21.10.2021

Covid South African variant and its spread in the UK

The infections were picked up in eight different English postcodes, suggesting that the new variant may now be spreading in different pockets of the population – rather than being imported via travellers to Britain.

It is concerning news made even more worrying by the fact that these individuals had no travel links to the country, and nor did their close contacts.

What are the facts?

A total of 105 cases linked to the South African variant, known as 501Y.V2, have been identified in the UK since 22 December – but all of those had links to travel.

On Monday, health officials said that 11 new community-based infections had been identified within the last week.

Experts believe the cases may have second or third generation connections to South Africa but detailed investigations have not confirmed this.

The infections have been detected in the following eight areas: Hanwell, Tottenham and Mitcham in London; Walsall, West Midlands; Broxbourne, Hertfordshire; Maidstone, Kent; Woking, Surrey; and Southport, Merseyside.

Single cases were detected in all areas except Woking and Tottenham, where infections were linked to two different households.

Of the 11 people identified, all have been told to self-isolate, along with their close contacts.

What do we know about the new variant?

501Y.V2 is thought to be as transmissible as the variant that was first identified in Kent.

Initially detected in South African swab samples from October 2020, it has obtained a series of notable mutations in its spike protein – the part of the virus responsible for binding and entering human cells.

This includes the E484K mutation, which changes the shape of the protein in a way that makes it less recognisable to the body’s immune system.

As a result, the South African variant is capable of evading parts of the immune response triggered by vaccination or natural infection.

The vaccines that have been approved to date are still capable of offering protection against 501Y.V2, but various analysis and trial studies have suggested they may not be as effective.

Still, there are high hopes that the current generation of vaccines will protect against severe illness and hospitalisation from 501Y.V2, while experts advising the UK government do not believe the jabs will need to be tweaked to deal with the variant.

How widespread is 501Y.V2 in the UK?

Community spread of 501Y.V2 is to be expected on account of its transmissibility and stealth-like nature in passing from one person to another before the onset of symptoms.

Dr Julian Tang, a virologist at the University of Leicester, said the spread of the variant among people with no travel history “is not surprising and was somewhat inevitable once we heard about the identification of some imported cases a few weeks ago in the UK.”

Although only 11 community-based cases have been detected, it’s highly probable there are many more infections circulating undetected in each of the different areas identified by health authorities.

“So for every case we identify, there may be many others infected depending on the amount of pre-symptomatic/asymptomatic contacts that have occurred,” says Dr Tang.

Scientists sequence up to 10 per cent of all positive cases as part of the UK’s genomics surveillance programme. This means there is “a high probability that further local cases are in circulation, making it more difficult that the spread of the variant can be contained,” says Rowland Kao, a professor of veterinary epidemiology at the University of Edinburgh.

What about the vaccines?

For now, the current lockdown measures in place will prevent 501Y.V2 from spreading like wildfire, as was the case with the British variant before Christmas, but its presence within the community is of concern for when the UK opens up again.

Pockets of the population will remain vulnerable to the virus, having not been previously infected or vaccinated, and may allow 501Y.V2 to continue circulating.

Given its high transmissibility, the South African variant could fuel a third wave of infections and hospitalisations that once again overwhelms the NHS – especially if restrictions are lifted too quickly and people begin mixing in public spaces.

Of course, the UK’s cause is helped by the impressive roll out of the Covid-19 vaccines, with figures showing that more than 9 million people have now received a first dose.

Trial studies have meanwhile shown that vaccines produced by Johnson & Johnson, Moderna and Novavax still offer protection against 501Y.V2 – roughly 60 per cent in the case of the latter – but are not as effective as they were against the original form of the virus.

Even so, both Johnson & Johnson and Novavax have reported that none of the people who received a vaccine in their South African trials died of Covid-19.

Indeed, even with lower efficacy rates, there’s quiet optimism that all five of the vaccines to have released positive trial results will either prevent or reduce hospitalisations and deaths among those exposed to 501Y.V2.

If further analysis and data confirms this, that’s a big win for the public and will ensure that life can start to gradually return to some degree of normality later this year – though the ability of 501Y.V2 to reinfect people (but not necessarily cause illness) will remain a threat that authorities must consider when easing restrictions.

None of the above candidates are currently available in the UK, but analysis is ongoing to determine how the vaccines manufactured by AstraZeneca and Pfizer will be affected by the South African variant, with results expected soon.

Dr Susan Hopkins, of Public Health England, has meanwhile said the UK was looking at whether those who had already taken a Covid-19 vaccine would need a fresh shot to cover the risk posed by new mutations.

“It is unlikely that people would have to start [the vaccine treatment] again, it is much more likely that it would be a booster shot – a bit like the annual flu vaccine,” she said.

What next?

For now, the main objective is identifying cases of 501Y.V2, both symptomatic and asymptomatic, that are circulating in Britain and acting fast to cut its chains of transmission.

The decision to implement “surge” testing in the eight affected areas of England will give authorities a better idea of how widespread the South African variant is, and it’s crucial that local residents follow government calls to come forward and get tested.

Local health teams will be carrying out door-to-door screening while mobile testing units are to be introduced to each area in a bid to pick up any further infections linked to 501Y.V2.

“This spread, even if small in scale, needs to be brought under control quickly, so Public Health England’s house-to-house checks, and intensive testing are the right thing to do,” says Simon Clarke, a professor in Cellular Microbiology at the University of Reading.

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