FDA rejects Moderna’s mRNA flu vaccine application

Food and Drug Administration Refusal to review the application From biotech company Moderna to approve mRNA-based influenza vaccine.

Agency decision Moderna It was announced in a press release dated February 10, 2026is the latest step in efforts by federal health officials under Health and Human Services Secretary Robert F. Kennedy Jr Disrupting long-standing public health practices related to vaccine access and approval, as well as reshaping the public’s perception of vaccine safety.

Messenger RNA (mRNA)-based vaccines came to the fore in the early days of the COVID-19 pandemic, but researchers are now using the technology to create other vaccines, as well as treatments for the virus. Diseases such as cancer and autoimmune disorders. the Nobel Prize-winning technology maybe Especially promising for influenza Because vaccines can be developed quickly each season to match mutating influenza strains.

However, Kennedy and other federal health officials, including the US Food and Drug Administration, expressed this There is particular skepticism towards mRNA-based vaccinesraising safety concerns while not providing reliable data about the health risks to which they are exposed Stop funding research related to its development.

‘ asked the conversation Anna Santosrochmana Villanova University law professor and vaccine policy expert, to explain the importance of the FDA’s decision and how it fits into the rapidly changing landscape of public health policy.

What exactly did the FDA do, and why was it unusual?

In December 2025, Moderna I submitted an application to the FDA To approve an mRNA influenza vaccine for adults 50 years and older. The vaccine was tested in clinical trials that included more than 40,000 people. In response to the request, The agency sent Moderna A “Application Rejection” letter.dated February 3, 2026. This is a type of notice that the regulator sends to companies when it deems there is a new drug or vaccine The application must be incomplete.

Because companies developing new products meet with the Food and Drug Administration (FDA) early in the process to agree on approval requirements, It’s a rarity for the agency To take this action. What’s more, there was Very few occasions The FDA diverged significantly from other major drug regulators around the world. But in this case, it’s drug regulators in Canada, Europe and Australia Moderna’s request for review was accepted.

Of particular concern is that multiple FDA scientists and other staff have confirmed this Moderna’s application is expected to be reviewed. Director of the FDA’s Office of Vaccine Research and Review, David Kaslow, Wrote a recommendation note It is being reviewed. But Vinay Prasad, who runs the centre, does so He supervises the Office of Vaccine Researchoverturn the decision.

Managers rarely object to agency scientists, especially regarding vaccines. But this is it At least the fourth time Prasad did this Since his appointment to the US Food and Drug Administration in 2025.

What reasons did the FDA give for its decision?

Moderna has taken an unusual step Announcing the FDA’s rejection and Release the agency letter. The letter states that Moderna did not conduct an “adequate and well-controlled” study because it did not compare patients receiving its vaccine to patients receiving what the agency claimed was “the best standard of care available.”

In the United States, Standard dose influenza vaccines It’s approved for all people over 6 months old, but health authorities recommend that adults over 65 receive the more effective dose. Moderna’s announcement cited language used by the FDA when approving the company’s clinical trial protocol in 2024. The agency had originally proposed For people 65 and older, the company compares the effectiveness of its vaccine to the most effective dose. But after reviewing Moderna’s protocol, the FDA approved it The standard vaccine was deemed “acceptable.”“.

Besides the fact that the FDA approved Moderna’s trials, I believe the agency’s claim that the company did not use the “best available standards of care” is problematic because it does not reflect the legal requirements for vaccine approval. Although this phrase sounds formal, it is Can’t find it anywhere In the Food and Drug Administration (FDA) code or guidance for companies developing vaccines.

Instead, the FDA requires the company to submit data from “Adequate and well controlled studies“The use of standard-dose influenza vaccines meets the requirements because they are widely used across age groups.

Shortly after Moderna announced the rejection, health news agency STAT quoted an unnamed FDA official as saying that if Moderna “Show some humility“, the agency may still review the application, but only for people under 65. Imposing this restriction after declining to review an application has no basis in law because the FDA approves clinical trial standards early, in consultation with companies.

From a legal perspective, the FDA’s decision likely meets the so-called “Arbitrary and capriciousStandard, because it appears that the agency has changed its position without good reason for the change. If the court makes such a decision, it will It could overturn the FDA decision. However, this process will take time.

Does the FDA decision reflect a change in vaccine policy?

This is the first time the FDA has tried to block review of a vaccine for reasons unrelated to safety or effectiveness. This step, which is linked to a A broader strategy by federal health officials Under Kennedy, this signals an escalation in the agency’s efforts to interfere with established procedures for testing vaccines.

In April 2025, Kennedy announced new vaccines It will require additional clinical trials. In November 2025, Prasad issued an internal FDA memo Claiming that mRNA-based COVID-19 vaccines have killed children. Although he did not provide any evidence, he said that in response to the alleged deaths: Widespread changes to Vaccine approval requirements They were coming.

The FDA’s rejection of Moderna’s request appears to be Prasad’s established policy.

What might this mean for vaccines moving forward?

On a practical level, the fact that the FDA has now drafted requirements that cannot be found in law creates significant uncertainty for companies with pending or upcoming vaccine orders. This is because manufacturers now have reason to worry that they may invest resources in the long process of developing a vaccine, only to receive a similarly unpredictable rejection.

On a larger scale, with many areas in Vaccine law and policy are in turmoilincentives for vaccine manufacturers to bring vaccines to market are diminishing. In January 2026, even before the flu shot was rejected, Moderna’s CEO said the company was Reducing vaccine development .

Finally, the FDA’s move threatens to exacerbate the problem Lack of confidence in vaccinesin line with a broader push from federal health officials to A question that science settled a long time ago.