FDA Reverses Course on Moderna mRNA Flu Vaccine After Initial Rejection

The Food and Drug Administration announced it would review Moderna's application for a new mRNA flu vaccine for older adults, reversing a decision made just one week earlier to reject the application. On 10 February, the FDA told Moderna that it would not accept the company's application for a new influenza vaccine – a decision that reportedly involved senior leaders overruling advice from FDA staff, although the agency denied this was the case.

Moderna had apparently consulted the FDA on designs for clinical trials of its vaccine, per normal procedures, and while the agency did say it would prefer the company to also test against a high-dose flu vaccine control for older patients, it did sign off on the trial designs – only to later turn round and say they were inadequate.

Such a refusal-to-file is relatively rare. Gary Nabel, former head of the US National Institutes of Health's Vaccine Research Center and chief scientist at Sanofi, who now runs a vaccine and cancer startup, said it sets a 'destructive precedent that will undermine the future of vaccine development and the preeminence of American research'.

The FDA has approved two messenger RNA vaccines against RSV at the beginning of FDA Commissioner Makary's time. Asked if there was a contradiction between embracing genome editing, a technique used in gene therapy, but not mRNA vaccines, Makary said, "I think that would be quite a stretch to say we're not embracing mRNA vaccines. We've approved two mRNA vaccines at the beginning of my time."

Makary defended the department's decision to cut funding for the development of mRNA vaccines because companies that make the drugs can afford their own research. "There was funding for mRNA technology at HHS. That funding was pivoted to other causes, and I'll tell you why. It's not because we don't believe in mRNA technology. It's because the companies that made mRNA vaccines made over" substantial profits, Makary said. He said the government should fund research in areas that are underfunded, such as "bespoke conditions and rare diseases, conditions that have been in the blind spots of modern medicine."

When senior leaders can step in and – almost unilaterally – overrule procedure or ignore evidence-based decision-making, then an element of trust in the regulatory process is eroded. That applies whether such decisions impede or promote a drug's progress through the system. The current regime's unpredictability, combined with a clear distaste for vaccines, has the potential to inflict significant harm on future vaccine development. This extends beyond the US, since many countries with less well-developed regulatory infrastructure rely heavily on FDA decisions to inform their own approvals.