U.S. health authorities are facing a critical decision: whether to offer new COVID-19 booster shots this fall that are modified to better match the latest changes of the shape-shifting coronavirus. Moderna and Pfizer say their candidates targeting the super-contagious omicron variant will be an improvement. But the original omicron already has been replaced by its even more contagious relatives, with no way to know what version will spread this fall and winter. Advisers to the Food and Drug Administration will debate a recipe change Tuesday, and regulators promise a quick final decision.
US grapples with whether to modify COVID vaccine for fall
