In this March 2, 2021, file photo, Hollie Maloney, a pharmacy technician, loads a syringe with Pfizer’s COVID-19 vaccine at the Portland Expo in Portland, Maine. An influential federal advisory panel overwhelmingly rejected a plan Friday, Sept. 17, to offer Pfizer booster shots against COVID-19 to most Americans, dealing a heavy blow to the Biden administration’s effort to shore up people’s protection amid the highly contagious delta variant. (AP Photo/Robert F. Bukaty, File)