A new kind of flu vaccine is moving a step closer to the U.S. market. Federal health advisers on Thursday recommended approval of a shot made with the same mRNA technology that was key to ending the pandemic. Moderna is seeking Food and Drug Administration approval for mFlusiva as an option for people 50 and older. There already are numerous types of flu vaccines to choose from, but experts say adding an mRNA option could be useful. Moderna is seeking full approval for people ages 50 to 64 and authorization for use in those 65 and older while it conducts additional testing.