this U.S. Food and Drug Administration Moderna announced on Tuesday that the FDA was declining to consider an application for a new flu vaccine using mRNA technology, a decision that could delay the rollout of a vaccine designed to provide stronger protection for older adults.

Moderna said it received an email from U.S. Food and Drug AdministrationThe Center for Biologics Evaluation and Research (CBER) noted the lack of “adequate and well-controlled” comparison group studies that “do not reflect the best available standard of care.”

Moderna CEO Stéphane Bancel said the FDA’s decision did not “identify any safety or effectiveness issues with our products” and “does not further our shared goal of enhancing U.S. leadership in developing innovative medicines.”

“A thorough review of a flu vaccine submission using an FDA-approved vaccine as a comparator in a study that was discussed and agreed upon with CBER prior to the start of the study should be non-controversial,” Bancel said in a statement. “We look forward to working with CBER to learn a path forward as quickly as possible so that America’s seniors and those with underlying medical conditions can continue to have access to American-made innovations.”

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The FDA declined to review Moderna’s application for a new mRNA flu vaccine, citing concerns about the design of its late-stage clinical trials. (iStock)

The rare FDA decision comes as health ministers intensify scrutiny of vaccine approvals Robert F. Kennedy Jr.Over the past year, he has criticized mRNA vaccines and rolled back certain COVID-19 vaccination recommendations.

Kennedy previously Removal of federal members The government’s vaccine advisory group appointed new members and canceled a $500 million contract for the mRNA vaccine.

The FDA is authorizing COVID-19 vaccines for use in the fall only for high-risk groups. Last May, Kennedy announced that the vaccines would be removed from the CDC’s routine immunization schedule for healthy children and pregnant women.

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The FDA’s refusal to review Moderna’s mRNA flu vaccine comes amid a broader shift in vaccine policy under Health Secretary Robert F. Kennedy Jr. (Jason Mendes/Getty Images)

According to Moderna, the decision to deny the submission was based on the company’s choice of comparator in the Phase 3 trial – a licensed standard-dose seasonal flu vaccine – which the FDA said did not reflect “the best available standard of care.”

Moderna said the decision contradicted previous written communications from the FDA, including 2024 guidance, which stated that a standard dose comparator was acceptable but recommended a higher dose for participants over 65 years old.

Moderna said the FDA “did not raise any objections or clinical reservations about the adequacy of the Phase 3 trial at any time after the submission of the protocol in April 2024 or before the start of the study in September 2024.”

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Moderna said it received a “refusal to submit” letter from the FDA for its new mRNA flu vaccine, a move that could delay the vaccine’s rollout. (iStock)

In August 2025, after completing its Phase 3 efficacy trial, Moderna said it held a Hold a pre-commission meeting with CBERwhich requires that supporting analyzes of comparators be included in submissions and states that the data will be “a significant issue during the review of your BLA.”

Moderna said it provided the additional analysis requested by CBER in its submission, noting that “at no time in written feedback or meetings prior to the submission did CBER indicate that it would refuse to review the document.”

The company requested a Category A meeting with CBER to understand the basis for the RTF letter, adding that regulatory reviews were continuing in the European Union, Canada and Australia.

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Fox News has contacted Department of Health and Human Services for comment.

Fox News Digital’s Alex Miller and The Associated Press contributed to this report.