The additional doses will be available to people eight months after they received their second dose. Top U.S. health officials announced Wednesday that the country plans to start offering Covid-19 booster shots to all Americans beginning the third week of September, citing evidence that protection against infection is waning, as the highly contagious delta variant continues to spread. "Having reviewed the most current data, it is our clinical judgment that the time to lay out a plan for Covid-19 boosters is now," U.S. Surgeon General Vivek Murthy said Wednesday during a briefing of the White House Covid-19 task force. Such data, unveiled Wednesday by the Centers for Disease Control and Prevention, stops short of proving that a third dose would be any more effective in preventing severe outcomes than the current two-dose series. But officials said the plan, backed by heads of the CDC, the National Institutes of Health and the Food and Drug Administration, is designed more as an offensive move against Covid-19 in advance of winter. "You don't want to find yourself behind, playing catch up," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said during the briefing. "Better to stay ahead of it than chasing after it." The booster effort will likely mirror the original vaccine rollout, with health care workers, nursing home residents and people over age 65 first in line. Those shots are expected to be available the week of Sept. 20, assuming the FDA and the CDC sign off on the safety and effectiveness of the doses by that point. 2 more Florida school districts defy DeSantis' order and vote for mask mandates Census servers hit by cyber attack, but U.S. count unaffected, watchdog says Booster Shots in the Fall