On Mar. 22, 2021, the NIH announced that results from a large clinical trial in the U.S. and South America indicated that AstraZenecaﾒs COVID-19 vaccine, AZD1222, was well-tolerated and protects against symptomatic COVID-19 disease, including severe disease or hospitalization.

The independent Data and Safety Monitoring Board (DSMB) overseeing the trial identified no safety concerns related to the vaccine. The UK-based global biopharmaceutical company AstraZeneca developed the vaccine and led the trial as regulatory sponsor.