The headlines referred to the Health Secretary Matt Hancock’s revelation in the House of Commons on Monday that a mutated strain of Sars-CoV-2 had been identified in the south east of England, and that it is spreading faster than previous strains.
Hancock didn’t give many details – in fact, most immunologists and virologists were blindsided, scrambling to work out which particular strain he was referring to. Only later that evening did scientists at Ravindra Gupta’s lab in Cambridge post the preprint paper, which described the strain, online. The Covid Genomics UK Consortium also confirmed it had been tracking this new strain.
The word “mutant” does seem rather alarming at first glance, but new variants of the coronavirus are to be expected, since the virus (in common with every population of living things) is constantly evolving. Unlike humans, this virus doesn’t use DNA for its genome. DNA has a good built-in mechanism for repairing mutations, allowing very few to pass on to the next generation. The coronavirus uses RNA, which is much more unstable and prone to mistakes. These errors during its replication give rise to new viral subtypes that, if they happen to be the more transmissible ones, can quickly become widespread (by the same token, some strains of the virus have appeared and then gone extinct due to factors such as the lockdown).
Keeping up with all these new strains is a major task of microbiology. Luckily, coronaviruses have features that make them evolve more slowly than other RNA viruses which have really shoddy error-checking mechanisms, such as influenza. Because of the superfast evolution of the flu, we are required to come up with new vaccines year after year, continuously running, Red Queen-style, to stay in the same place. Excitingly, a new advance towards a so-called universal flu vaccine, which might be useful against all flu strains, was published earlier this month, but it’s still at early stages.
What of our Covid-19 vaccines? Have they already been superseded, like last year’s flu vaccine? Most immunologists who have commented on the new coronavirus strain don’t seem too worried about it getting around our new vaccines. The specific difference that characterises this strain – a change to the sequence of its spike gene, which helps make the protein it uses to enter cells – is very unlikely to render the vaccine useless, since the vaccine triggers the body to create antibodies for a range of spike variations.
And it’s not as if the vaccine has only been shown to work against one strain of Sars-CoV-2. As noted by the biologist Ewan Birney, the vaccine trials weren’t happening in a hermetically sealed environment involving on one kind of virus: they happened in the real world, with all sorts of mutant strains buzzing around in the summer and the autumn. Even then, they were incredibly effective at preventing disease.
So why might Hancock have made this announcement? Although he did add caveats – the most important being that, even though this strain might spread more efficiently, there’s no evidence it causes more severe symptoms – it is unusual for a scientific finding to be announced in this way, especially before the data are released publicly.
Perhaps the intention was to make us realise the ongoing risk, and to continue taking care – taking more care – not to spread the disease. The authors of the paper that described the new strain concluded the most important thing to do, apart from carefully tracking the new virus subtype, is to redouble social distancing, mask wearing and case isolating.
But if an attempt to reduce transmission was the purpose of the announcement, it sits uneasily with what’s about to happen. England is about to replace the tier system with much looser restrictions over the Christmas period from 23-27 December. Having people – many of whom won’t have self-isolated, or won’t be able to isolate on their journeys – crisscrossing the country to visit often elderly relatives is a catastrophe waiting to happen. And that was the case before we knew about this new viral strain, which will be much harder to study and trace if we help it to spread.
Was Hancock trying to have things both ways? That is, allowing people to see their families to avoid bad “Christmas is cancelled” PR, while putting the fear of CoV into them so they don’t mix too much? If so, it seems amazingly irresponsible. On the other hand, perhaps Hancock agrees that the Christmas amnesty is a terrible idea, and is trying to push his cabinet colleagues to revise it.
The discovery of this new strain reminds us of the many ways in which viruses exist out of our control. But we are in control of our social distancing policy. Next Christmas, we might look back on how we eased up our efforts to combat coronavirus for no rational reason, and see it as a tragic folly.