evidence: US health advisers said on Thursday that some Americans who received Moderna’s Covid vaccine should get a half-dose booster to bolster protection against the virus. The panel of advisers to the Food and Drug Administration voted unanimously to recommend a booster shot for seniors, adults with other health problems, jobs or living situations that put them at increased risk for Covid. [...] "It’s important to remember that the vaccines still provide strong protection against serious outcomes" such as hospitalization and death from Covid, said FDA vaccine chief Peter Marks.