Pushing back against U.S. health officials, AstraZeneca says new analysis confirms efficacy of its Covid-19 vaccine

Rejecting sharp criticism from U.S. government scientists, AstraZeneca said Wednesday night that its Covid-19 vaccine was 76% effective at reducing the risk of symptomatic Covid-19, and 100% effective against severe disease, in a new analysis of its large U.S.-based clinical trial.