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FDA Panel Unanimously Backs Moderna mRNA Flu Shot, 27% Efficacy

6/19/2026

Summary

FDA Backs Moderna

The FDA panel voted 9-0 to recommend Moderna’s mRNA flu vaccine mFlusiva for adults 50-64 and 65+, a decision be made by Aug. 5.
A 40,000-person study of those 50+ showed a 27% flu-case reduction, with a trial in seniors 65+ showing an immune response versus the vaccine.
Approval would require a trial of 400,000 adults 65+ over two seasons, while HHS Secretary Robert F. Kennedy Jr. cancelled $500 million in mRNA research.

Summary

FDA Softens Stance

Vinay Prasad and former commissioner Marty Makary have left the FDA, ushering in more traditional leadership.
Analyst Myles Minter and analyst Mani Foroohar said the FDA found no major deficiencies and indicated a less-harsh regulatory stance.
The confirmatory study will enroll 800,000 participants across two flu seasons to assess efficacy in elderly and immunocompromised groups.
Moderna’s Rituparna Das stressed communication about benefits and typical mRNA side effects is crucial for uptake.

Summary

Moderna Redesigns Flu

The mRNA platform enables manufacturers to redesign the flu vaccine within weeks, potentially avoiding seasonal strain mismatch.
Flu vaccine effectiveness in late 2025/early 2026 was 11-46% in children and 23-34% in adults, while historically performance has ranged from 19% to 60%, underscoring Moderna’s cited unmet need.
Nine influenza vaccines are approved in the United States, but none use mRNA technology, though mRNA vaccines are approved for COVID-19 and RSV.

Summary

Moderna Secures Backing

Moderna's shares rose 3.5% to $63.96, their highest level since 2024, after the advisory panel's unanimous backing.
The mRNA flu shot would compete with existing influenza vaccines from Sanofi, GSK, CSL Seqirus and AstraZeneca.
A Moderna executive said the company aims to have the vaccine available to patients for the upcoming flu season.

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FDA Backs Moderna

The FDA panel voted 9-0 to recommend Moderna’s mRNA flu vaccine mFlusiva for adults 50-64 and 65+, a decision be made by Aug. 5.
A 40,000-person study of those 50+ showed a 27% flu-case reduction, with a trial in seniors 65+ showing an immune response versus the vaccine.
Approval would require a trial of 400,000 adults 65+ over two seasons, while HHS Secretary Robert F. Kennedy Jr. cancelled $500 million in mRNA research.

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