David Kaslow, a top career FDA scientist, authored a memo objecting to David Prasad's decision to block Moderna's mRNA flu vaccine review, according to Stat News and The Wall Street Journal. Moderna had submitted trial plans for a Phase 3 clinical trial involving nearly 41,000 adults aged 50 and older, using an existing licensed vaccine as a comparator. Nine companies have faced similar surprise rejections from Prasad, raising industry concerns. Kaslow's memo detailed why the review should proceed, but Prasad, a political appointee with no vaccine expertise, overruled the scientists. Moderna adjusted its trial plan based on FDA feedback but was still rejected. Moderna is now expected to potentially re-submit data focusing on a different age group, possibly after demonstrating humility. This move has created an environment of mistrust within the FDA, with multiple complaints filed against Prasad, including allegations of sexual harassment and retaliation.