Boosters are coming; who will get them and when?

COVID-19 booster shots may be coming for at least some Americans but already the Biden administration is being forced to scale back expectations — illustrating just how much important science still has to be worked out.

The initial plan was to offer Pfizer or Moderna boosters starting Sept. 20, contingent on authorization from U.S. regulators. But now administration officials acknowledge Moderna boosters probably won’t be ready by then — the Food and Drug Administration needs more evidence to judge them. Adding to the complexity, Moderna wants its booster to be half the dose of the original shots.

As for Pfizer’s booster, who really needs another dose right away isn’t a simple decision either. What’s ultimately recommended for an 80-year-old vaccinated back in December may be different than for a 35year-old immunized in the spring — who likely would get a stronger immunity boost by waiting longer for another shot.

FDA’s scientific advisers will publicly debate Pfizer’s evidence Sept. 17, just three days before the administration’s target. If the FDA approves another dose, then advisers to the Centers for Disease Control and Prevention will recommend who should get one.