Some individuals will undoubtedly benefit from getting a booster shot, but experts say that the most important goal for the U.S. right now should be convincing vaccine holdouts to get their initial round of shots.

Where it stands: Two-thirds of Americans have received at least one dose of the vaccine, as has about 77% of the eligible population, according to the CDC.

Only 4.6% of the U.S. population has received a booster shot, as most Americans aren’t yet eligible. However, nearly 12% of people 65 and older have received a booster.