Moderna Announces Positive Phase 3 Results for Seasonal Influenza Vaccine

Rhea-AI Summary

Moderna (NASDAQ:MRNA) has announced positive Phase 3 results for its seasonal influenza vaccine candidate mRNA-1010. The vaccine demonstrated 26.6% superior relative vaccine efficacy (95% CI; 16.7%, 35.4%) compared to a licensed standard-dose seasonal influenza vaccine in adults aged 50 years and older.

The study showed strong relative vaccine efficacy across all influenza strains: 29.6% for A/H1N1, 22.2% for A/H3N2, and 29.1% for B/Victoria lineages. In participants aged 65 and older, mRNA-1010 achieved a 27.4% relative vaccine efficacy. The Phase 3 trial (P304) enrolled 40,805 adults across 11 countries, with a median follow-up of six months.

Safety and tolerability profiles were consistent with previous studies, with most solicited adverse reactions being mild. The most common local reaction was injection site pain, while fatigue, headache, and myalgia were the most common systemic reactions. Moderna plans to present the data at an upcoming medical conference and engage with regulators for submissions.

Positive

• Superior relative vaccine efficacy of 26.6% compared to standard-dose seasonal influenza vaccine
• Strong efficacy demonstrated across all influenza strains (A/H1N1: 29.6%, A/H3N2: 22.2%, B/Victoria: 29.1%)
• Consistent efficacy across age groups, risk factors, and previous vaccination status
• Large-scale Phase 3 trial with 40,805 participants validates results
• Favorable safety profile with mostly mild adverse reactions

Negative

• Injection site pain and systemic adverse reactions (fatigue, headache, myalgia) reported as common side effects

Insights

Pharmaceutical Analyst

Moderna's flu vaccine shows 26.6% higher efficacy than standard vaccines, positioning it for potential market disruption in the $7B+ influenza market.

Moderna's mRNA-1010 flu vaccine has achieved a significant clinical milestone by demonstrating 26.6% superior relative vaccine efficacy compared to standard-dose vaccines in older adults. This represents a breakthrough in influenza prevention, as current vaccines typically offer only 40-60% effectiveness. The consistent efficacy across all targeted strains (A/H1N1 at 29.6%, A/H3N2 at 22.2%, and B/Victoria at 29.1%) demonstrates the mRNA platform's versatility.

Particularly noteworthy is the 27.4% higher efficacy in adults 65+ - a population especially vulnerable to influenza complications yet typically showing reduced response to conventional vaccines. The successful Phase 3 trial involving 40,805 participants across 11 countries provides robust evidence for regulatory submissions.

The timing is opportune, following a severe 2024-2025 flu season with 600,000+ hospitalizations. The mRNA platform's ability to precisely match circulating strains addresses a fundamental limitation of egg-based vaccine production, which requires months of lead time and risks mutation during production. This technology could potentially enable more responsive updates to match emerging strains and create combination vaccines with COVID-19 protection.

The safety profile remains consistent with previous findings, showing predominantly mild adverse reactions similar to other mRNA vaccines. With these strong results, Moderna appears well-positioned to disrupt the $7+ billion global influenza vaccine market currently dominated by Sanofi, GSK, and CSL Seqirus.

mRNA-1010 demonstrated superior relative vaccine efficacy that was 26.6% (95% CI; 16.7%, 35.4%) higher than a licensed standard-dose seasonal influenza vaccine in adults aged 50 years and older

CAMBRIDGE, MA / ACCESS Newswire / June 30, 2025 / Moderna, Inc. (NASDAQ:MRNA) today announced positive results from a Phase 3 efficacy study (P304) evaluating the relative vaccine efficacy (rVE) against influenza illness of mRNA-1010, the Company's seasonal influenza (flu) vaccine candidate, compared to a licensed standard-dose seasonal influenza vaccine in adults aged 50 years and older. mRNA-1010 achieved the most stringent superiority criterion prespecified in the protocol, with an rVE of 26.6% (95% CI; 16.7%, 35.4%) in the overall study population. Additionally, strong rVE was observed for each influenza strain contained in the vaccine, including A/H1N1 (rVE=29.6%), A/H3N2 (rVE=22.2%), and the B/Victoria lineages (rVE=29.1%). Subgroup analyses confirmed a consistently strong rVE point estimate across age groups, risk factors and previous influenza vaccination status. In participants aged 65 years and older, mRNA-1010 demonstrated an rVE of 27.4%.

"Today's strong Phase 3 efficacy results are a significant milestone in our effort to reduce the burden of influenza in older adults. The severity of this past flu season underscores the need for more effective vaccines," said Stéphane Bancel, Chief Executive Officer of Moderna. "An mRNA-based flu vaccine has the potential advantage to more precisely match circulating strains, support rapid response in a future influenza pandemic, and pave the way for COVID-19 combination vaccines."

