The end of lockdown in countries that had suppressed the disease down to single-digit new cases left them in the same situation as they were at the epidemic onset - about to turn to fast outbreaks. This has mostly happened except when the authorities jumped on all outbreaks fast enough with test, trace and isolate.

The end of lockdown in countries that had a really significant outbreak but have pushed new cases down to about 100 per day has been mixed. Some have been able to maintain a falling case rate, probably because something similar to herd immunity has already been reached. In others like Iran and Israel, a second blister emerged. 

The end of lockdown in the USA resulted in an immediate resumption of the rapid rise in cases in those parts of the country that had not yet had a full epidemic, though it has yet to be associated with a similar rise in deaths.

Discussion

When COVID-19 hit in force, absolutely everyone except a few Asian countries was caught by surprise. Governments turned immediately to their chief medical officers who turned  to any epidemiologists they knew. This was not Bletchley Park and there were few problem solvers nor original thinkers amongst the senior team. So they regurgitated what they knew about old pandemics, none of which had much similarity to COVID-19, or they dragged out some old epidemiological demonstration models that had nothing to do with a real epidemic.

After 30 years of populism and everyone being their own expert, there was a sudden turning to expert opinion that everyone wanted to hear - just when the experts knew little more than the public. 'Lockdown' was just one of many new memes that was seized upon by  government, social media and the press. It accompanied the equally unpleasant sounding 'herd immunity', the fairly silly 'flattening the curve', and the always impending and completely misunderstood 'second wave' - always sounding like the surfer dream that there is always a bigger one 'out the back'.