The FDA has approved Moderna’s mFlusiva as the first mRNA seasonal flu vaccine for use in the United States, clearing it for adults 50 to 64 and granting accelerated approval for those 65 and older while requiring postmarket trials to confirm effectiveness in seniors.
The agency’s decision marks a notable moment in vaccine policy, coming as Health and Human Services Secretary Robert F. Kennedy Jr. has been a vocal critic of mRNA technology. The approval required a unanimous advisory committee vote that the benefits outweigh the risks for people ages 50 to 64, plus support for accelerated approval in those 65 and older.
The approval did not come smoothly. Earlier objections within the agency, including a reported initial refusal to review the application, raised concerns about internal resistance to mRNA products. That pushback reverberated beyond FDA walls and became part of the wider debate over mRNA platforms and federal vaccine policy under HHS leadership.
A top FDA official earlier this year initially refused to review the vaccine before the agency reversed course a week later under pressure.
Former agency vaccine chief Vinay Prasad said the application was rejected because of Moderna’s decision to compare its vaccine to a standard flu shot in adults 65 and up, rather than the high-dose shot. Moderna said FDA had initially signed off on the trial design.
Application refusals are rare, and critics said the episode pointed to a hostile environment for mRNA vaccines under Kennedy.
Moderna’s mFlusiva must still go through the CDC recommendation process before it can expect routine insurance coverage, because the CDC’s Advisory Committee on Immunization Practices normally authorizes which populations should receive newly approved vaccines. A court ruling has blocked the ACIP from meeting with its current membership, leaving the timetable for a formal recommendation unclear and creating uncertainty for coverage and distribution planning.
In practice, doctors could prescribe mFlusiva without an ACIP recommendation, but insurers may not be required to cover the shot until CDC guidance is finalized. The final public-health rollout will therefore hinge on administrative processes and legal developments that are separate from the FDA’s biological determination of safety and efficacy for the indicated groups.
The broader backdrop is a marked shift in HHS priorities under Secretary Kennedy, who has repeatedly expressed skepticism about mRNA vaccines and their long-term safety. Kennedy has described COVID-19 shots in stark terms and has redirected funding away from multiple mRNA development projects, framing the move as a shift toward what he calls safer and broader vaccine platforms.
On Aug. 5, 2025, HHS announced it was canceling or scaling back 22 mRNA vaccine-development projects worth nearly $500 million, a decision Kennedy framed as moving resources toward other approaches. That change in funding priorities has unsettled industry and scientific communities that view mRNA as a leading platform for rapid vaccine development.
Kennedy has also said he stopped receiving annual flu shots in 2005 because of concerns about possible side effects, a personal health choice he has made public and has used to justify policy shifts. His stance has created tension between his agency’s leadership and the vaccine advisory experts who still broadly endorse annual flu vaccination for most people.
Health and Human Services Secretary Robert F. Kennedy Jr. told USA TODAY he stopped taking flu shots in 2005 because of his concerns about side effects, including suspicions about what damaged his voice.
Kennedy, 71, said he got annual flu shots through the mid-1990s. But he said he gave them up for good in 2005 as he became more aware of possible side effects.
The independent vaccine advisory panel’s unanimous backing of mFlusiva’s benefit-risk balance for the 50-to-64 age group underscores that career scientists and clinicians still find the data convincing for those adults. The accelerated approval for older adults acknowledges both potential benefit and the need for confirmatory postmarket studies to demonstrate real-world effectiveness among seniors.
That nuance is important: accelerated approval allows vaccines to reach patients sooner while requiring additional evidence, but it also means questions remain and public confidence depends on transparent follow-up. For a party that favors clear science, accountability, and sound oversight, demanding rigorous postmarket verification is consistent with protecting seniors and ensuring taxpayer confidence in federally authorized products.
The FDA move will now land on the desk of the CDC director to manage recommendations and on insurers who will weigh coverage without a finalized ACIP guidance. Political leaders and clinicians on both sides of the aisle will watch how the postmarket data come in, how the CDC handles recommendations amid the legal limbo, and whether insurance coverage follows to make the vaccine broadly accessible.
Ultimately, the mFlusiva approval raises practical and political questions about how new vaccine technologies are evaluated, funded, and deployed under changing federal leadership. The situation will test whether regulatory decisions can remain tethered to data and whether follow-up studies and clear communication can keep public trust intact while enabling promising medical advances to reach patients.
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