After Refusal-to-File, FDA Reconsiders Moderna’s mRNA Flu Vaccine With Higher Bar for Older Adults

After receiving a Refusal-to-File (RTF) letter from the FDA, Moderna held a Type A meeting with the agency and proposed a revised regulatory strategy for its investigational seasonal influenza vaccine, mRNA-1010. The company is seeking full approval for adults aged 50 to 64 years and accelerated approval for adults 65 years and older, with a postmarketing commitment to conduct an additional study in older adults.^1,2

Following the meeting, the FDA has accepted the amended biologics license application for mRNA-1010 and set a Prescription Drug User Fee Act (PDUFA) goal date of August 5, 2026. If approved, the vaccine would be available for US adults 50 years and older, including those 65 years and older, for the 2026 to 2027 flu season.¹

"We appreciate the FDA's engagement in a constructive Type A meeting and its agreement to advance our application for review," Stéphane Bancel, chief executive officer of Moderna, said in a news release. "Pending FDA approval, we look forward to making our flu vaccine available later this year so that America's [older adults] have access to a new option to protect themselves against flu."¹

Background on FDA RTF Letter for mRNA-1010

The RTF letter, signed by Vinayak Prasad, MD, MPH, director of the FDA’s Center for Biologics Evaluation and Research, stated that the application was declined solely because Moderna used a licensed standard-dose influenza vaccine as the comparator. The letter argued that the study lacked an “adequate and well-controlled” comparator representing the best available standard of care, although no FDA regulations or guidance explicitly require this, and the agency raised no safety or efficacy concerns about mRNA-1010.²

Expert Insight on mRNA-1010 and the FDA Decision

In an interview with Pharmacy Times, Tony Yang, ScD, LLM, MPH, professor of health policy at The George Washington University, discussed the FDA’s handling of Moderna’s flu vaccine, saying it reflects stricter expectations around trial design and comparators rather than skepticism toward messenger RNA (mRNA) technology.

Q: What does the FDA’s decision to move forward with reviewing Moderna’s mRNA flu vaccine indicate about the agency’s current regulatory approach to mRNA platforms?

Tony Yang, ScD, LLM, MPH: This looks less like “FDA is anti-mRNA” and more like “FDA is reasserting leverage on trial design and comparators.” The initial refusal centered on the view that Moderna didn’t use the “best-available standard of care” control for seniors, and leadership signaled they’re done “rubber-stamping” vaccines while leaning harder on postmarketing clinical trial requirements for novel products. mRNA isn’t getting special treatment—if anything, it’s getting a stricter, more public version of the usual rules.

Q: How typical is it to pursue full approval in 1 age group (50-64 years) and accelerated approval in another (65+ years), and what evidence will matter most for each?

Yang: It’s unusual in the sense that companies prefer one clean lane, but it’s logical here because high-dose flu vaccine isn’t approved for 50 to 64 [years of age], while it’s effectively the benchmark for 65 and older. For 50 to 64, the make-or-break evidence is standard approval stuff—immunogenicity and safety against an appropriate standard-dose comparator. For those [aged] 65 and older, accelerated approval will hinge on whether the immune data are persuasive enough as a surrogate and whether the confirmatory study is real, timely, and truly head-to-head against high dose in older adults (which Moderna has now agreed to do). FDA basically said: “[Older adults] get the toughest comparator, and you still owe us the outcomes story after launch.”

Q: What clinical advantages, if any, could an mRNA-based influenza vaccine offer over existing flu vaccine platforms, especially for older adults?

Yang: FDA explicitly wants the senior comparison to be against high dose, which tells you what “better” means in this category. The upside case for mRNA is mainly about design agility and the possibility of stronger or more consistent immune responses—but in older adults, the only advantage that matters is whether it can compete with (or beat) high-dose on real-world protection, not just lab markers. For seniors, the bar isn’t “works”—it [is] “works better than high-dose.”

Q: What should pharmacists be prepared to communicate to patients if an mRNA flu vaccine becomes available before the next flu season?

Yang: Expect confusion around “accelerated approval,” so the clean message is, “For [ages] 65 and older, this may come with required follow-up studies; for [ages] 50 to 64, it’s being reviewed in the usual way.”

Also, be ready for patients who want to wait for the new thing—pharmacists should discourage delay and frame it as “one more option,” not a reason to skip timely vaccination. And if it’s approved, the likely timeline being discussed is availability for the 2026 [to] 2027 season—so counseling will matter fast, before seasonal demand peaks.

REFERENCES

1. Moderna announces the U.S. Food and Drug Administration will initiate the review of its investigational seasonal influenza vaccine submission. News release. Moderna. February 18, 2026. Accessed February 18, 2026. https://feeds.issuerdirect.com/news-release.html?newsid=8923338804483797&symbol=MRNA

2. Ferruggia K. FDA declines to review Moderna’s mRNA-1010 flu vaccine application, citing comparator concerns. Pharmacy Times. February 11, 2026. Updated February 12, 2026. Accessed February 18, 2026. https://www.pharmacytimes.com/view/fda-declines-to-review-moderna-s-mrna-1010-flu-vaccine-application-citing-comparator-concerns