FDA Shakes Up Flu Vaccine Industry with New Regulatory Moves

Regulators refuse to review Moderna's mRNA flu shot and require new safety warnings on existing vaccines, raising concerns about the future of US flu immunization.

Published on Feb. 12, 2026

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The US Food and Drug Administration has made a series of regulatory moves that have disrupted the flu vaccine industry. The agency refused to review Moderna's application for an mRNA-based flu vaccine, citing issues with the clinical trial design. The FDA has also required manufacturers of several existing flu shots to add more prominent safety warnings about the risk of febrile seizures, despite experts arguing the scientific evidence does not justify the labeling change. These actions, coming as health agencies and manufacturers normally gear up for the next flu season, have public health experts worried about the future of flu vaccines in the US.

Why it matters

The FDA's actions come at a critical time for flu vaccine development and distribution in the US. Strain selection and regulatory approval are key steps in the annual flu shot production process, and the agency's unpredictable moves have sown confusion. Experts are concerned these developments could discourage vaccine manufacturers from investing as heavily in the US market, potentially limiting options and access for Americans. The debate over febrile seizure risks also highlights the ongoing tensions around vaccine safety and the influence of anti-vaccine activists.

The details

In February 2026, the FDA's Center for Biologics Evaluation and Research (CBER) refused to review Moderna's application for an investigational mRNA-based flu vaccine, despite the vaccine candidate performing well in clinical trials. CBER director Vinay Prasad cited issues with the trial design, though Moderna said the decision was inconsistent with prior communications. This comes after the US government canceled around $500 million in grants for mRNA vaccine development. Separately, the FDA has required five manufacturers of flu vaccines approved for children to add more prominent safety warnings about the risk of febrile seizures. Experts argue the scientific evidence does not justify this labeling change, calling it the latest "assault" on the US vaccine program by regulators.

  • The FDA refused to review Moderna's mRNA flu vaccine application in February 2026.
  • In January 2026, the FDA sent letters to manufacturers requiring new febrile seizure safety warnings on pediatric flu shots.
  • Typically, the FDA's Vaccines and Related Biological Products Advisory Committee meets in February or March to select strains for the next flu season, but the agency canceled this meeting last year.

The players

Moderna

A pharmaceutical company that developed an investigational mRNA-based flu vaccine that the FDA refused to review.

Vinay Prasad

The director of the FDA's Center for Biologics Evaluation and Research, who decided not to review Moderna's mRNA flu vaccine application.

Robert F. Kennedy, Jr.

The US Department of Health and Human Services Secretary, who said mRNA vaccines "fail to protect effectively against upper respiratory infections like COVID and flu."

Robert Hopkins

A vaccinologist at the University of Arkansas for Medical Sciences and medical director of the National Foundation for Infectious Disease, who is concerned about the impact of the FDA's actions on flu vaccine development and access.

Paul A. Offit

A vaccinologist at the Children's Hospital of Philadelphia, who argues the scientific evidence does not justify the FDA's new febrile seizure safety warnings on flu vaccines.

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What they’re saying

“This decision by CBER, which did not identify any safety or efficacy concerns with our product, does not further our shared goal of enhancing America's leadership in developing innovative medicines.”

— Stéphane Bancel, CEO, Moderna (Moderna)

“I don't like to use the term chaos, but it seems apropos at this point.”

— Robert Hopkins, Vaccinologist, University of Arkansas for Medical Sciences

“It's very unusual for FDA to refuse to review a phase 3 trial they were involved in planning for.”

— Robert Hopkins, Vaccinologist, University of Arkansas for Medical Sciences

“I think it's just their constant assault on the vaccine program in this country. It's just a constant erosion.”

— Paul A. Offit, Vaccinologist, Children's Hospital of Philadelphia (C&EN)

“Among the billions of . . . doses administered to-date, febrile seizures have occurred in a limited subset of patients and have been addressed promptly by Sanofi and regulators.”

— Sanofi Spokesperson (Sanofi)

What’s next

The FDA has given manufacturers until February 8th to respond to the new febrile seizure safety warning requirements. It remains unclear if the agency will convene its Vaccines and Related Biological Products Advisory Committee to select strains for the 2026-2027 flu season.

The takeaway

The FDA's recent regulatory actions on flu vaccines, including refusing to review an innovative mRNA shot and mandating new safety warnings, have sown confusion and concern among public health experts. These moves could discourage vaccine manufacturers from investing in the US market, potentially limiting options and access for Americans at a time when flu remains a serious public health threat.