Tensions over vaccine policy intensified as Vinay Prasad, the FDA’s top vaccines regulator, defended proposed changes while a group of former FDA commissioners publicly criticized his plans. Prasad told attendees at a closed investor conference that media narratives had distorted his intent to require longer, larger studies for vaccine updates, framing the proposal as policy modernization. In parallel, twelve former FDA commissioners published a pointed critique — widely reported in outlets including BioCentury and the New England Journal of Medicine — warning that the proposed vaccine standard changes risk public health by upending longstanding regulatory practice. The ex‑officials argued the shift would be sweeping and potentially harmful to timely vaccine deployment. The public pushback and Prasad’s defense set up a high-stakes debate inside the agency and among stakeholders about trial size, evidentiary standards for vaccine modifications, and the balance between safety and speed. Biopharma companies that develop vaccines are monitoring the debate closely, as any formal policy change would alter development plans and regulatory expectations.