"A two-dose regimen of [the vaccine] did not show protection against mild-moderate Covid-19 due to [the South African variant]", the study says, as quoted by The Financial Times.
According to the newspaper, the study involved 2,025 participants, with a median age of 31. Half of them were given placebo, while the other half got at least one dose of the Oxford/AstraZeneca coronavirus vaccine. None of the participants died or was hospitalized.
"We do believe our vaccine could protect against severe disease, as neutralizing antibody activity is equivalent to that of other Covid-19 vaccines that have demonstrated activity against more severe disease, particularly when the dosing interval is optimised to 8-12 weeks," an AstraZeneca spokesperson said as quoted by The Financial Times, adding that other immune responses, such as T-cells, "may remain intact" against the South African variant.
According to the spokesperson, AstraZeneca has already started adapting its vaccine to the South African strain, so that it is ready for fall deliveries, if needed.
Earlier this month, the University of Oxford said that the AstraZeneca vaccine had proven its effectiveness against the UK coronavirus variant.