Diseases & conditions

Study: Moderna's Flu Vaccine Shows 26.6% Superior Relative Efficacy

Published JUN 30 2025

Story

Above: A researcher works in the lab at the Moderna Inc. headquarters in Cambridge on March 26, 2024. Image credit: Adam Glanzman/Bloomberg/Getty Images

The Facts

Moderna announced positive Phase 3 results for its mRNA-1010 seasonal influenza vaccine on Monday, demonstrating 26.6% superior relative vaccine efficacy compared to a licensed standard-dose seasonal flu vaccine in adults aged 50 years and older.
Reuters
Fox4Kc
USA Today
The Phase 3 study enrolled 40,805 adults aged 50 years and older across 11 countries, with participants receiving either mRNA-1010 or a standard-dose licensed comparator vaccine, followed for a median of six months.
Bloomberg.com
Fox4Kc
USA Today
The vaccine demonstrated strong efficacy across all influenza strains, with 29.6% efficacy against A/H1N1, 22.2% against A/H3N2, and 29.1% against B/Victoria lineages, as well as 27.4% efficacy in adults 65 years and older.
Reuters
Fox4Kc
CNBC
Safety data showed most adverse reactions were mild, with injection site pain being the most common local reaction, while fatigue, headache, and myalgia were the most common systemic reactions reported.
Fierce Biotech
Fox4Kc
CNBC
Moderna stock jumped 3.8% following the announcement, with the company planning to engage with regulators on filing submissions for mRNA-1010 and present data at upcoming medical conferences.
Bloomberg.com
Investing
Investors
The results clear the path for Moderna's combination of COVID and flu vaccine, which the company voluntarily withdrew from the Food and Drug Administration (FDA) review in May to await these efficacy data from the standalone flu vaccine trial.
CNBC
BioSpace
Investors

Sources Split

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The Spin

Narrative A

This breakthrough represents a significant advancement in flu prevention technology. The mRNA platform offers superior precision in matching circulating strains, enabling rapid pandemic response capabilities. These results validate the potential for more effective seasonal vaccines during a time when flu hospitalizations reached 15-year highs.

StockTitan

Bloomberg.com

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Narrative B

Despite positive trial results, regulatory approval faces significant headwinds under the current administration. Health Secretary Robert F. Kennedy Jr. has restructured the vaccine advisory committees, which include known critics of mRNA, creating uncertainty around approval timelines. The new panel has already demonstrated reluctance to endorse mRNA technologies.

Reuters