AstraZeneca COVID-19 vaccine has hit a minor stumbling block after a small clinical trial raised doubts about its efficacy against the South African variant of the coronavirus.On Sunday, South Africa halted its planned rollout following preliminary data that suggested that the AstraZeneca vaccine offers only “minimal protection against mild or moderate disease” from the B.1.351 variant, now the dominant form of the coronavirus in the country.
Past COVID-19 infection not a ‘free pass’ from new variants, experts say The AstraZeneca study involved 2,000 healthy volunteers with an average age of 31 and showed just 22 per cent were protected against mild to moderate cases of the disease.The research has not yet been peer-reviewed and did not.