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. It’s a gap that could be explained by a basic fact: that a large chunk of the population, perhaps as many as 30 per cent of us, already have a significant degree of immunity to the virus.
Let me explain. I’d like to look at two types of immunity; the first type is acquired by having caught and fought off the virus – and this is about 17 per cent, 6 per cent from the first wave, as measured by the ONS in antibody surveys, and roughly double that amount in the lower but broader second wave, as deduced by modelling. The second is T-cell immunity which studies show can exist in people who have never been exposed to Covid-19.
Last month, Public Health England’s EDSAB-HOME study estimated that 12.9 per cent (with a confidence interval likely between 11.5 and 14.3 per cent) of the English population had T-cell levels and consequent protection – despite never having contracted Covid-19. The conclusion of the study, which is awaiting peer review, was that ‘People with higher levels of T cell recognising SARS-CoV-2 are protected from Covid-19.’