NEW YORK (AP) — U.S. health officials have announced plans to dispense COVID-19 booster shots to all Americans to shore up their protection amid the surging delta variant and evidence that the vaccines’ effectiveness is falling. The plan, as outlined by the director of the Centers for Disease Control and Prevention and other top health authorities, calls for booster doses eight months after people get their second shot of the Pfizer or Moderna vaccine. The booster doses could begin the week of Sept. 20.