Food and Drug Administration scientists evaluating a potentially new messenger RNA flu vaccine from Moderna have expressed skepticism about the evidence supporting its benefits, according to documents filed days before a crucial advisory committee meeting.
On Thursday, the FDA will convene a panel of experts to discuss use of the shot, dubbed mFlusiva and in development for seasonal influenza. Panelists are set to vote on whether the benefits of vaccination outweigh the risks in people either between the ages of 50 and 64, or those who are 65 and older. Moderna hopes the discussion will set the stage for approval of a vaccine U.S. regulators controversially refused to review earlier this year before abruptly changing course.
Documents filed on Tuesday summarize the position of staff scientists and provide a window into how the agency views the data Moderna has compiled to date. They show that reviewers found no “major deficiencies” with the vaccine, but unearthed gaps in evidence that leave unclear how well it works, particularly in the elderly.
Moderna showed in testing that its shot reduced the likelihood of flu-like illness by 27% compared to a standard-dose vaccine in study results recently published in the New England Journal of Medicine. But staff reviewers pointed to key limitations in those findings. The trial only incorporated data from one flu season, raising questions about how the shot might perform in seasons with different viral strains. There wasn’t a large enough sample size to clearly show whether mFlusiva can protect against influenza B.
