The FDA’s decision comes at a time when the number of cases of COVID variant NB.1.8.1 have been rising globally, which according to the World Health Organization, has been detected in 22 countries as of May 18.

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.