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Moderna’s once-rebuffed mRNA flu shot to face scrutiny from FDA adcomm

Key Takeaway: The FDA's advisory committee will review Moderna's mRNA flu vaccine application next month, following an earlier refusal to file. The meeting will assess the vaccine's safety and efficacy for older adults. Despite initial rejection due to concerns over trial standards, a compromise has been reached for review. A decision is anticipated in August.
Price reaction · baseline $47.26 (2026-05-21 close) · hit after-hours · 2 other MRNA headline(s) in the window, move may be shared
day 0 close · peak
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POSITIVE FACTORS

  • FDA will review Moderna's mRNA flu vaccine application.
  • The advisory committee meeting will involve independent experts.
  • Moderna's application seeks both regular and accelerated approval.

CONCERNS & RISKS

  • FDA initially rejected Moderna's application for not following guidance.
  • Controversy surrounding the FDA's handling of vaccine applications.
  • High-level resignations at the FDA following the incident.

BiopharmaWatch Analysis

From our catalyst data and publicly available data · not financial advice
Best trade, last catalyst
+47%
120-day peak, hindsight
Typical move
5.1%
average across 3 past catalysts
Cash runway
~22 mo
Low dilution risk
Lead asset
mRNA-1645-eODGT8
Phase 1 · HIV Infections

Full Press Release Details

The FDA will convene its Vaccines and Related Biological Products Advisory Committee next month to assess Moderna’s investigational mRNA flu vaccine, which in February was the center of controversy after the agency initially refused to accept the application for review.
The adcomm meeting—only the second in the past 10 months, followingone for AstraZeneca’scancer drugs last month, will take place on June 18, according to aFederal Register noticeposted Friday. The vaccine panel, which typically consists of independent outside experts, will discuss the safety and efficacy of Moderna’s MFLUSIVA for the prevention of flu in patients 50 years and up, as caused by the influenza virus subtypes A and B.
It isn’t yet clear what the specific points of discussion will be during the adcomm as the FDA hasn’t released its briefing documents yet. As of writing, the meeting is also not yet listed on the agency’scalendar.
In early February, the FDAslappedModerna’s flu application with a refusal-to-file letter, declining to accept the submission for review. The letter, which was signed by former Center for Biologics Evaluation and Research Director Vinay Prasad, contended that Moderna’s pivotal trial for the vaccine used a control group that “does not reflect the best-available standard of care.”
“The FDA rejected Moderna’s application for filing because the company refused to follow very clear FDA guidance from 2024 to test its product in a clinical trial against a CDC-recommended flu vaccine to compare safety and efficacy,” spokesperson Andrew Nixonsaidshortly after the agency turned down Moderna’s application.
This rebuff drew strong blowback from the industry—so much so that the Department of Health and Human Services had to publicly defend Prasad and then–FDA Commissioner Marty Makary was called into President Donald Trump’s office to hear his “frustration” over the agency’shandling of vaccine issuesmore broadly,Politicoreported at the time.
Moderna and the FDA have since arrived at a compromise, with the regulatoragreeingto accept the application for review. The amended application is seeking regular approval for use in adults 50 to 64 years and accelerated approval for those 65 years and up. A decision is expected in August.
Shortly after, aninvestigation was launchedinto Prasad’s professional conduct, with accusations flying that he berated his staff and retaliated against reviewers who questioned his decisions. A few weeks later, Makary announced that Prasad would be leaving the FDA onApril 30.
A series of high-level reassignments and resignations at the FDA have followed his departure, including that ofMakary himself, plus Prasad ally and Acting CBER DirectorKatherine Szarama, Center for Drug Evaluation and Research (CDER) Acting DirectorTracy Beth Høeg, and the agency’s chief of staff and chief AI officer. The turnover at the top of CBER and CDER brings the total number of people who have run those two review units since Trump took office to six each.

Frequently Asked Questions

When is the FDA advisory committee meeting for Moderna's vaccine?

The FDA advisory committee meeting will take place on June 18.

What was the reason for the initial rejection of Moderna's application?

The FDA rejected the application due to concerns over the trial's control group.

What approvals is Moderna seeking for its flu vaccine?

Moderna is seeking regular approval for ages 50-64 and accelerated approval for 65 and up.

What changes occurred at the FDA following the controversy?

There were high-level resignations and reassignments at the FDA after the incident.

Last updated: May 22, 2026