In a previous Phase 3 study, mRNA-1010 had already demonstrated superior seroconversion rates and geometric mean titer ratios (GMR) against all strains included in the vaccine compared to both high-dose and standard-dose licensed seasonal influenza vaccine. ^[1]

According to the CDC, seasonal flu-related hospitalizations and outpatient visits reached a 15-year high during the 2024-2025 season. ^[2] More than 600,000 Americans were hospitalized due to flu-related illness last year, leading to substantial direct and indirect costs, as well as widespread disruption to daily life and work. ^[3]

P304 ( NCT06602024 ) is a Phase 3, randomized, observer-blind, active-controlled, case-driven, pivotal efficacy, immunogenicity and safety study. The trial enrolled 40,805 adults aged 50 years and older across 11 countries. Participants were randomly assigned to receive either a single dose of mRNA-1010 or a standard-dose licensed comparator, with a median follow-up of six months.

Safety and tolerability of mRNA-1010 were consistent with reported results from a previous Phase 3 study. ^[4] The majority of solicited adverse reactions (SARs) were mild. Injection site pain was the most common local SAR, and fatigue, headache and myalgia were the most common systemic SARs reported. There were no significant differences between the groups in the rates of unsolicited adverse events, serious adverse events, or adverse events of special interest.

Moderna plans to present these data at an upcoming medical conference and submit for peer-reviewed publication. The Company will engage with regulators on filing submissions for mRNA-1010.

About Moderna

Moderna is a leader in the creation of the field of mRNA medicine. Through the advancement of mRNA technology, Moderna is reimagining how medicines are made and transforming how we treat and prevent disease for everyone. By working at the intersection of science, technology and health for more than a decade, the company has developed medicines at unprecedented speed and efficiency, including one of the earliest and most effective COVID-19 vaccines.


Moderna's mRNA platform has enabled the development of therapeutics and vaccines for infectious diseases, immuno-oncology, rare diseases and autoimmune diseases. With a unique culture and a global team driven by the Moderna values and mindsets to responsibly change the future of human health, Moderna strives to deliver the greatest possible impact to people through mRNA medicines. For more information about Moderna, please visit modernatx.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including statements regarding: Moderna's engagement with regulators on filing submissions for its standalone flu vaccine candidate; and the efficacy, safety and tolerability of mRNA-1010. The forward-looking statements in this press release are neither promises nor guarantees, and you should not place undue reliance on these forward-looking statements because they involve known and unknown risks, uncertainties, and other factors, many of which are beyond Moderna's control and which could cause actual results to differ materially from those expressed or implied by these forward-looking statements. These risks, uncertainties, and other factors include, among others, those risks and uncertainties described under the heading "Risk Factors" in Moderna's Annual Report on Form 10-K for the fiscal year ended December 31, 2024, and in subsequent filings made by Moderna with the U.S. Securities and Exchange Commission, which are available on the SEC's website at www.sec.gov . Except as required by law, Moderna disclaims any intention or responsibility for updating or revising any forward-looking statements contained in this press release in the event of new information, future developments or otherwise. These forward-looking statements are based on Moderna's current expectations and speak only as of the date of this press release.

Moderna Contacts

Media:

Chris Ridley
Head of Global Media Relations
+1 617-800-3651
Chris.Ridley@modernatx.com

Investors:

Lavina Talukdar
Senior Vice President & Head of Investor Relations
+1 617-209-5834
Lavina.Talukdar@modernatx.com

[1] https://pubmed.ncbi.nlm.nih.gov/39919447/

[2] https://www.cdc.gov/fluview/surveillance/2025-week-06.html

[3] https://www.cdc.gov/flu-burden/php/data-vis/2024-2025.html#:~:text=The%20estimates%20on%20this%20page,have%20ranged%20from%20120%2C000%2D710%2C000

[4] https://pubmed.ncbi.nlm.nih.gov/39919447/

SOURCE: Moderna, Inc.

View the original press release on ACCESS Newswire

FAQ

What were the Phase 3 results for Moderna's flu vaccine mRNA-1010?

Moderna's mRNA-1010 demonstrated 26.6% superior relative vaccine efficacy compared to standard flu vaccines in adults 50 and older, with strong efficacy across all influenza strains.

How effective is Moderna's mRNA-1010 flu vaccine in elderly adults?

In adults aged 65 and older, mRNA-1010 showed a 27.4% relative vaccine efficacy compared to standard flu vaccines.

What are the side effects of Moderna's new flu vaccine mRNA-1010?

Most side effects were mild, with injection site pain being the most common local reaction, and fatigue, headache, and myalgia being the most common systemic reactions.

How many participants were in Moderna's mRNA-1010 Phase 3 trial?

The Phase 3 trial enrolled 40,805 adults aged 50 years and older across 11 countries, with a six-month median follow-up period.

What is the efficacy of mRNA-1010 against different flu strains?

The vaccine showed strong efficacy across all strains: 29.6% for A/H1N1, 22.2% for A/H3N2, and 29.1% for B/Victoria lineages.