AstraZeneca downgrades vaccine efficacy to 76% in updated US trial results

AstraZeneca said on Thursday its COVID-19 vaccine was 76% effective at preventing symptomatic illness and completely stopped severe or critical forms of the disease, citing a new analysis of up-to-date results for its major U.S. trial.

U.S. health officials earlier in the week publicly rebuked the drugmaker for using "outdated information" when calculating that the vaccine was 79% effective.