South Africa has suspended use of a coronavirus vaccine developed by AstraZeneca and Oxford University amid concerns over its efficacy against a variant of the virus that has been driving a second wave of infections.

Health Minister Zweli Mkhize said on Sunday (February 7) that the government would await advice from scientists on how best to proceed.

"So it’s a temporary issue that we have to hold onto the AstraZeneca. It is temporary until we figure out these issues, what is the next step supposed to be, when we know those steps, then of course we bring it back."

Prior to widespread circulation of the variant, known as 501Y.V2, researchers said the AstraZeneca vaccine was showing efficacy of around 75%.

But analysis of infections by the new variant shows the vaccine only reducing the risk of moderate or mild infection by 22%.

Researchers said the figure was not statistically significant due to the trial's design, but it is well below the benchmark of at least 50% regulators have set for vaccines to be considered effective.

The study did not assess whether the vaccine helped prevent severe COVID-19 because it involved mostly relatively young adults.

But on Monday (February 8) the trial's lead investigator, Professor Shabir Madhi, said there was still some hope that the vaccine would prevent severe disease.