Scientists are developing booster jabs to tackle Covid-19 variants, a health minister says, amid concerns about the Oxford-AstraZeneca vaccine’s efficacy against the South Africa strain.

A small study suggests the jab offers “minimal protection” against mild disease from the South Africa variant.

But UK ministers have sought to reassure the public over the vaccine.

Edward Argar said the government was anticipating that an annual jab could be required to combat variants.

He also said there was “no evidence” the Oxford-AstraZeneca vaccine was not effective at preventing severe illness.

Some 147 cases of the South Africa variant have been found in the UK.

Scientists have warned that it could be more widespread, however the version of the virus first discovered in Kent remains the dominant strain in the UK.

South Africa has put its rollout of the Oxford-AstraZeneca vaccine on hold as it waits for further advice on how best to proceed in light of the preliminary findings.

Scientists say the strain – also known as 501.V2 or B.1.351 – accounts for 90% of new coronavirus cases in the country.