CBER director Vinay Prasad publicly defended his proposed vaccine-policy changes at a closed-door investor forum, blaming "misleading media narratives" for the escalation of criticism. His remarks followed an open rebuke from a group of nearly a dozen former FDA commissioners who published concerns in the New England Journal of Medicine and other outlets. The former commissioners argued that Prasad’s plan to lengthen and enlarge vaccine update studies would upend long-standing regulatory practice and could hinder timely vaccine adaptations. Prasad has cited a probe into COVID-19 vaccine safety as the justification for rethinking standards. The clash has amplified political and stakeholder scrutiny of the agency’s biologics arm, raising questions about future vaccine guidance and the stability of policy signals for vaccine developers and public-health partners.