Moderna announced on Monday that its experimental mRNA-based flu vaccine demonstrated a significantly stronger immune response compared to the currently available vaccine during a late-stage clinical trial. This promising outcome paves the way for the advancement of both the flu vaccine and a combination vaccine targeting flu and Covid-19.
In May, Moderna had voluntarily withdrawn its application for approval of the combination vaccine, stating it intended to resubmit with updated efficacy data from the phase three trial of its standalone flu vaccine. The decision followed discussions with the Food and Drug Administration amidst ongoing major changes within the agency under Health and Human Services Secretary Robert F. Kennedy Jr., known for his skepticism towards vaccines.
With the new trial data, Moderna plans to refile for the combination vaccine approval as well as seek authorization for its standalone flu shot later this year. Stephen Hoge, the company’s head of research and development, expressed optimism in an interview about receiving approvals for both products next year, contingent on regulatory reviews.
Following this announcement, shares of Moderna rose more than 5% in premarket trading on Monday.
Hoge remarked that the combination vaccine would streamline the vaccination process, suggesting it will alleviate the workload for healthcare providers, reduce costs, and enhance patient uptake.
Currently, Moderna is in a competitive position against peers like Pfizer and Novavax in the race to market a combination vaccine. Although specific revenue projections for each product have not been disclosed, Hoge noted that the markets for Covid, flu, and respiratory syncytial virus vaccines each represent multi-billion-dollar opportunities.
“We certainly hope that our products will allow us to capture a fair share of those markets,” he stated.
The phase three trial involved over 40,000 adults aged 50 and older, who were randomly assigned to receive either a single dose of Moderna’s vaccine, known as mRNA-1010, or a standard competitor vaccine. The results indicated that Moderna’s shot was 26.6% more effective than its rival vaccine across the overall study population.
Additionally, the mRNA-1010 vaccine exhibited strong efficacy rates for several predominant influenza strains, including A/H1N1, A/H3N2, and the B/Victoria lineages. Moderna added that the benefits of the vaccine were consistent across various age demographics, risk categories, and previous flu vaccination statuses.
Among adults aged 65 and older, the efficacy of the Moderna shot was found to be 27.4% superior to the standard flu vaccine.
Moderna CEO Stephane Bancel described the efficacy results as a “significant milestone” in efforts to alleviate the impact of influenza among older adults. He highlighted that the severity of the previous flu season underlines the urgent need for more effective vaccines.
Moderna referenced data from the Centers for Disease Control and Prevention indicating that flu-related hospitalizations and outpatient visits reached their highest levels in 15 years during the 2024-2025 season. According to the CDC, over 600,000 Americans were hospitalized due to flu-related illnesses last year.
The safety data for the mRNA-1010 vaccine aligns with findings from a previous phase three study on the same product.
After experiencing a downturn of over 30% in their stock this year, partly due to shifting vaccine policies under the Trump administration— which included the cancellation of a contract for the development of a bird flu vaccine—Moderna faces a challenging regulatory landscape. In light of this, Hoge mentioned that the company is maintaining close engagement with the FDA to clarify and meet their requirements.
“Regarding the flu, I believe we’ve established a fairly clear path,” Hoge concluded.
