Why Did the FDA Send Back Moderna's Flu Vaccine?

Calley Means says the FDA initially sent Moderna's mRNA flu-vaccine application back for another study because of concerns about the comparator and the size of the reported benefit. He says the trial used an outdated vaccine as its comparator and cites an absolute risk reduction of about 0.8 percent.

He also mentions deaths in the trial group but explicitly says the connection could not be definitively established. Deaths during a trial are not, by themselves, evidence that a vaccine caused them. Means describes Makary asking for more study rather than issuing an outright rejection, followed by lobbying pressure and a later review that he believes was improperly influenced. His allegations about that review and the vaccine's eventual approval are his account; this summary does not establish the product's safety, effectiveness or the cause of any death.