UK coronavirus variant spreading rapidly around the world likely emerged from a single infection – ABC News

Like every other virus before it, SARS-CoV-2 has only one goal: to survive.

The longer an outbreak rages, the more people contract but survive the infection, leaving the virus with a dwindling number of vulnerable bodies to infect.

Its best chance of longevity is to evolve.

In doing so, the virus has to strike the right balance. If it becomes too deadly, it risks killing its host before finding another.

So the trick is to become more transmissible, but less deadly, vastly increasing the virus's chances to spread and persist.

We may never know exactly how the UK variant came to be, but it seems likely that about six months into the pandemic, the virus found the perfect body in which to perform this transformation.

From this single infection, a new form of coronavirus emerged, and it's carved a deadly path across the world.

As the end of 2020 approached, UK health advisers became increasingly worried about a second wave gripping the country.

In September, they noticed that the coronavirus was spreading at a faster rate. And with winter on the way, cases were only expected to increase.

As experts discussed the need for more action, the government moved to a higher alert level.

"This country now faces a tipping point in its response and it is vital everybody plays their part now to stop the spread of the virus and protect lives," British Health Secretary Matt Hancock warned at the time.

But already a new variant had emerged. In the space of a few months, it would take over the country.

Referred to by an innocuous string of letters and numbers, VUI-202012/01 or variant B117, it was first identified in the county of Kent on September 20.

Its existence wasn't confirmed by the UK government until December 14. By then, the strain was already spreading with dangerous efficiency, causing a huge spike in cases in south-east England and London.

At the time, UK officials warned it could be 70 per cent more transmissible. Further studies have suggested it could be anywhere from 36 to 71 per cent more infectious than the original Wuhan virus.

Either way, the variant had changed the course of the pandemic in the UK.

And just a month later, its tentacles were stretching around the globe.

It's now in 80 countries, including Australia, and triggered swift lockdowns in Queensland, Victoria and WA.

The exact circumstances of the UK variant's birth may forever remain a mystery.

But most scientists agree it probably evolved in just one person whose infected body was plagued by the virus for a longer time than the average 14-day incubation period.

That patient may have had a long-term, chronic COVID-19 infection, according to University of Queensland virologist Kirsty Short.

"Perhaps [it was] an individual who's immunocompromised," she said.

When influenza infects a person with a chronic medical condition, their immune system takes longer to fight off the virus.

"They can be infected with influenza for months [and are] actually more likely to generate these viral variants than an individual who has a short and acute infection," Dr Short said.

"So, let's imagine that the virus mutates once every time it replicates. If you have an individual in whom the virus has replicated 500 times, there's going to be more mutations than in the individual in whom the virus is replicated five times."

The one silver lining of this pandemic that scientists had identified early on was that coronaviruses mutate far slower than influenza or HIV.

Previous studies have found SARS-CoV-2 usually shows no more than a few mutations, and these can build at a relatively consistent rate over time.

One estimate suggested circulating SARS-CoV-2 lineages accumulate at a rate of about one to two mutations per month.

The UK variant, however, is different.

It has 23 mutations compared with the original virus discovered in Wuhan, 17 of which have appeared since the virus diverged from its most recent version.

Damian Purcell was at his Melbourne lab in late 2020 when he came across a "big surprise" in an online database of global SARS-CoV-2 genome sequences.

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The head of the molecular virology laboratory at The Peter Doherty Institute for Infection and Immunity in Melbourne was looking at the details of the new UK variant.

"We were really surprised, actually, we looked at this and said, 'Wow, look, look how many mutations this virus has got, and look where they are, there's so many in the spike protein'."

A spike protein is found on the outside of the virus and is what fits to the receptors inside our bodies and allows the virus to infect us.

It essentially acts like a key unlocking our body to the coronavirus infection.

"That's the protein that we're most interested in, in terms of understanding the efficacy of vaccines that we're involved in testing," Professor Purcell said.

The UK variant's strange features swiftly earned it a nickname.

"We actually initially called this virus Frankenstein," Professor Purcell said.

