FDA Approves mFLUSIVA, First mRNA-Based Flu Vaccine

The FDA approved mFLUSIVA (mRNA-1010), Moderna's investigational seasonal influenza vaccine, for use in all adults 50 years of age and older, the company announced. The approval makes mFLUSIVA the first mRNA-based vaccine cleared for seasonal flu prevention in the United States and Moderna's fourth FDA-approved product overall.¹

The decision follows a unanimous recommendation from the FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC) earlier this year and caps a review process marked by an initial regulatory setback.^1-3

"The FDA approval of mFLUSIVA, our fourth approved product in the United States and the first mRNA-based flu vaccine, demonstrates the continued strength and versatility of our mRNA platform," Stéphane Bancel, chief executive officer of Moderna, said in a news release.¹ "Flu remains a significant public health challenge, and mFLUSIVA provides an important new option for America's seniors. This approval also reflects the ongoing potential of our mRNA platform to help address important public health challenges through continued scientific innovation.”

A Two-Tiered Approval Pathway

The FDA's approval of mRNA-1010 in adults 50 through 64 years of age is based on results from a randomized, observer-blind, active-controlled phase 3 clinical trial (NCT06602024) that enrolled 40,805 adults 50 years of age and older across 11 countries. The trial's primary objectives were to evaluate the safety and reactogenicity of mRNA-1010 and to assess its relative vaccine efficacy compared with a standard-dose active comparator against reverse transcription polymerase chain reaction–confirmed, protocol-defined influenza-like illness caused by any influenza A or B strain.¹

Use in adults 65 years of age and older was granted under accelerated approval, based on a separate randomized, observer-blind, active-controlled trial (NCT05827978) that enrolled 2992 adults 65 years of age and older in the United States. That study's primary objective was to evaluate the immunogenicity of mRNA-1010 against a high-dose inactivated influenza vaccine comparator, and effectiveness in this age group is further supported by a descriptive analysis of relative vaccine efficacy from the larger phase 3 trial.¹

Confirmation of clinical benefit in adults 65 years and older will be assessed through a postmarketing clinical trial, a condition Moderna agreed to as part of its regulatory strategy for the older population. The phase 3 program overall demonstrated an acceptable safety profile for mRNA-1010, with no new safety concerns identified.^1-3

That accelerated-approval trial, published in Vaccine, was a 3-part study (Part A, adults 18 years and older; Part B, adults 18 to 64 years; Part C, adults 65 years and older) that randomly assigned adults 65 and older to a single 50-μg dose of mRNA-1010 (n = 1507) or a licensed high-dose quadrivalent comparator vaccine (n = 1496).⁴

mRNA-1010 elicited hemagglutination inhibition titers against vaccine-matched strains that were statistically noninferior to, and met prespecified superiority criteria over, the high-dose comparator across all 4 influenza A and B strains in this age group.⁴

Solicited adverse reactions were more frequent with mRNA-1010 than with the comparator vaccine, though reactions were generally lower in frequency and severity among adults 65 years and older than in younger trial participants, and the most common reactions across all age groups were injection-site pain, fatigue, myalgia, and headache. Across the full 3-part program, which evaluated more than 4200 participants, no new safety concerns were identified.⁴

The study authors noted that it was designed to assess safety and immunogenicity rather than clinical efficacy and that a separate ongoing phase 3 efficacy trial (NCT06602024)—the trial underlying the vaccine's approval in adults 50 to 64 years—was initiated to evaluate relative vaccine efficacy against influenza-like illness in roughly 34,000 adults 50 years and older.⁴

A Long and Contentious Path to Approval

The approval caps a review process that included a rare regulatory reversal. The FDA initially issued a refusal-to-file letter for Moderna's application, objecting to the trial's use of a standard-dose comparator vaccine in participants 65 years and older, since that age group is preferentially recommended to receive high-dose or adjuvanted influenza vaccines.³

Following a Type A meeting between Moderna and the FDA's Center for Biologics Evaluation and Research, the agency agreed to formally review an amended application under a bifurcated regulatory strategy: full approval for adults 50 to 64 years and accelerated approval for adults 65 years and older, paired with a commitment to conduct postmarketing studies against high-dose comparators.³

"Discussions with the company led to a revised regulatory approach and an amended application, which FDA accepted," Andrew Nixon, a spokesperson for the US Department of Health and Human Services, said at the time.³ "FDA will maintain its high standards during review and potential licensure stages as it does with all products."

That amended application went on to earn a unanimous 9-0 vote from VRBPAC in favor of mRNA-1010's benefit-risk profile for both age groups, the panel's first new vaccine review since 2023.²

"We appreciate the thoughtful review by the members of VRBPAC and their recognition of the clinical evidence supporting mRNA-1010," Bancel said following the vote.² "Influenza continues to cause substantial illness and hospitalizations among older adults each year. We believe mRNA-1010 has the potential to provide an important new option for seasonal flu prevention and further demonstrate the versatility of our mRNA platform."

What This Means for Pharmacists

For pharmacists managing inventory and patient counseling, mFLUSIVA represents a differentiated, nonegg-based option built on the same messenger RNA platform used in COVID-19 vaccines. One practical advantage is production speed: traditional flu vaccines require roughly a 6-month production window, while the mRNA platform can shorten that to 2 or 3 months, potentially allowing for closer strain matching and faster response if a new influenza strain emerges during the season.²

Data presented to VRBPAC underscored the scale of the disease burden the vaccine is meant to address, with the CDC reporting at least 32 million influenza cases and 24,000 deaths in the most recent season, and roughly 85% of those eligible for vaccination remaining unvaccinated.²

Moderna expects mFLUSIVA to be available for the 2026-2027 respiratory virus season, with supply reaching select retailers in the coming weeks, alongside the company's other approved mRNA products: Spikevax (COVID-19 vaccine, mRNA), mRESVIA (respiratory syncytial virus vaccine), and mNEXSPIKE (COVID-19 vaccine, mRNA). Regulatory submissions for mRNA-1010 have also been accepted for review in the European Union, Canada, and Australia, with additional country submissions planned during 2026.¹

REFERENCES

1. Moderna receives U.S. FDA approval for influenza vaccine mFLUSIVA. News release. Moderna, Inc. August 5, 2026. Accessed August 6, 2026. https://www.accessnewswire.com/newsroom/en/healthcare-and-pharmaceutical/moderna-receives-u.s.-fda-approval-for-influenza-vaccine-mflusiva-1201472

2. Gallagher A. FDA committee votes unanimously to recommend mRNA flu vaccine. Drug Topics. June 19, 2026. Accessed August 6, 2026. https://www.drugtopics.com/view/fda-committee-votes-unanimously-to-recommend-mrna-flu-vaccine

3. Nowosielski B. FDA reverses stance, initiates formal review for Moderna flu vaccine. Drug Topics. February 19, 2026. Accessed August 6, 2026. https://www.drugtopics.com/view/fda-reverses-stance-initiates-formal-review-for-moderna-flu-vaccine

4. Soens M, Ananworanich J, Hicks B, et al. A phase 3 randomized safety and immunogenicity trial of mRNA-1010 seasonal influenza vaccine in adults. Vaccine. 2025;50:126847. doi:10.1016/j.vaccine.2025.126847