February 19, 2021

How long will this virus be with us? Earlier this week, the scientific journal Nature published an international survey of 119 Covid-19 experts — immunologists, virologists and epidemiologists — about the likely future of the virus and the human race. Almost nine in ten of them thought it likely that Covid would become endemic in the human population, continuing to circulate at least in some regions for many years to come. Six in ten thought it “very likely”. Only 6% thought that an unlikely scenario.

This makes the goal of complete virus elimination — Zero Covid — look unrealistic, at least in the short term. But unfortunately for the Prime Minister, who is expected to announce Britain’s “roadmap” out of lockdown on Monday, it by no means answers the question of which route he should take.

When it took scientists less than a year from Covid’s outbreak to create a working vaccine, and not just one but several, relief was twofold. In one sense, the prospect of an end to both the disease’s merciless death toll and the atomised grimness of human life brought general euphoria to the darkness of November. But for politicians and others tasked with steering society between the Scylla of social destruction and the Charybdis of Covid itself, there was a different relief.

Without a workable vaccine, they faced the impossible task of extricating society from a cycle of lockdowns, knowing that doing so would probably mean a rise in deaths that could make the earlier stringent measures seem futile. With vaccines, though, normal life could return without sacrificing tens or hundreds of thousands more lives.

But, as Number Ten is now discovering, the introduction of vaccines creates an entirely new set of dilemmas for governments across the developed world. For if it is possible, even in theory, to bring the infection rate so low that “test, trace, isolate” is a practical way to control the disease on its own, the current lockdown is probably the last chance to do that. Yet doing so would mean continuing the current stringent measures for months, long after the most vulnerable have been vaccinated; there are even rumours that the Government wants to maintain the current lockdown until cases (not hospitalisations) fall below one thousand a day — less than a tenth of the current figure.

But the first, and subsequent, lockdowns were justified as measures to keep deaths and serious cases at a level that wouldn’t overwhelm health services. If vaccinating the most vulnerable parts of the population breaks the link between cases, hospitalisations and deaths — bringing the impact of Covid down to the level of a seasonal illness like flu — does it matter if infections remain as common as its cousin, the common cold, which infects the average adult two or three times per year?

This is the new dilemma facing policymakers and, though science can and must inform it, it is at heart a political question. Even government scientists are starting to express frustration about the UK government’s apparent unwillingness to grasp that nettle. As Professor Dame Angela McLean, Chief Scientific Advisor to the MoD and a member of SAGE, told a Science and Technology Select Committee on Wednesday: “It’s one of the things we have cried out for again and again. Could somebody in a position of political power tell us: what is an acceptable level of infections?”

She was answering a question about whether, as Chief Medical Officer Chris Whitty has suggested, we will have to live with Covid as we do with flu and other infectious diseases. And she agreed that “other infectious diseases that we put up with are probably a reasonable starting point”. But this in itself still doesn’t solve the political question, because, as Professor McLean pointed out, bad flu winters can still be remarkably deadly. It still comes down to a matter of judgement.

In recent UK history, the worst years for flu deaths were 1976 and 1999, when more than 60,000 people in England and Wales died from influenza or pneumonia. The best year in the last century was 1948, with under 20,000 deaths. That leaves a range of 20,000-60,000 deaths per year, up to half the Covid casualties so far, and up to 10% of the pre-Covid annual death toll.

After the last year, would that feel like an acceptable number of deaths? Conversely, would we accept another year of lockdowns to reduce the toll of Covid from 60,000 to 20,000? As Professor McLean said: “The question of what is acceptable is not a scientific question. That’s a question for the whole of society.”

It’s worth noting, however, one caveat provided by epidemiologist Professor Mark Woolhouse, who is also a member of SAGE: “Whatever the answer is, it’s not zero.” That is, he explained, because if you take the view that every Covid death is unacceptable, “you are writing a blank cheque to do any amount of harm by the measures you’ve implemented to try and control it.”

Yet this, unfortunately, is the implicit view behind the Government’s policy, which makes it hard to rationally weigh the harms of lockdown measures against the reductions in risk from Covid. Indeed, Downing Street appears to still be following the alarming scenarios modelled by Warwick University, which show that any relaxation of social distancing measures before late 2021 will lead to another wave of deaths. But the authors of the Warwick models themselves acknowledge their assumption that vaccine efficacy applies equally to infection, mild and severe illness. However, they add, “if the vaccine has differential protection against the most severe disease this will impact our predictions for hospital admissions and deaths.”

And this is exactly what early data from Israel and elsewhere is indicating: vaccines may not prevent 100% of infections, but they do seem to prevent over 90% of hospitalisations and deaths. In effect, the Warwick assumptions about vaccine uptake, speed and effectiveness in preventing death, serious illness, and transmission are already being superseded by data. In Professor Woolhouse’s words: “Right now you should be looking at earlier unlocking, because the data is so good.”

This all sounds very positive. But while the R number is below one, it remains that the absolute case numbers are still comparable to those in spring last year. Official positive test results are over 10,000 per day, and the ONS estimates that over 700,000 people in the UK are currently infected, around 1% of the population.

The question now is: what is the end goal of the current social restrictions? Is it to keep hospitalisations within a level that the exhausted NHS can handle? Is it to keep deaths on a downward trend while restoring society to normality as fast as possible? Or is it to bring the rate of infection down to a level that could realistically be tracked, traced and isolated?

Only the Government can answer that question. It’s the responsibility of politicians, not scientists, to balance the risks of Covid against the social, economic and political impacts of the measures taken against it. Scientists themselves say so, again and again.

Risk is too often treated as a purely mathematical problem, but it has other dimensions too: psychological, social and political. There is no mathematical formula to tell any of us whether to take a chance on starting a business, proposing marriage, or riding a bicycle on city streets. We weigh up the possible outcomes and then commit to a course of action, in the knowledge that the future is uncertain and unknown. And in the same way, our leaders are forced to choose a course of action for the country as a whole.

Let us, by all means, be led by data. But data is a sextant, not a destination. What are we being led towards? What level of risk from Covid are we prepared to accept, and what are we prepared to sacrifice to reduce that risk? These questions are not statistical, but political.

Thanks to vaccines, the extra risks introduced to all our lives by Covid will soon be reduced to more familiar levels. Yet, having abandoned a rational approach to risk in favour of the view that “no Covid death is acceptable,” our politicians seem to be struggling to re-establish a grown up conversation about what we value as a society.

Zero-risk life is not an option. When Johnson finally reveals his “roadmap” to freedom, he would do well to start by explaining what kind of risk he is willing to take, and for what purpose.