Philip Thomas

Barely six weeks after it was first discovered in Britain, the Omicron variant has changed everything. Cases have soared far beyond records made in the first wave. Hospital admissions are surging and pupils are once again wearing masks in school. Modellers have produced terrifying figures — up to 25,000 hospitalisations a day, more than five times the last peak. It looks like a Covid groundhog day, a doom loop we seem unable to escape. Last summer, just before the end of lockdown, I wrote in this magazine about a ‘third wave’ of infections which could be just as big as the first. But my model also pointed to something else: that we could ride out this wave without the health service being overwhelmed and without the need for further restrictions.

A few weeks ago, as the government was preparing for a great reopening on 21 June, I wrote a cover story for The Spectator with some bad news: a third wave was coming, I argued, and it could be even bigger than the second. It jarred with the mood. Covid cases were falling and a great many people desperately wanted this to be the end of it. My model, the Bristol University PCCF (Predictor Corrector Coronavirus Filter), showed otherwise: the biggest wave could be yet to come. But with a vital difference: hospitalisations and deaths would be much lower than at the beginning of the year when we were largely unvaccinated. All of that has come to pass, with one exception.

Lockdowns cannot kill off a virus — they just delay the spread. There was always going to be a new wave of infections as Boris Johnson phased out restrictions. The question was how big it would be and how much protection the vaccines would provide. Chris Whitty, the chief medical officer, summed up the case for optimism a few months ago, saying that any ‘new surges will meet a wall of vaccinated people’. His theory is now being tested: the fast-spreading Indian (Delta) variant is making its way through the most vaccinated country in Europe. What to do? And how worried should we be? Since the pandemic began, I have been trying to answer such questions. I’m a professor of risk management at the University of Bristol, not an epidemiologist.

Professor Neil Ferguson struck an unusually optimistic tone this week. With just one Covid death reported on Monday, and infection levels at an eight-month low in the UK, the architect of the original lockdown said: ‘The data is very encouraging and very much in line with what we expected.’ The first half of that statement is certainly true; the second half much less so. As an unofficial member of the government’s Scientific Advisory Group for Emergencies (he resigned in an official capacity after breaking lockdown rules) Prof Ferguson has been responsible for much of the pessimistic modelling during the pandemic.

With every passing day, more Covid immunity is being gained as hundreds of thousands receive the vaccine. Of course, vaccines take time to mature in the body and offer protection, but with roughly a quarter of the population having now received their first inoculation, our approach to dealing with the virus will inevitably need to shift. The big question is how vaccination has changed the equation for how quickly society can be reopened. Modelling from the PCCF project at Bristol University, on cautious assumptions, suggests that the pace of the vaccine rollout would allow significant reopening with herd immunity achieved in July. First, let’s say how much vaccine immunity has been induced by the vaccine.

England's population immunity to Coronavirus now stands at almost 39 per cent — a rise of 25 per cent since Christmas. The effects of the vaccination campaign are beginning to show. This is the latest finding of the PCCF model developed at Bristol University, and its results offer important insights into how much progress is being made. Immunity can take four forms, not all of which are officially recorded: Immunity after infection, with antibodies: This can be sampled via antibody tests and covers between 15 and 16 per cent of the population as of mid-January, according to the latest ONS report.

It seems that Boris Johnson will not begin to think about lifting lockdown restrictions until we have clear evidence that the latest wave of the virus has almost been defeated. So it was not exactly good news yesterday from Imperial College’s React Covid survey, which suggested that even though we are in lockdown, the R number is still almost at 1 in Britain – meaning the epidemic is barely shrinking. As part of React’s ‘viral opinion poll’ swabs were taken from over 160,000 people in England between 6 and 22 January.

There is a long-standing belief that herd immunity can only be achieved once between 60 to 80 per cent of the population is immune. This notion, however, does not take into account the fact that immunity can be achieved at a lower figure if social distancing measures are factored in. The herd immunity threshold, in fact, is not fixed — it depends on the amount of social distancing we are doing, and, specifically, on what epidemiologists call the 'basic reproduction number', known as the R0-value. A PCCF (standing for 'predictor-corrector coronavirus filter') measurement tool is under development at the University of Bristol. It has successfully projected the trajectory of the virus, making use of models to help it do so.

How big is the job of vaccination? The aim is herd immunity, to protect enough people so that the virus starts to run out of people to infect and rates fall. This is expected to happen when between 60 to 80 per cent of the population is protected, so quite a job for the NHS. Until this is achieved, ministers seek to use lockdown as a tool to keep the R below 1. This means the cycle of lockdown and release could be with us for some time, especially in light of the new ‘mutant’ strain of the virus. But are ministers seeing the whole picture? As a professor of risk management, my coronavirus modelling has shown a large gap in the data on coronavirus cases between the government’s dashboard figures and the ONS weekly surveillance data.

At times, the argument about lockdown has been described as a choice between saving lives or saving money. But this is a false equivalence. A weak economy leads to weakened citizens: it means less tax revenue, less money for the NHS, and poorer families — wealth and health are all too-closely linked. Just look at the difference in height between Koreans, depending on which side of the 38th parallel their grandparents happened to be caught on. It’s easy to measure money, but it’s far harder to measure the indirect results of a richer or poorer economy. It’s also hard to work out how much money you should spend to save a life. Ban cars, and you’ll end road deaths. But you’d also hit the economy. So a balance has to be struck somewhere.

In four decades working as an engineer and scientist, I have rarely known a more polarised time within the scientific field. The marketplace of ideas is depressingly split down the middle: you are either for herd immunity in the shortest possible time or for a full lockdown. There is, however, a third way: a method that will allow the coronavirus to slowly spread within the population without causing a very high death toll and overwhelming the NHS – while, at the same time, protecting the economic and social wellbeing of the country. How can this third way be achieved?