If it determines the injury in the British trial was caused by the vaccine, the FDA could pause the trial. In that case, the trial might be continued without fear, because the illness was not specific to the vaccine. The AstraZeneca trial in the United States has a separate safety board. If the AstraZeneca vaccine fails, the U.S. government is supporting six other COVID vaccines in the hope at least one will succeed. The potential problems with the AstraZeneca vaccine show this to be a wise investment, Adalja said.