British drugmaker AstraZeneca said on Saturday its vaccine developed with Oxford University appeared to offer only limited protection against mild disease caused by the South African variant of COVID-19.
That's based on early data from a trial.
The study from South Africa's University of the Witwatersrand and Oxford University showed the vaccine had significantly reduced efficacy against the variant, according to a Financial Times report.
The so-called British, South African and Brazilian coronavirus variants are among those currently most concerning for scientists and health experts.
These appear to spread more swiftly than others.
The newspaper said that none of the trial participants - of which there were over 2,000 - had been hospitalized or died.
However, AstraZeneca said it's not been able to properly ascertain the vaccine's effect against severe disease and hospitalization--
given that the subjects were predominantly young healthy adults.
The company said it believed its vaccine could protect against severe disease, given that the neutralizing antibody activity was equivalent to that of other COVID-19 vaccines that have demonstrated protection.
While thousands of individual changes have arisen as the virus mutates into new variants, only a tiny minority are likely to be important or change the virus in a significant way - according to the British Medical Journal.