Preliminary data from a study conducted at Oxford University indicates that the Covid-19 vaccine developed by AstraZeneca is effective against the P1, or Brazilian, variant, a source with knowledge of the study told Reuters on Friday.

The data indicated that the vaccine will not need to be modified in order to protect against the variant, which is believed to have originated in the Amazonian city of Manaus, said the source, who requested anonymity as the results have not yet been made public...