Twelve former FDA commissioners publicly rebuked CBER head Vinay Prasad’s plan to tighten evidence requirements for updated vaccines, framing the proposal as a major regulatory shift. The New England Journal of Medicine article criticizing the plan prompted urgent debate inside and outside the agency about the impact on vaccine approvals and public-health preparedness. Prasad defended the approach at a closed-door investor conference, saying longer, larger studies are needed for modernized vaccine decisions. His remarks underscore a widening rift between agency leadership and industry/public-health figures over the balance between speed and evidentiary rigor for vaccine updates.