South Africa has suspended its rollout of the Oxford-AstraZeneca vaccine after a study showed “disappointing” results against its new COVID-19 variant.
The African country has received 1 million doses of the AstraZeneca jab and was due to start vaccinating people next week but the trial carried out by the University of the Witwatersrand has delayed the rollout.
The study, involving around 2,000 people, found the vaccine offered “minimal protection” against mild and moderate cases of Covid-19. The trial has not yet been peer reviewed.
Scientists say the new strain accounts for 90% of new COVID-19 cases in South Africa.
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.
In the meantime, he said, the government will offer vaccines produced by Johnson & Johnson and Pfizer in the coming weeks.
“Unfortunately, the AstraZeneca vaccine does not work against mild and moderate illness,” Prof Shabir Madhi, who led the study, told the briefing.
He said that the study had not been able to investigate the vaccine’s efficacy in preventing more serious infections, as participants had an average age of 31 and so did not represent the demographic most at risk of severe symptoms from the virus.
Oxford’s lead vaccine developer, Prof Sarah Gilbert, noted that vaccines should still protect against severe disease.
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.
Early results from Moderna suggest its vaccine is still effective against the South Africa variant, while AstraZeneca has said its vaccine provides good protection against the variant first identified in the UK. Early results suggest the Pfizer-BioNTech vaccine also protects against the new variants.