The Oxford-AstraZeneca vaccine might offer less protection against the South African strain of Covid-19. A small study suggests that the jab is not effective against mild illness caused by the South African variant. But scientists are hopeful that the vaccine will still work to prevent severe cases and deaths. In the UK, ministers have sought to reassure the public over the effectiveness of the Oxford-AstraZeneca vaccine, as experts warned it was "very possible" the South African variant is already quite widespread in the country. British Prime Minister Boris Johnson said the government is “very confident in all the vaccines that we're using.” More than 12 million people have been vaccinated in the UK so far. Meanwhile, scientists are already working on an Oxford-AstraZeneca booster against the South African variant, which could be ready as soon as this autumn.