Here’s what pausing the AstraZeneca-Oxford coronavirus vaccine trial really means
A single volunteer’s illness has sparked a temporary halt to the late-stage clinical trial of a leading coronavirus vaccine, an action that highlights the level of rigor needed to ensure that a vaccine is safe and effective, experts say. AstraZeneca, which is developing the vaccine in concert with the University of Oxford, pushed pause on September 8 after a study volunteer in the United Kingdom had a suspected serious reaction. The hiatus will allow an independent review board to decide what to do next. The illness may turn out to have nothing to do with the vaccine. If so, the trial, which may enroll as many as 50,000 people worldwide, including up to 30,000 in the United States, may resume. If the vaccine caused the illness — known as a serious adverse event — it could spell the end for AstraZeneca’s vaccine hopes. But experts say the pause is part of the...