AstraZeneca's coronavirus vaccine has started Phase three trials in the US

British drugmaker AstraZeneca said Monday it has started Phase 3 trials of its experimental coronavirus vaccine in the United States, becoming the third company to start late-stage trials of a vaccine to prevent Covid-19.

source https://www.cnn.com/2020/08/31/health/astrazeneca-vaccine-phase-3-trial/index.html