FDA Reverses Course: Greenlights Review of Moderna’s mRNA Flu Vaccine Amid Industry Backlash

February 19, 2026

SILVER SPRING, MD — In a stunning regulatory about-face, the U.S. Food and Drug Administration (FDA) announced on February 18, 2026, that it will officially review Moderna’s experimental mRNA-based influenza vaccine, mRNA-1010. The decision comes just one week after the agency abruptly rejected the application, sparking a firestorm of criticism from public health experts and industry leaders. The reversal marks a pivotal moment for the future of vaccine technology and suggests a high-stakes compromise between the federal government and biotechnology innovators aiming to protect adults aged 50 and older before the 2026-2027 flu season.

A Week of Regulatory Whiplash

The controversy began on February 10, when the FDA issued a “refusal-to-file” (RTF) letter to Moderna. The agency’s initial rejection was spearheaded by official Vinay Prasad, who overruled career scientists to argue that Moderna’s clinical trial design was flawed. Specifically, the FDA took issue with the trial’s use of a standard-dose flu shot as the “control arm” for participants over 65, rather than the high-dose version typically recommended for seniors.

However, following a “Type A” meeting—the agency’s most urgent dispute-resolution track—the FDA pivoted. Under the leadership of Commissioner Marty Makary, the agency has now accepted an amended filing. The new path forward includes a request for full approval for adults aged 50–64 and “accelerated approval” for those 65 and older, contingent upon Moderna conducting a post-marketing study that compares mRNA-1010 directly against high-dose vaccines.

The Science: Why mRNA for Flu?

Unlike traditional flu vaccines, which are often grown in chicken eggs—a process that can take six months and allow the virus to “drift” or mutate—Moderna’s mRNA-1010 uses messenger RNA. This technology instructs the body’s own cells to produce specific proteins that mimic the flu virus, triggering an immune response.

“The availability of another option for influenza vaccination, particularly if it is using a technology which allows more rapid changes… will potentially be a major step forward,” said Robert H. Hopkins Jr., MD, medical director of the National Foundation for Infectious Diseases.

Key Clinical Findings

The application is backed by a Phase 3 trial (P304) involving nearly 41,000 participants across 11 countries. Key data points include:

• Relative Vaccine Efficacy (rVE): The vaccine was 26.6% more effective than standard-dose vaccines at preventing influenza.

• Senior Protection: For adults 65 and older, mRNA-1010 showed 27.4% superior effectiveness against major circulating strains, including A/H1N1 and A/H3N2.

• Rapid Production: The mRNA platform allows manufacturers to update the vaccine strain selection much closer to the start of the flu season, potentially offering a better “match” for the viruses actually in circulation.

Industry and Expert Reaction

The initial rejection sent shockwaves through the biotech sector, particularly as it followed a move by HHS Secretary Robert F. Kennedy Jr. to slash $500 million in federal mRNA research funding last August.

Michael Osterholm, PhD, MPH, director of the University of Minnesota’s Center for Infectious Disease Research and Policy (CIDRAP), expressed frustration with the agency’s recent inconsistency. “We don’t have any idea why they reversed course,” Osterholm noted. “This current situation demonstrates how out of control we are in the FDA’s consideration and review of currently licensed vaccines and potential new vaccines.”

Moderna CEO Stéphane Bancel maintained a diplomatic tone following the reversal, stating, “Pending FDA approval, we look forward to making our flu vaccine available later this year so that America’s seniors have access to a new option to protect themselves.”

Public Health Impact: The Stakes for Seniors

Influenza remains a persistent and deadly threat in the United States. According to CDC data, the virus causes between 140,000 and 710,000 hospitalizations annually. The burden is heaviest on the 116 million U.S. adults over the age of 50, who account for the vast majority of flu-related deaths.

Current vaccines generally offer 40% to 60% efficacy, but that protection can drop significantly if the vaccine strains do not perfectly match the circulating virus. The “just-in-time” manufacturing capability of mRNA could bridge this gap.

Comparison of mRNA-1010 Features

Limitations and Potential Risks

While the reversal is a win for Moderna, the vaccine still faces hurdles. Critics point out that by comparing mRNA-1010 to a “standard-dose” vaccine in the 65+ group, Moderna may have made their results look more impressive than they would have been against the “high-dose” shots seniors usually receive.

Furthermore, while billions of mRNA COVID-19 doses have been administered, skeptics continue to raise concerns about rare side effects like myocarditis. However, Moderna reported no new safety signals in its massive influenza trials, with most side effects being limited to temporary injection-site pain or fatigue.

Looking Ahead

The FDA has set a decision deadline of August 5, 2026. If approved, mRNA-1010 could be available in pharmacies and clinics by the fall. This timeline is critical, as the industry watches for signals of how the current administration will handle future vaccine innovations, including “combo” shots that target both COVID-19 and the flu in a single injection.

For now, healthcare providers are encouraged to continue following current CDC guidelines for the upcoming season while keeping an eye on the August regulatory milestone.

References

• Reuters. (2026, February 18). US FDA to initiate review of Moderna’s influenza vaccine. * CIDRAP. (2026, February 17). Double-reverse: FDA now says it will review Moderna’s mRNA flu vaccine. Source

Medical Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals before making any health-related decisions or changes to your treatment plan. The information presented here is based on current research and expert opinions, which may evolve as new evidence emerges.