"Essentially it was made up of many different parts, it has mutations that we've seen in individual viruses here and there, but they're all popping up in the one virus. So it was a big surprise."

Countries in the grip of soaring infections have a higher chance of producing these variants as the virus seeks out more hosts.

But there is a possibility that the UK strain may have started elsewhere, entering the country through an unsuspecting overseas traveller.

Professor Purcell said the discovery of the strain may have been made possible by the fact the UK studies more genome sequences of positive COVID cases than most other countries.

"So the UK may have seen it because they were looking for it. And if you don't look, you don't find it," he said.

But while they may have had the tools to identify new strains, UK authorities were still playing catch-up as this seemingly fast-spreading variant raged around the country.

By November 2020, around a quarter of cases in London were identified as having the new variant. By mid-December, it had reached 60 per cent.

The UK health system was nearing breaking point and public health experts warned of a deadly winter like no other.

With few options left, Prime Minister Boris Johnson soon delivered the Christmas message no-one wanted to hear.

"It is with a very heavy heart I must tell you we cannot continue with Christmas as planned," Mr Johnson said on December 19.

"I sincerely believe there is no alternative open to me."

The UK strain is not the first time a variant of SARS-CoV-2 has emerged. There could be thousands of different versions of the virus currently circulating the world.

More often than not, a variant doesn't have much impact on an outbreak, and many disappear.

But now and then a virus has a breakthrough. A new strain finds a way to infect more hosts and in rare cases, becomes the dominant force in a pandemic.

While more recently the focus has been on the UK variant, other experts are closely monitoring a potential new strain identified in the US state of California.

But if there's one mutation above all others that scares scientists, it's one called E484K.

"We give many of the virus strains little names, pet names in the lab. There's another one mutation associated with B1.351, which is also known as a South African virus," Professor Purcell said.

"It's got this mutation known as E484K. That's been dubbed 'Eek', because of its potential to escape antibody immunity."

E484K can make it harder for the immune system to recognise and fight the virus, even if the body supposedly learned how to fight the virus from a vaccine.

What worries experts is how this could impact the rollout of COVID-19 vaccines, which may not be as effective against emerging variants.

Earlier this month, South Africa paused its rollout of the AstraZeneca COVID-19 vaccine after a small study suggested it offered minimal protection against mild and moderate infection from its coronavirus strain.

It sent the Oxford team scrambling for a fix. But the reality is these kinds of setbacks are to be expected in vaccine development, especially as more strains surface.

The perfect COVID-19 vaccine may never exist, according to Larisa Labzin from the Institute for Molecular Bioscience at the University of Queensland.

"When I say that, I mean one that would essentially help us eradicate the virus altogether," she said.

"It would stop transmission, it would work against all potential variants, it would mean that we could go back to pre-COVID times immediately."

But the existing vaccines on the market may be able to prevent severe cases of COVID-19 associated with the South African variant.

"I think the evidence is still that the Oxford-AstraZeneca vaccine is going to be able to do that. And we're going to be able to reach more people more quickly with that," Dr Labzin said.

"It can be just a stopgap it'll give us the time to manufacture potentially those other vaccines that are more effective.

"And we'll be able to update the vaccines to reflect the new variants as well."

The emergence of new variants shows us that the threat posed by the coronavirus isn't going away, even with vaccines rolling out in some countries.

Instead, following public health advice wearing masks, maintaining social distancing, hand washing and avoiding mass gatherings remains more important than ever.

"These strains have got a small leg-up. They're not Superman compared to the original," Professor Purcell said.

"They were a little bit more aggressive, more successful, but those measures still work equally well against them."

Still, he believes our safest way out of the crisis still rests on the worldwide rollout of vaccines.

"[It's] going to be crucial in squashing the opportunity for the virus to spit out these freaks, these unlucky mutations that are successful and break vaccine immunity," he said.

"So the more people we can vaccinate and the sooner we can vaccinate, the better."

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UK coronavirus variant spreading rapidly around the world likely emerged from a single infection - ABC News