A patient receives a Covid-19 vaccine booster shot at a Pfizer-BioNTech vaccination clinic in Southfield, Michigan, on Sept. 29, 2021.

Emily Elconin | Reuters

All adults in the U.S. are now eligible to receive Pfizer‘s and Moderna‘s Covid vaccine boosters, after the Centers for Disease Control and Prevention authorized the shots for the general public Friday. The move allows an extra dose of protection for tens of millions of fully vaccinated Americans as cases climb and public officials worry the nation could face another surge during the winter.

CDC Director Rochelle Walensky signed off on the booster shots hours after the agency’s independent panel of vaccine scientists unanimously endorsed opening up eligibility to everyone 18 and older at least six months after they received their…