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On 19 March, the Prime Minister confidently opined that “we can turn the tide [of Covid-19 infection] within the next twelve weeks”. By 1 July, Professor Neil Ferguson was warning, on Radio

4’s “Today” that it will be “important to get the next six months right”. A first step towards doing so might be to compare predictions of “the Science” with what has happened so far. The

numbers don’t add up. The implications for long-term strategy need to be assessed. In early March, the Imperial College Ferguson report with its predictions for Covid infections in the

United Kingdom was central to the Government’s lockdown strategy. The model predicted a rise, leading to lockdown, followed by a fall and release of restrictions after about twelve weeks, in

line with the PM’s estimate. Far from this being the beginning of the end, it is more likely the end of the beginning, for what was not widely advertised at the time was that the report

predicted repetitions of this sequence, which would likely have to continue for well over a year. We are just completing the first of these cycles. Ferguson’s team predicted infections would

peak three weeks after mitigating measures were initiated and then fall away into July. This is roughly similar to what happened in reality, but the numbers of ICU cases differ. When we

look beyond the headlines and delve into the fine print of the report, we can see a reason why. The curve which seems to have driven the government’s response to the crisis, assumed that

only 50-70 per cent of people would go along with having their freedom of movement restricted. Ferguson’s report warned that “introducing such interventions too early risks allowing

transmission to return once they are lifted” and it is necessary “to balance the timing of introduction.” Recall that it was concern that the public might tire of the restrictions and choose

not to follow them when the curve reached its peak that caused the authorities to hold off. In the model, measures were introduced when ICU admissions hit 100 per week. When lockdown

eventually began, however, on 23 March, the rate was already at 100 cases per _day_. Fortunately, the public turned out to be more supportive of lockdown than the model had assumed. Had we

known back then that 90 per cent would have followed the guidance, the government might have been less hesitant in implementing the measures. It is now estimated that some ten thousand fewer

deaths would have resulted to date had lockdown started a week or so earlier. This model of how a virus can be controlled in a population is, however, only part of a government’s needs. It

is not “The Science” — a favourite get-out-of-jail card used by politicians — but a single albeit important contributor to a bigger problem. It does not consider the effects of lockdown on

the economy, on education, or on a host of other factors that will affect the longer-term health of the nation, both literal and metaphorical. How to weigh the conflicting demands of this

piece of science — which was prepared at a time when there was serious likelihood of the NHS being overwhelmed — with those that would benefit from releasing the lockdown, is for government

to decide. Outside the model, when applied to estimate mortality, are “second order” effects, such as: People whose “conventional” hospital needs, such as cancer therapy, are interrupted or

delayed leading to deaths in coming months; school closures, interrupting the education of a generation, the effects of which will be felt for years to come but in ways that are hard to

gauge; or disruption of the economy, which will impact livelihoods, increase poverty and death rates in ways that are indeterminate but likely to be both widespread and long lasting. How

much weighting is given to these is a decision that goes beyond this piece of “The Science.” The public’s willingness to enter lockdown was driven in part by fear, as media were filled daily

with images of those killed by the virus. This fed an impression that death walked the streets. Which brings me to the second quantitative message present in the data, though there seems to

have been no widespread attention drawn to it: the chance of you experiencing a debilitating illness is small. At the start of July, in the United Kingdom Covid-19 is linked to roughly 44K

deaths with some 312K infections diagnosed. Meanwhile, buried among the statistics presented at the daily briefings in Downing Street was an estimate of the total number of infections. On 11

May the Chief Scientist said Covid-19 had already infected some 4 per cent of the population; by 1 July, according to Professor Ferguson, this total had reached possibly 8 per cent, while

in London a staggering 20 per cent could have had the disease. The remarkable implications of these figures have been met with a deafening silence. This translates to nearly 2 million cases

having occurred in London alone, and up to 5.5 million in the United Kingdom. While this is far too small to bring us anywhere near herd immunity, for which some 50 million infections are

thought necessary, it is huge compared to the number of cases serious enough to have been noticed, let alone to have led to death. In effect, over 90 per cent of Covid-19 infections have

been too mild to register. While there has been much discussion about the qualitative features of the disease’s impact on society, the quantitative nature of this disease seems, from these

figures at least, to be less of a threat to health and life than the public believes. This all depends, however, on the reliability of the total infection figure. What is it? For it seems to

me that this is key to planning how society at large progresses from here, until either a vaccine against the disease or some way of mitigating its effects are available. This conclusion is

similar to Gerald Baker’s (_Times_, 2 July) but his recommendation — “With proper targeted protection of the vulnerable it would probably not have been necessary to close down the economy”

— begs the question of which groups are the “vulnerable.” It is hard to disagree with Ferguson that we must “get the next six months right”; to do so, we need to understand the first three

months.