New FDA guidelines – a response by experts in the field

In a NEJM Perspective, 12 former FDA commissioners warn that new internal FDA directives on vaccine regulation threaten evidence‑based policy, innovation, and public health. The piece responds to a memo by the current CBER director, Vinay Prasad, which characterizes FDA scientists who raise external concerns as “unethical” and “illegal,” instructs dissenters to resign, and proposes sweeping changes to how vaccines are updated and approved. The authors argue that both the substance of these proposals and the unilateral way they are being introduced break with long‑standing norms of open scientific debate, public transparency, and advisory‑committee oversight that have historically underpinned the FDA’s legitimacy. A central concern is the memo’s rejection of immunobridging as a regulatory tool for updating vaccines against well‑characterized pathogens such as SARS‑CoV‑2 and influenza. Immunobridging uses validated immune correlates (e.g., antibody titers) to infer protection, allowing timely updates without repeating large efficacy trials for every new strain or serotype,...