The Food and Drug Administration commissioner repeatedly said patients should rely on guidance from their doctors.

The FDA's approval was based on a study of 11,400 people age 12 and older that compared the new low-dose vaccine with Moderna's existing vaccine. It found the new vaccine was safe and was at least as effective - and more by some measures - than the original shot, the company said.

The FDA will no longer recommend annual COVID vaccinations for healthy people younger than 65. A North Carolina doctor says that most Americans will still be eligible to receive shots through the list.