FDA Set to Review Moderna’s mFlusiva mRNA Flu Shot

An mRNA (messenger ribonucleic acid) influenza biologic developed by Moderna, Inc. is scheduled to be reviewed today by a U.S. Food and Drug Administration (FDA) advisory panel. The Vaccines and Related Biological Products Advisory Committee ((VRBPAC) will evaluate data on Moderna’s mFlusiva (formerly known as mRNA-1010) to determine if the product provides superior relative vaccine efficacy versus a standard-dose flu vaccine in ‌adults aged 50 to 64. It would vote on whether the benefits of mFlusiva outweigh the risks in adults 50 years and older.^{1 2 3 4}

Additionally, Moderna is seeking accelerated FDA approval of mFlusiva for adults 65 and older.²

A Reuters news release cites Jefferies Group financial analyst Andrew Tsai as saying he believes the assessment for mFlusiva looks “favorable.”²

Limitations in the Safety and Efficacy Data

However, there are limitations in the data for mFlusiva that may create roadblocks for a favorable decision on the product. For one, there is the fact that the biologic has only been studied during one influenza season. In an article for PharmExec.com, Nicholas Jacobus notes this “leav[es] open how the vaccine would perform against different circulating strains in future years.”^{2 5}

Another limitation in the data is that immunocompromised individuals and very frail older adults were not included in the clinical trials for the product—two groups which Jacobus points out are at the “highest absolute risk of severe flu-related complications and those most likely to respond differently to mRNA-based vaccine platforms.”^{2 5}

Also, the accelerated approval application for mFlusiva for those 65 and older is based on immunogenicity data for the shot ‌against a ​standard-dose flu shot, rather than high-dose, recombinant, or adjuvanted influenza vaccines preferred by the U.S. Centers for Disease Control and Prevention (CDC).^{2 5}

Lastly, there is the problem of a lack of data on co-administration of mFlusiva with other routinely recommended respiratory vaccines such as COVID-19, RSV (Respiratory Syncytial Virus), and pneumococcal vaccines. No safety studies have been done on the health impacts of administering mFlusiva to patients who have also received one or more of the other shots.⁵

FDA scientists who have reviewed the data for mFlusiva have reportedly highlighted that these limitations “lower the applicability of the efficacy data to a substantial portion of the intended patient population.”⁵

mFlusiva Could Be the First mRNA Flu Shot

A decision by the FDA on mFlusiva is expected to be made by Aug. 5, 2026. If the licensure application for the experimental biologic is approved, it would make mFlusiva the the first mRNA-based seasonal flu shot in the United States.^{2 5}

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