What the new strain means for our fight against Covid

21 December 2020

11:16 PM

21 December 2020

11:16 PM

‘What’s going on in Swale?’, asked a health journalist who I often speak to. This was back in November. I responded that I didn’t know where Swale is, let alone what its problem was, although I guessed it was most likely something to do with Covid-19. But now, we’re all looking at places like Swale — and much of Kent — and wondering what’s going on.

Back in the summer, the UK government would put countries on the quarantine list when their infections hit 20 per 100,000 residents. In Swale, at the last count, it was 2,600 per 100,000 residents. Kent’s MPs were furious that their constituencies were placed in Tier 3 when the November lockdown ended — but now, the area is one of the world’s Covid hotspots.

Whatever is causing this mutation, it appears to be substantial. Analysis by Nervtag, the government committee which monitors respiratory tract infections, suggests that the new strain is growing 71 per cent faster than other variants. That it is pushing the R number up by something in the region of 0.39–0.93.

People who are infected with the new strain, on average, seem to have a viral load three times greater than people infected with other versions of Covid-19. A common misconception is that ‘viral load’ refers to the amount of virus which infects a person. It does not. Viral load is the amount of virus produced within an infected individual. Consequently, you would expect more virus to be emitted by an individual during the period in which they are infected. This could explain, at least in part, why this new variant is spreading between people so much more frequently. We can expect to hear a great deal more about this issue in the coming days and weeks.

One curious aspect of all this, which has not garnered much coverage, is the report from UK researchers that treatment of patients with convalescent sera (antibodies extracted from people who have recovered from Covid-19) could be providing an opportunity for viruses carrying new versions of the spike protein to outcompete those with the original version. Antibodies reactive to that original spike protein may provide an opportunity for novel versions to thrive — while killing off the virus with the ‘old’ spike protein, it may allow the new kids on the block to take over. In other words, the very treatments being used to treat Covid patients could be helping some new mutants to bloom.

While we know that in the UK, the virus appears to have originated in Kent, what is not clear is whether this is a wholly British phenomenon or whether it came originally from abroad. There are reports in the Italian press suggesting it might have come from Spain and was taken back to the UK by holidaymakers. Professor Andrea Crisanti from the University of Padua is quoted saying ‘England is the country where the most sequencing is done in the world and unfortunately the more you search the more you find it.’ There can be much criticism levelled at Britain for our handling of the pandemic, but we have had world-leading surveillance. This is not always the case elsewhere. Indeed, it is very possible that today, as we are treated like the new Wuhan, the pariah of Europe and much of the world, this new strain is already totally saturated in other countries. What’s more, it could very well have originated elsewhere.

What does this all mean for the vaccine or post-infection immunity? The jury is still out, but there have been worrying suggestions of reinfection. Nervtag has reported four ‘probable’ re-infections out of 915 cases of the new strain. This raises the prospect that those who caught the first strain may be vulnerable to the new strain — but Nervtag says ‘further work is needed’.

How could the virus potentially outfox the vaccines? Let me explain. The vaccines target the virus’s spike protein, which is essential for an infection to become established, but they can do that in different ways. What vaccines do is mimic infection, prompting the body’s immune system to produce antibodies. These antibodies will either instruct white blood cells to destroy the virus or they will latch onto the spike protein, blunting its ability to attach onto target cells. If the antibodies just tag the virus for destruction by white blood cells, there probably won’t be much of an effect — the spike protein is similar enough that antibodies can still tag the virus for destruction. But if the antibodies work, at least in part, by inhibiting the spike protein then we may have a problem. If the lock no longer fits the key — that is, if the spike protein has changed its shape to the point where the antibodies can no longer properly attach and disarm the virus — then the vaccine may well be less effective. This is where the new strain differs from previous variants.

While mutations are unlikely to render a vaccine useless, we must be aware that they could blunt their effectiveness and stop them from being the silver bullet that some people expect them to be.

Matt Hancock’s announcement last Tuesday in the House of Commons of a new, more infective variant was met with scepticism and dismissal from some scientists — in spite of evidence that this coronavirus can change spontaneously to become more virulent and transmissible in mice, according to Chinese researchers. Scientists will always rightly doubt new claims until they are backed up with data. It was, therefore, rather unwise for the Health Secretary to have dropped such information without hard evidence.

That said, the government cannot win here: if it holds things back while its scientists investigate, it is accused of hiding things. If it flags up possibilities where there is still uncertainty, it is met with criticism. Grown-up conversations, after all, require both parties to be grown-ups.

Throughout this whole sorry episode, there has been a tendency to think that things will just improve, that the virus isn’t that bad, or that the virus would just disappear. Coronavirus has shown us repeatedly that it will catch us off guard if we are ruled by wishful thinking.

Until the vaccines are properly scaled up and shown to work with this new strain, our behaviour must continue to change and our interpersonal contacts kept to a minimum. The government had no real alternative option but to impose tighter restrictions on many of our lives, to do anything less would have been grossly negligent.

There is a glint of light at the end of the tunnel with the vaccine trial data, but the road ahead will likely be rocky, filled with more twists and turns. The advent of this new, more infectious strain at the worst time of year for respiratory tract infections is very unlikely to be the last nasty surprise to come our way.

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