How can we stop the spread of the new Covid-19 variant from South Africa?

What’s worse than one new strain of highly infectious COVID-19?... It’s like a joke from the worst Christmas cracker ever.

But tonight we learned that yet another variant of SARS-CoV-2 has shown up in the UK  — this time imported from South Africa.  

And this one, the government warns, may be more infectious than the new one we’re already trying to get under control.

The South Africa strain was already on our public health radar. It emerged in the Eastern Cape around the same time the new UK variant appeared in Kent. Partly because of that, Public Health England spotted it pretty quickly.

Yesterday, two cases of the South Africa strain were detected in the UK, both linked to another person who had travelled from South Africa. We don’t yet know if the cases are a cluster (linked to the same traveller) or not. Both are now in isolation.

The South Africa strain shares one mutation with the UK strain called 501Y: a potentially crucial one on the bit of the virus’ “receptor binding domain” that might help it grab onto our cells and infect them.

But it has several other potentially important mutations that are completely different from the ones the UK strain has evolved.

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However, like the UK strain the latest evidence from South Africa suggests that it doesn’t cause more severe disease than its predecessors, and while it's possible pre-existing COVID antibodies or vaccines may be influenced by the new mutations, there's no strong evidence yet — and experiments to answer those questions are underway.

The virus spread extremely rapidly in the Eastern and Western Cape outbreaks in South Africa and is now the dominant strain there.

This is a very similar picture to how the new UK strain spread across the southeast and London. However, there is some suggestion the South Africa strain may have spread even more quickly.

Fortunately for the UK, we had already implemented tier 4 restrictions before the South African strain arrived — so it won’t enjoy the same freedoms here as it initially did in South Africa.

The hope will be that its arrival can be contained, reducing the challenge of dealing with not one, but two new strains of COVID-19.

What we are undoubtedly seeing now is the SARS-CoV-2 virus evolve before our very eyes. In areas where it has had the opportunity to infect many, many hosts, we are seeing it adapt to them and their immune systems.

These variants have been detected in the UK and South Africa because they share two things in common.

Both countries have world-class surveillance for viruses as they evolve and both failed to contain the virus from infecting large numbers of people.

That leaves the question open as to how many other new strains of COVID-19 may be emerging in other countries with poor genetic surveillance for viruses.

It also serves to remind us that the best way to stop SARS-CoV-2 from mutating even more, is to do everything we can to stop it spreading.