The Covid-19 virus, like many others, is unstable and mutates frequently. All vaccines target the “spike”: the sugary protein that allows it to bind to and enter our cells. The vaccines induce neutralising antibodies that block the spike and therefore infection. If the virus has mutations in its spike, the antibodies may be ineffective to varying degrees.
Three variants of concern have been reported since December 2020: B.1.1.7 in the UK, B1.351 in South Africa, both with 23 mutations, and the P1 variant in Brazil with 35 mutations. B.1.1.7 was traced back to in Kent in September 2020. Mutations increased its binding capacity and enhanced its transmissibility by 43 to 82 per cent. The variant played a key role in the second wave in the UK and has reached 93 countries.
One study suggests this variant increases the death rate by 64 per cent from 2.5 to 4.1 per 1,000 detected cases. A larger analysis of B.1.1.7 in the community suggests deaths are 55 per cent higher after adjustment for age, sex, ethnicity, deprivation and care home residence. This may counteract many of the benefits of dexamethasone and other improved treatments.
Does the UK variant also escape vaccine-induced antibodies? To a limited degree it can. Lab studies show it reduces the strength of the antibody response by about 20 per cent overall, but this is too little to affect the overall protective efficacy of the vaccines. But neutralising antibodies in people over the age of 80 were reduced to a much greater extent so this age group needs careful monitoring.
The South African variant is cause for greater concern. It carries the E484K mutation, which is thought to play a role in evading immunity, as does the Brazilian variant and a small number of UK ones. Preliminary studies show that the Oxford/AstraZeneca vaccine induces much lower protective antibodies to this variant, and a small trial in South Africa of 2,026 participants aged 18 to 65 showed vaccine efficacy against the variant was just 10 per cent. We don’t yet know whether the vaccine still protects against severe disease (much larger studies are needed) but South Africa has paused the roll-out of the AstraZeneca vaccine and is using the Johnson & Johnson jab.
Not all the science is gloomy, though. Vaccines induce a wide range of neutralising antibodies that can protect in ways other than blocking the spike. The number of spike mutations is finite, which limits the ability of the virus to escape. Immunity is afforded by T cells as well as antibodies. And modern science can respond quickly to mutations with redesigned vaccines within months, as it does for influenza.
But while our vaccines are a brilliant necessity, they are not always sufficient for control. Viral spread depends upon three key factors: the number of contacts, the transmissibility of the virus, and the period of infection. This last factor can be successfully controlled with effective contact-tracing and isolation. Modelling shows this is highly effective when case rates fall, and a recent field study in Germany showed quarantine of secondary contacts outside infected households reduced onward spread by 52 per cent. Lockdowns are a more inefficient and economically damaging way to control the spread. Countries that implemented test, trace and isolate programmes at speed (South Korea, Singapore, Taiwan, Vietnam, China, Thailand, Iceland) avoided whole national lockdowns, with a much smaller effect on GDP and far lower death rates.
On 9 March Chris Whitty, England’s chief medical officer, told MPs that a further surge is inevitable. Patrick Vallance, the chief scientific adviser, emphasised that tracing and isolation would be critical as case rates fell. We cannot eradicate the virus from the earth, so a zero-Covid strategy to eliminate spread within countries is inherently unstable.
There will be outbreaks that need rapid suppression. We have never managed to meet the target to turn around all tests in face-to-face settings in 24 hours. Test results are not linked with primary care, nor with local public health teams, so GPs are in the dark about their patients.
Local contact tracing has consistently outperformed England’s ineffective and exorbitantly expensive Test and Trace programme, which is based on outsourced call centres, testing outside the NHS, and a hard-to-access financial support scheme for those asked to isolate. It is deeply troubling that the government persists with outsourcing. When fighting a war against the virus we need an army of contact tracers on the ground: around one worker per 1,000-1,500 people. In Wuhan they used one per 1,200 in teams of five. A northern district public-health director told me he still has only 19 tracers (not the 100 he needs), funded using his routine budgets, with nothing from the national programme’s projected £37bn budget.
The Public Accounts Committee found no clear evidence that Test and Trace had reduced coronavirus infections. It is deeply troubling that the government persists in allocating an “unimaginable sum” to a system Nicholas MacPherson, a former Treasury permanent secretary, said “wins the prize for the most wasteful and inept public spending programme of all time”.
Above all, we want those infected and their contacts to isolate as quickly as possible, but the system acts as a deterrent. In Liverpool, three-quarters of those who applied for the one-off isolation payment of £500 were rejected. As England lifts lockdown restrictions, a further failure to control local spread will only increase the risk of viral mutations causing “vaccine escape” and of a third wave hitting the NHS and affecting younger people.