https://apnews.com/bd0bcbcfbd76b178d430000c94bf7a7e > 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.