The U.S. is expanding COVID-19 boosters, ruling that 16- and 17-year-olds can get a third dose of Pfizer’s vaccine. The U.S. and many other nations already were urging adults to get booster shots to pump up immunity that can wane months after vaccination, calls that intensified with the discovery of the worrisome new omicron variant. On Thursday, Dec. 9, 2021 the FDA gave emergency authorization for 16- and 17-year-olds to get a third dose of the vaccine made by Pfizer and its partner BioNTech — if it’s been six months since their last shot. (AP Photo/Mark Lennihan, file) U.S. health authorities said Thursday that 16- and 17-year-olds should get a booster dose of Pfizer’s COVID-19 vaccine once they’re six […]