Just when we thought there was cause for optimism in Covid-19 vaccines, we have hit a wall. Christmas is off and we may all be locked up for months longer. In fact, the vaccines, even once safe and effective, had little chance of infecting the virus this winter. It has never been possible to produce, distribute and appeal to all those in need in such a short time.
However, a move towards a kind of regularity before spring seemed possible. The UK government’s decision to introduce phase four lock-in restrictions across London and much of the south-east, and the travel bans imposed by other countries on UK citizens have created chaos. What prompted such an action?
The answer is a new version of Sars-CoV-2, which is thought to have developed an infection. Retrospective analysis followed the first known case of the variant, entitled “VUI – 202012/01 ”(first Change under Scrutiny in December 2020), to Kent on 20 September. By mid-November, around a quarter of cases in London were caused by the new variant and by mid-December nearly two-thirds. Modeling the relative probability level of the new variant has shown that it could be 70 percent more mobile than earlier versions of the virus, although this has not yet been directly confirmed. One alarming suggestion, from researchers at Imperial College London, suggests that children may be more vulnerable to the new variant. If this is correct, the ramifications are bad both for further spread and for potential school closures.
Apparently old versions of the virus were moved by this new one, resulting in more spread. But evidence has yet to come that it can cause more serious disease, and a higher mortality rate. In fact, viruses often become more aggressive but more contagious as this increases their overall transmission capacity. However, a faster-reproducing virus reaches higher numbers more quickly and may be difficult for some humans, which would normally elicit an appropriate immune response, if the immune response is their last.
Disease anxiety data should already be available. The national consortium of laboratories that follow viral strains constructed in the detection program can identify spreads. If the clinical picture also indicates an increase in hospitals and deaths where the new variant is most common, we can find the worst. Reducing spread looks sensible. But the virus has been circulating for at least three months already, so there is little chance of stopping its spread now.
Will the vaccine treat the emergency? Probably, and the standard vaccines will work against this new variant. But we have to be careful. The movement in the new snout that attracts the most attention is inside the spike protein (S). It is the S protein that allows the virus to bind to receptors (specifically the ACE2 receptor) on our cells before entering and clearing the cell’s apparatus to reproduce many new copies of itself and to create. The Sars-CoV-2 coronavirus has been in steady state from first sight. Such a mutation is normal. It is the basis of the evolution of all forms of life. Changes occur randomly as errors creep in while the genome is replicated. Many destructive mutations and so are quickly lost. Others are neutral, not strengthening or reducing viral fitness. Rarely, however, can viral fitness change progress. When these happen, as in the novel version, the virus spreads more easily.
[See also: Stephen Bush on why the quarantine of the UK is about coronavirus, not Brexit]
The viral genome encodes the proteins that make up the virus itself and mutations lead to changes in that structure. The proteins themselves are made up of layers of small chemicals called amino acids. One of the amino acid changes in the new virus sits in the very part of the protein that binds to ACE2, allowing it to bind more tightly. Other mutations occur in the S protein as well. It is the original S protein, the one found in the ancestral virus from Wuhan, which contains all currently approved vaccines, and most in development.
There is little cause for fear because antibodies and T-cell responses, the two branches of immune defense, hit several sites throughout the S protein, so the new variant is still recognized by immunosuppressants in humans vaccine. However, as the vaccine is more widely used, the virus will be under increasing pressure as it enters hosts equipped with destructive antibodies. Only viruses with mutations allow them to avoid such antibodies. As the remaining ones expand, new mutations will appear, each new S protein resembling the original smaller version.
These changes are possible to get vaccinated, although it is not yet clear. The S protein must maintain the ability to bind to ACE2 limiting the number of possible sockets. Moreover, the remarkable scientific advances achieved through the pandemic mean that, in principle, we can change the S proteins added to the vaccine almost as quickly ‘ in which they appear.
The flu virus has a much greater ability to circulate around Covid-19 which is why we make new versions of the flu vaccine every year. It is very simple to change the range of vaccines we have now created, although a measure of safety and efficacy will be required each time.
In short, the new variant, with increased infectivity, is a cause for alarm. If it seems to be stronger too, it gets worse. If this is the first step towards a series of viruses moving away from the structure of those used in the generation of vaccines, this is even worse.
We need to perform a test to find the viruses and the sequence to detect a mutation problem. But we also need to redouble our efforts in other areas. Drugs that target parts of the virus outside of S protein, for example, are needed more urgently than ever. A clear and robust test and detection system, backed by emergency loneliness, is as essential as ever.
The UK has been at the forefront of scientific efforts to combat coronavirus. Ultimately, whether or not countries have successfully dealt with Covid-19 has depended on political intervention. – where Britain is not so good.
[See also: Harry Lambert on how Covid-19 vaccines could reduce the UK’s death rate]