In a long-awaited meeting on America’s crash program to deliver vaccines against the Covid-19 coronavirus, leaders of the program reviewed the measures they have taken to assure the effectiveness and safety of the vaccines. The U.S. Food and Drug Administration convened a panel of independent vaccine experts to ask questions during the Thursday online session. The meeting was designed to reassure the public on the integrity and transparency of the FDA’s vaccine oversight, as the agency has wrestled with political pressure and pockets of public vaccine hesitancy.