The United States Food and Drug Administration has decided to review a new vaccine for influenza, despite rejecting the application earlier this month.  NEW YORK: Vaccine manufacturer Moderna said Wednesday (Feb 18) the US Food and Drug Administration walked back its previous position and agreed to review the company's new mRNA-based flu shot. Last week the US firm said the federal vaccine regulator rejected the application for review of the new shot, calling its clinical trial inadequate. But