The PM is doing what he thinks is best for public health, yet the modelling is much too uncertain.

Following my article yesterday on The Telegraph, I have re-published it here:

Our Prime Minister faces a nightmare scenario. Official advice on NHS capacity is that “even surge capacity is burnt through in all regions but London in the next four weeks” and “on the current trajectory the NHS will not be able to accept any more patients by Christmas week”. With greater restrictions taking three weeks to have an effect, it seems only immediate action can salvage the situation. Facing this advice, what would any Prime Minister do?

The consequences of our decisions either way could be existential. MPs are being asked to vote to impose huge costs on their constituents, but the alternative, they are told, is the collapse of healthcare provision across the country and a sustained high level of deaths. We are working under extreme pressure at the intersection of science, policy and politics. Many members of the public are asking MPs to vote against this lockdown to protect their non-Covid health and livelihoods. But regardless of any rebellion, Boris will win: Labour are in favour.

Doubtless, the Prime Minister is among the least likely advocates of restraints on liberty. But his choices are not free: he serves the public within the context of advice. I accept the goodwill of those providing that advice, but experts are human. Pressures bear even on the most sober, scientific and impartial person. Knowledge in a pandemic is incomplete and uncertain.

That’s why we need competitive, multi-disciplinary expert groups, with challenges from devil’s advocate “red teams”. On Saturday, I took just such a “red team” into Downing Street, but the session was inconclusive: we could not show the advice given by officials to be wrong. By Sunday, however, Professor Carl Heneghan had dismantled the death models used to justify lockdown as outdated. Red teams work.

Since the start of the outbreak, much of our policy has been model driven. I am today releasing a report on methodological issues in epidemiology by Mike Hearn. Yesterday, I asked select committee chairs to consider the issues. Models often contain internally inconsistent and non-replicable numbers, use insufficiently large data sets to derive critical inputs, and the bounds of uncertainty are often either not reported or have a very wide range. In one case, a prediction was changed to “20,000 deaths or much lower”. Academic software quality is notoriously poor, and models are often not validated by the actual course of an epidemic, yet they still drive policy. Models departing from the “accepted” viewpoint are often rejected for publication. Change is essential.

The best argument for the Government’s policy is this. The natural R of this disease is probably about 2.5. Getting it down to 1.5 is relatively easier than getting it down from 1.5 to below 1. If R is left at 1-1.5 at a high level of incidence, that may institutionalise a plateau with a high level of infections, and with the hospitalisations and deaths that follow. That is the phenomenon that could lead to a lengthy period with a high level of hospitalisations which progressively prevent hospitals from treating other conditions.

The judgment call is that if one believes the fundamentals of the disease will be changed through testing, treatments and vaccines, then it may be an advantage to have a month of painful lockdown now to reduce prevalence and avoid the elevated plateau of disease later. Clearly officials are optimistic about changing the fundamentals soon. Otherwise, I think they would not recommend lockdown.

Unfortunately, I’m not convinced.

Compliance must be high, a month may not be long enough, the breakthroughs may not come, and so on. And if we really are locking down for this purpose, keeping schools open is a huge compromise. Most importantly, the cost-benefit is today a guess.

One thing we can say for sure is that the Prime Minister is courageously acting against his own instincts to do what he thinks right in the public interest. It is an act of extraordinary character which I admire.

I am sorry that I do not feel able to impose the undoubted costs of lockdown on the basis of the necessary balancing judgment calls. It is with a heavy heart that I plan to vote against this measure, but I will condemn no one for supporting lockdown if they think it will minimise harm.

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