By LAURAN NEERGAARD and MIKE STOBBE
WASHINGTON (AP) — Federal health officials say millions more Americans can get a COVID-19 booster and choose a different vaccine for that next shot. Certain people who received Pfizer vaccinations months ago already are eligible for a booster. The Centers for Disease Control and Prevention on Thursday said specific Moderna and Johnson & Johnson recipients should qualify, too. And in a bigger change, the agency is allowing the flexibility of “mixing and matching” that extra dose. The Food and Drug Administration had already authorized such an expansion of the nation’s booster campaign on Wednesday, and it was also endorsed Thursday by a CDC advisory panel.