Researchers in Brazil began administering an experimental coronavirus vaccine developed by Oxford University to volunteers, according to AFP.

The vaccine, developed together with pharmaceuticals group AstraZeneca, is one of the most promising of the dozens that researchers worldwide are racing to test.

The Federal University of Sao Paulo, which is coordinating the study in Brazil, said in a statement its researchers had begun issuing the first doses to health workers with a high likelihood of coming into contact with the new coronavirus, including doctors, nurses and ambulance drivers.