FDA Blocks Moderna mRNA Flu Vaccine Despite Variant Surge
The FDA rejected Moderna’s application for a next-generation mRNA flu vaccine on Tuesday, declining to review the shot despite the technology’s proven effectiveness in COVID-19 vaccines. The agency did not cite safety or efficacy concerns but instead objected to Moderna’s clinical trial design, according to a letter from Center for Biologics Evaluation and Research director Vinay Prasad. The FDA demanded the company test its vaccine against a CDC-recommended flu shot to compare safety and efficacy, claiming Moderna’s trial design exposed older participants to substandard care.
Virologist Angie Rasmussen criticized the FDA’s process, stating the rejection lacked “a thoughtful, systematic, transparent review of the evidence that relies on diverse expertise” and represented an individual decision by Prasad rather than an informed institutional review. Rasmussen emphasized that mRNA vaccine technology’s flexibility allows rapid adaptation to emerging virus variants, a capability conventional flu vaccines cannot match. The agency’s decision comes as the 2024-2025 flu season has proven exceptionally severe, with at least 22 million infections and 12,000 deaths documented in the United States, driven significantly by the arrival of subclade K.
The FDA’s rejection aligns with Health and Human Services Secretary Robert F. Kennedy Jr.’s broader campaign to overhaul America’s vaccine schedule. Kennedy, a longtime vaccine skeptic, has repeatedly attacked mRNA technology and overseen the Trump administration’s cuts to vaccine research funding. The decision reflects an ideological effort to undermine vaccine development infrastructure rather than evidence-based regulatory assessment.
Rasmussen noted that if mRNA vaccine platforms had been recognized and deployed in time, updated flu shots could have been formulated during the current season to address subclade K, potentially preventing significant illness and death. The FDA’s rejection eliminates this adaptive public health advantage and blocks advancement of a proven technology platform that could address future viral threats with unprecedented speed.