AstraZeneca's COVID-19 vaccine candidate begins late-stage U.S. study

AstraZeneca's COVID-19 vaccine candidate begins late-stage U.S. studyTrial participants will receive either two doses of the experimental vaccine, dubbed AZD1222, four weeks apart, or a placebo, the company said. The trial is being conducted under U.S. government's Operation Warp Speed program, which aims to accelerate development, manufacturing and distribution of vaccines and treatments for COVID-19. U.S. President Donald Trump has said a vaccine for the novel coronavirus could be available before the Nov. 3 presidential election, much sooner than most experts anticipate.