After discussions with the FDA, Moderna has withdrawn its application for a combination shot, which had demonstrated efficacy in eliciting antibodies in data announced earlier this month.

Covid vaccines will soon be required to go through more rigorous trials to ensure that they really are beneficial for people who aren’t at high risk.

Several of the committee members asked at Thursday’s meeting about the FDA’s new vaccine approval framework. Some expressed concern that changing the strain targeted in this year’s vaccine might decr...