Will vaccines protect against all international Covid-19 variants?

The UK’s vaccination progress could be undermined without strict border controls to guard against new strains. 

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We’re all sick of being stuck at home in lockdown, so let’s take a fun imaginary world tour. How about flying from the UK to South Africa, then Brazil? OK, it’s actually not so much fun. These locations, of course, are the origins of the various new coronavirus strains that are currently causing governments around the world such severe headaches. How scared should our tour make us? 

Before we answer that, let’s start with a more basic question: why have so many variants emerged around the same time? It partly speaks to our – largely the West’s – failure to control this virus. A greater number of infections means more opportunity for evolution – and therefore more new strains. In a sense, the new strains are our collective punishment for the terrible job that so many of our governments have done of containing the pandemic. There’s a reason that it’s unlikely (though not impossible) that we’ll be hearing about new strains of the virus from New Zealand, or Taiwan, or Vietnam: these are all countries that have effectively kept a lid on the virus’s spread.

That said, another explanation for why we’ve found a new variant in the UK is that we carry out a lot of viral genome sequencing. Chillingly, that means many other countries could have dangerous new strains that we don’t know about yet. Either way, the existence of new variants is one we have to face.

For each variant, we can ask three big questions. First, is it more contagious? Second, is it more deadly? Third, will the existing vaccines still work against it? For all three of the new variants discovered so far, the answer to the first question appears to be yes: they all seem to spread faster, and that’s why governments and scientists are worried. As for deadliness, the evidence is more uncertain, though a faster-spreading virus will likely lead to more deaths anyway.

What about our third question, about “vaccine escape”? Monday 26 January brought encouraging news from Moderna, the creator of one of the three vaccines that are currently licensed in the UK. The company released details of a study into whether its vaccine could still neutralise new strains of the virus, using blood samples from people and monkeys who’d been immunised. For the UK variant, the effect of the antibodies in the blood was the same (there’s a similar story for Pfizer). But for the South African strain, there was a six-fold lower degree of neutralisation.

That’s not as scary as it sounds. The Moderna vaccine is very effective against the original strain, so it starts from a high baseline. In an absolute sense, it’s only a little less effective. But it’s still concerning. Anything that reduces the effectiveness of the vaccine makes it harder for a country to reach herd immunity. Moderna is scrambling to produce a booster shot that could be used as a third dose to protect people from the South African strain. Pfizer will likely do the same. As far as I am aware, AstraZeneca is yet to release any similar research.

[See also: Stephen Bush on what Boris Johnson fails to understand about public health emergencies]

Throughout the pandemic there has been a strange tendency to think in absolutes. Do masks provide 100 per cent protection from Covid-19? No? Well, there’s no use in wearing one. Do lockdowns produce only positive effects? No? Well, they must be pointless. We can’t let such absolutist thinking – “The vaccine is less effective, so there’s probably no point in me having it” – affect our vaccine roll-out.

But the flurry of new variants should give us a strong push towards more serious pandemic control. You might have noticed that I didn’t mention the vaccines' responses to the Brazilian variant – that’s because we don’t have good data on it yet. While scientists are looking into it, we might find that yet another strain has arrived (on 23 January the possibility arose of a more contagious Californian variant). There is a constant risk of further mutation until we get a handle on the virus globally.

There’s nothing new or exciting to be prescribed here: we need to do the things that more successful countries have done to keep it from spreading further and from entering the country from abroad. That means vaccines, social distancing, test-trace-isolate, advice about fresh air, and the rest. But it also means stopping travel to and from the UK. At last, more than a year since the UK's first cases of coronavirus, the government has mandated hotel quarantine for incoming travellers from certain countries. We should consider taking this a step further and fully closing the border to essentially all travellers, as New Zealand has done.

Again, the absolutist thinking pops up: “Quarantines and border closures don’t stop all virus cases from getting through, so we shouldn’t bother with them.” This attitude was illustrated by a recent Daily Mail piece, which appears to argue against stronger border controls. It’s of course true that closing our border won’t be a panacea. Even in New Zealand, which has had a closed or extremely strict border for months, the odd case still manages to slip through.

But if border closures reduce the chances of seeding new, dangerous viral variants before our vaccination programme is anywhere near complete, even those of us who normally favour freer movement should support them. Our world tours may have to remain imaginary for a while longer, but holding back the surge of new variants gives us the prospect of getting over this pandemic all the sooner.

[See also: the NS international Covid tracker]

Stuart Ritchie is a psychologist at King’s College London and the author of Science Fictions: How Fraud, Bias, Negligence and Hype Undermine the Search for Truth

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