South Africa has put its roll-out of the Oxford-AstraZeneca vaccine on hold after a study showed “disappointing” results against its new Covid variant.
Scientists say the strain accounts for 90% of new Covid cases in South Africa.
The study, involving around 2,000 people, found the vaccine offered “minimal protection” against mild and moderate cases of Covid-19.
South Africa has received 1m doses of the AstraZeneca jab and was due to start vaccinating people next week.
Speaking at an online news conference on Sunday, South African Health Minister Zweli Mkhize said his government would wait for further advice on how best to proceed with the Oxford-AstraZeneca vaccine in light of the findings. The trial was carried out by the University of the Witwatersrand but has not yet been peer reviewed.
In the meantime, he said, the government will offer vaccines produced by Johnson & Johnson and Pfizer in the coming weeks.
Prof Sarah Gilbert, Oxford’s lead vaccine developer, said vaccines should still protect against severe disease.
She said developers were likely to have a modified version of the injection against the South Africa variant, also known as 501.V2 or B.1.351, later this year.
Experts say vaccines could be redesigned and tweaked to be a better match for new variants in a matter of weeks or months if necessary.