16.08.2022

What the South African variant means in the fight against Covid-19

Research conducted in South Africa suggests the vaccine offers “limited efficacy” against mild or moderate disease from B1351, and could be as low as 10 per cent. That means people who are exposed to the virus may still display some symptoms – a cough, a fever, tiredness or fatigue – and, as a result, will likely be capable of passing the infection on to others.

The rising threat posed by the South African coronavirus variant should not come as a surprise. Scientists were always aware that the virus would likely mutate, scuppering our attempts to limit its spread and reduce infections. That is the reality we now face – but it is far from catastrophic.

There are still many unknowns surrounding the variant, known as B1351, but the latest study examining its ability to diminish the effectiveness of the Oxford vaccine naturally raises concern.

However, the study did not provide clarity on whether the Oxford vaccine was effective against severe disease or hospitalisation, given that the trial participants – 2,000 in total – had an average age of 31 and were deemed healthy.

More analysis is needed to establish this and will likely follow in the coming weeks. But professor Shabir Madhi, who led the trial in South Africa, said the vaccine’s similarity to the candidate by Johnson & Johnson, which reduced severe disease by 89 per cent, suggested it would still prevent serious illness or death.

“There’s still some hope that the AstraZeneca vaccine might perform as well as the Johnson & Johnson vaccine in a different age group demographic that are at highest risk of severe disease,” he said on Monday.

Professor Sarah Gilbert, who designed the Oxford vaccine, has admitted that the jab may not be capable of reducing the number of cases but expressed her confidence over the weekend that “we still won’t be seeing the deaths, hospitalisations and severe disease.” This, she said, would be “really important for healthcare systems”.

As well as generating neutralising antibodies that appear capable of preventing the escalation of disease, it is expected that the vaccine stimulates other vital parts of the immune system – such as the T cell response – to tackle B1351.

Separate studies have shown that the vaccines produced by Pfizer, Moderna and Novavax still offer protection against the South African variant – 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.

Johnson & Johnson and Novavax have meanwhile reported that none of the people who received a vaccine in their South African trials died of Covid-19 – another win for humanity in its fight against coronavirus, despite the complications posed by B1351.

In South Africa, where the variant accounts for an estimated 90 per cent of cases nationally, authorities have decided to pause the rollout of the Oxford vaccine. It marks a major blow for the country, which last week received a million doses of the jab ahead of its planned rollout to frontline health workers.

If further studies confirm the vaccine’s effectiveness in preventing serious disease, South African health officials said they would consider resuming use of the jab – but such a setback has shaken the world, demonstrating how these new and emerging variants have the ability to place humanity on the back foot in its fight against Covid-19.

For the UK, there is no current need to adopt such measures. Both the Oxford and Pfizer vaccines have shown to be highly effective in neutralising the Kent variant, which is now dominant in the British population. This means the country can push ahead with its impressive rollout and alleviate pressure on the NHS.

Nonetheless, there can be no room for complacency. So far there have only been 147 confirmed cases of the South African variant in Britain. But with scientists sequencing up to 10 per cent of all positive infections, it’s highly likely there are many more infections caused by B1351 in other parts of the UK that have not yet been picked up.

Professor Mike Tildesley, who advises the government as a member of the Scientific Pandemic Influenza Group on Modelling (SPI-M), said it was “very possible” that B1351 is already quite widespread in the UK.

The current lockdown measures will prevent B1351 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 B1351 to continue circulating.

Prof Tildesley, an infectious disease expert at Warwick University, said the findings on the Oxford vaccine could therefore have “significant implications” on Britain’s lockdown-easing plans.

“It means that even with high levels of vaccination there will be a lot of people that could potentially get infected and could potentially pass it on and it may mean that more restrictions might be needed for longer if we can’t get on top of this,” he said on Monday.

Nonetheless, professor Jonathan Van-Tam, deputy chief medical officer for England, said it was unlikely that B1351 would replace the Kent variant and become dominant in the UK.

“I’m not seeing, and the early modelling data do not suggest, a transmissibility advantage for this virus,” he said on Monday. “So, that being the case, it’s not going to kind of overrun or overtake the current B117 virus in the next few months, or that is the most likely scenario, that it won’t happen.”

Even so, work is now underway to tweak many of the current generation of vaccines to capture the specific “escape” mutations seen in B1351, which are thought to allow the virus to evade our antibody response.

Leave a Reply

Your email address will not be published.