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Friday, December 2, 2022

South Africa halts AstraZeneca vaccine rollout over new variant

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South Africa has put its rollout of the Oxford-AstraZeneca vaccine on hold after a study showed “disappointing” results against its new Covid variant.

Scientists say the variant accounts for 90% of latest Covid cases in South Africa .

The trial, involving some 2,000 people, found that the vaccine offered “minimal protection” against mild and moderate cases.

But experts are hopeful that the vaccine will still be effective at preventing severe cases.

South Africa has recorded quite 1.4 million coronavirus cases and 46,000 deaths since the pandemic began, consistent with data collated by Johns Hopkins University. The country has received a million doses of the Oxford-AstraZeneca jab and was thanks to start vaccinating people within the coming days.

South African Health Minister Zweli Mkhize said his government would await further advice on how best to proceed with the AstraZeneca vaccine in light of the findings.

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In the meantime, he said, the govt would offer vaccines produced by Johnson & Johnson and Pfizer within the coming weeks.

What does it mean for serious cases?

The trial was administered by researchers at the University of the Witwatersrand in South Africa and therefore the UK’s Oxford University , but has not yet been peer reviewed.

The trial’s chief investigator, Prof Shabir Madhi, said it showed that “unfortunately, the AstraZeneca vaccine doesn’t work against mild and moderate illness”.

Prof Madhi said the study had not been ready to investigate the vaccine’s efficacy in preventing more serious infections, as participants had a mean age of 31 then didn’t represent the demographic most in danger of severe symptoms from the virus.

The vaccine’s similarity to at least one produced by Johnson & Johnson, which was found during a recent study to be highly effective at preventing severe disease in South Africa , suggested it might still prevent serious illness, consistent with Prof Madhi.

“There’s still some hope that the AstraZeneca vaccine might well perform also because the Johnson & Johnson vaccine during a different age bracket demographic that I address of severe disease,” he told the press.

Other experts were also hopeful that the vaccine remained effective at combating more serious cases.

“What we’re seeing from other vaccine developers is that they need a discount in efficacy against a number of the variant viruses and what that’s looking like is that we might not be reducing the entire number of cases, but there’s still protection therein case against deaths, hospitalisations and severe disease,” Prof Sarah Gilbert, Oxford’s lead vaccine developer, told the Andrew Marr Show on Sunday.

She said developers were likely to possess a modified version of the injection against the South Africa variant, also referred to as 501.V2 or B.1.351, later this year.

Ministers within the UK have sought to reassure the general public over the effectiveness of the Oxford-AstraZeneca vaccine. Vaccines Minister Nadhim Zahawi said the injection seemed to work well against dominant variants within the UK, while Health Minister Edward Argar said there was “no evidence” the vaccine wasn’t effective at preventing severe illness.

We should be careful about rushing to judgement

Viruses mutate – so what is happening is not surprising.

The mutations seen in South Africa change the part of the virus that the vaccines target. It means all the vaccines that have been produced so far are likely to be affected in some way.

Trials for Novavax and Janssen vaccines that were carried out in South Africa showed less effectiveness against this variant. Both are currently before the UK regulator.

Therefore the news about Oxford-AstraZeneca does not come out of the blue.

The fact it now only has “minimal” effect according to reports is concerning – the other vaccines showed effectiveness in the region of 60% against the South African variant.

But we should be careful about rushing to judgement. The study was small so there is only limited confidence in the findings.

What is more, there is still hope the vaccine will prevent serious illness and hospitalisation.

What this once again illustrates is the pandemic is not going to end with one Big Bang. Vaccines are likely to have to change to keep pace with the virus.

Progress will be incremental. But vaccines are still the way out of this.

What do we know about the variant?

The South Africa variant carries a mutation that appears to make it more contagious or easy to spread.

However, there is no evidence that it causes more serious illness for the vast majority of people who become infected. As with the original version, the risk is highest for people who are elderly or have significant underlying health conditions.

At least 20 other countries including Austria, Norway and Japan, have found cases of the variant.