FDA Denies Moderna's Bid for Innovative mRNA Flu Vaccine
On Tuesday, Moderna revealed that the Food and Drug Administration has declined to review its application for a novel flu vaccine developed using mRNA technology, which garnered a Nobel Prize. This refusal marks a significant moment in the ongoing scrutiny of vaccine approvals.
Under the leadership of Health and Human Services Secretary Robert F. Kennedy Jr., the FDA has intensified its examination of vaccines, particularly those employing mRNA technology, which Kennedy has publicly criticized both before and after assuming his role.
Moderna received a "refusal-to-file" letter from the FDA, which raised concerns about the methodology of a clinical trial involving 40,000 participants. This trial indicated that the new vaccine demonstrated greater efficacy in adults aged 50 and older compared to standard flu shots currently in use.
Dr. Vinay Prasad, the FDA's vaccine director, articulated in his letter that the application lacked an "adequate and well-controlled trial," as it did not compare the new vaccine against "the best-available standard of care in the United States at the time of the study." The letter, which Moderna made public, referenced guidance provided to the company in 2024 during the Biden administration that was not adhered to.
Moderna contends that the FDA had previously indicated it was acceptable to use the standard-dose flu shot chosen for the trial, although another brand specifically recommended for seniors was suggested for participants aged 65 and older. Despite this, Moderna asserts that the FDA permitted the study to proceed as initially designed.
Additionally, Moderna claims to have shared supplementary data from another trial that compared its new vaccine with a licensed high-dose shot intended for seniors.
In a statement, CEO Stephane Bancel emphasized that the FDA "did not identify any safety or efficacy concerns with our product" and criticized the decision as counterproductive to advancing innovative medicine in America.
Andrew Nixon, a spokesperson for the Department of Health and Human Services, clarified that the FDA's rejection stemmed from Moderna's failure to adhere to explicit guidance from 2024 regarding testing against a CDC-recommended flu vaccine for safety and efficacy comparisons.
"The most protective flu shots for seniors are a subset of high-dose flu shots recommended by the CDC Advisory Committee on Immunization Practices, which would have served as the proper control in this study," Nixon stated.
It is uncommon for the FDA to refuse to file an application, especially for a new vaccine, as this process typically involves extensive discussions between companies and FDA staff over several months or years.
Moderna has requested an urgent meeting with the FDA and has also sought approval for its vaccine in Europe, Canada, and Australia.
In recent months, FDA officials under Kennedy have reversed recommendations regarding COVID-19 vaccines, added warnings to leading mRNA vaccines, and removed critics from an FDA advisory panel.
Kennedy announced plans last year to cancel over $500 million in contracts aimed at developing mRNA vaccines, focusing instead on research into coronavirus and flu vaccines. He asserted that "mRNA technology poses more risk than benefits for these respiratory viruses," a claim that has drawn condemnation from vaccine experts. Jerome Adams, former surgeon general under President Trump, remarked on social media that this decision "is going to cost lives."
Historically, the FDA has allowed vaccine manufacturers to swiftly update annual flu shots targeting emerging strains by demonstrating an immune response in patients. This method is significantly more efficient than conducting long-term studies tracking flu incidence and patient outcomes.
However, an internal memo from Prasad last year indicated that this streamlined approach would no longer be permitted, prompting over a dozen former FDA commissioners to publicly denounce these statements.
Democratic Senator Patty Murray from Washington criticized the FDA's decision regarding Moderna, asserting that Kennedy's administration is "blocking an updated flu vaccine for no reason grounded in science." She expressed her frustration on social media, stating, "American vaccine policy has been hijacked by a conspiracy theorist—yet most Republicans are happy to just sit on their hands."
