Another scientific case for the circuit-breaker lockdown

An interesting article from Unherd – click here for full article, which relates to England, but can be applied to the forthcoming Welsh fire-break.

In the highly polarised debate over lockdowns, Professor Karl Friston is somewhat hard to place. He’s a member of “Independent SAGE”, a group of scientists set up to critique the Government advice which has been accused of being stocked with Left-wing activists, and he’s a signatory of the new “John Snow Memorandum” opposing the ideas around herd immunity of the Great Barrington scientists. So far, so orthodox. On the other hand, his concept of immunological “dark matter”, which he floated earlier in the summer, sent his scientific stablemates into paroxysms as it seemed to suggest that not everyone was equally susceptible to the virus. The claim was that the true portion of people who are not even susceptible to Covid-19 may be as high as 80%; this is now one of many concepts that seemed heretical at the time but is now uncontroversial.

Although Professor Friston appears to be on the Establishment side of the debate, his ideas seem to me to be very similar to Professor Sunetra Gupta in terms of levels of immunity in the population. His expertise is complex mathematical modelling of biological processes — he calls it “dynamic causal modelling” — which gained him global renown when applied to neuroscience and which he is now applying to the pandemic.

According to Professor Friston, the “secondary wave” is unfolding largely as predicted — see the blue line below, taken from his report in June (the 32 months refers to the typical length of time he is assuming immunity lasts). If we proceed as we are, without national lockdowns, the model suggests that daily deaths will soon peak and start coming down. He now thinks the total deaths from this second wave will be closer to 2,500 than 6,800.

Figure 1: June projection for a second wave (Karl Friston)

Friston was recently asked by the Independent SAGE group to model the effect of a two-week national “circuit breaker” lockdown, and the results (seen by UnHerd but not yet published anywhere) he found “slightly counterintuitive”.

The first finding is that a two-week national lockdown does not, as he had hoped, bring transmission right back down to zero. “I had thought that a national circuit break would ‘crush’ the curve,” he tells me. “However, I was wrong: although the secondary peak is suppressed, it leaves us with a chronic fatality rate that is slightly higher than the summer.”

In this respect, his findings could be taken as an argument against such a circuit-breaker, with all the disruption and damage it could cause. “The modelling suggests that the window of opportunity for suppression has now passed,” he says. He concludes that the effect of a circuit breaker, in the absence of new factors such as a much more effective test and trace system, would not be to reduce the total deaths in the long term, only delay them. At some point in the future, the total deaths for the two scenarios (with and without a circuit breaker) will converge.

When Professor Friston modelled the longer term death forecasts with — and without — a two-week national circuit breaker, the difference was stunning. The blue line shows deaths without a circuit-breaker to the end of 2022 and the green line shows it with a circuit breaker and improved contact tracing:

Figure 2: Death rate

According to Friston, the circuit break will have the effect of stopping the second wave in its tracks and interrupting the cycle of tertiary waves, fast-forwarding us into a state akin to what epidemiologists call “epidemic equilibrium” — ie when a virus continues to circulate but at a manageable, more consistent level.

With the Welsh “fire-break” lockdown commencing on Friday for 17 days, we should have ample evidence to prove if this theory is correct or not in the coming months over the winter. Time will tell.

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