By LINDSEY TANNER and MIKE STOBBE, AP Medical Writers The first COVID-19 shots for U.S. infants, toddlers and preschoolers moved a step closer Wednesday. The Food and Drug Administration's vaccine advisers gave a thumbs-up to vaccines from Moderna and Pfizer for the littlest kids. The outside experts voted unanimously that the benefits of the shots outweigh any risks for children under 5 — that’s roughly