FDA poised to approve Moderna's mRNA flu vaccine despite earlier rejection

Four months after refusing to review Moderna's application, FDA advisers appear ready to endorse the same vaccine based on largely the same evidence.

Earlier this year, the FDA issued Moderna a Refusal-to-File letter, effectively rejecting the company’s application before a full scientific review could begin.

At the centre of the decision was Vinay Prasad, then director of the FDA’s Center for Biologics Evaluation and Research (CBER), who argued that Moderna had tested its vaccine against the wrong benchmark.

Because the vaccine was intended for older adults, the FDA said Moderna should have compared it against one of the influenza vaccines routinely recommended for people aged 65 and older, rather than a standard-dose flu shot.

The decision immediately sparked controversy.