South Africa is halting its rollout of the AstraZeneca-University of Oxford Covid-19 vaccine, after a study showed the drug failed to prevent mild and moderate cases of the virus variant.

Africa’s hardest-hit nation was due to start vaccination in the coming days with a million doses of the vaccine developed AstraZeneca and Oxford.

“We have decided to put a temporary hold on the rollout of the (AstraZeneca) vaccine. More work needs to be done,” said South African Health Minister Zweli Mkhize during a virtual press conference.

The University of Witwatersrand, Johannesburg, which conducted the trial involving around 2,000 people, said in a statement on Sunday that the AstraZeneca vaccine ‘provides minimal protection against mild-moderate Covid-19 infection’ from the South African variant.

Despite the setback for the country, officials have said vaccine deliveries from other producers would soon be available.

‘In the next four weeks, we will have the J&J and Pfizer,’ said Mkhize, referring to vaccines made Johnson & Johnson and Pfizer/BioNTech.

Discussions with other vaccine producers are reportedly ongoing, particularly Moderna and the makers of the Russian Sputnik V jab.

Mkhize said the 1.5 million AstraZeneca vaccines obtained South Africa, which will expire in April, will be kept until scientists give clear indications on their use.

‘The second generation of the vaccine to fight all variants will take longer to produce,’ said Salim Abdool Karim, epidemiologist, and co-chair of the scientific committee at the South African health ministry.

South Africa plans to vaccinate at least 67 percent of its population the end of the year, or around 40 million people.

The country has recorded nearly 1.5 million infections and more than 46,000 deaths from the virus.