On Mar. 22, 2021, Oxford University announced that a Phase III study of the Oxford-AstraZeneca coronavirus vaccine conducted by AstraZeneca in the U.S., Chile and Peru had shown that vaccine is safe and highly effective, adding to previous trial data from the United Kingdom, Brazil and South Africa, as well as real-world impact data from the UK.

These data show that the vaccine was 79% effective against symptomatic COVID-19, and 100% effective against severe, or critical symptomatic COVID-19.