The FDA rejected Moderna’s mRNA flu shot, then quietly reversed course days later

The Food and Drug Administration has reversed its earlier decision and will now review Moderna’s application for a new mRNA flu vaccine. As first reported by The New York Times, the agency had initially refused to accept the company’s filing, citing concerns about the design of its clinical research.

That rejection surprised investors and industry leaders, particularly because the FDA had previously signaled that Moderna’s study framework was acceptable. Days later, after discussions between the company and regulators, the agency agreed to move forward with a formal review.

Under the revised plan, Moderna will split its application by age group. Seeking standard approval for adults 50 to 64 and accelerated approval for those 65 and older.

The agency’s sudden reversal has intensified scrutiny of its vaccine oversight

The initial refusal had sparked concern across the pharmaceutical sector, especially given the significant investment behind the vaccine’s development. The FDA has not publicly detailed why it changed course. However, the decision followed industry criticism and internal disagreement within the agency.

The episode reflects broader tensions between drugmakers and federal regulators. Executives have met with President Donald Trump to discuss tariffs and drug pricing, and the political focus has also included a Trump tax loophole pledge.

Dr. Stephen Hoge, Moderna’s president, said companies need clear and consistent rules from regulators. He warned against what he characterized as arbitrary changes after clinical trials have already been completed.

The dispute comes as the Trump administration has taken a more skeptical stance toward mRNA technology, despite supporting mRNA based Covid vaccines during Trump’s first term. That shift has led to canceled research contracts and narrower Covid vaccine recommendations under Health Secretary Robert F. Kennedy Jr., and separate tech debates have included Andrew Yang’s AI layoff warning.

The FDA’s initial rejection letter, signed by Dr. Vinay Prasad, cited concerns that Moderna used a standard-dose flu vaccine as its control for adults over 65 instead of a higher-dose option typically recommended for older patients. The decision reportedly overruled the agency’s second-highest-ranking vaccine scientist.

Following backlash, FDA Commissioner Dr. Marty Makary said the company could re-engage through the agency’s normal review process. Andrew Nixon, a spokesman for the Department of Health and Human Services, confirmed that subsequent meetings led to acceptance of Moderna’s revised plan, adding that the FDA would maintain its standards.

Moderna said the FDA had previously deemed its plan to use Fluarix Quadrivalent, a widely distributed vaccine made by GSK, acceptable for the clinical trial. The company reported that its mRNA flu shot was safe and effective across age groups, though side effects such as fatigue, muscle pain, headache, and injection site pain were more common among adults under 65 and more frequent than with the comparison vaccine.

John F. Crowley, president of the Biotechnology Innovation Organization, said the reversal underscores the importance of consistency in regulation and described mRNA development as critical to public health. The FDA has set an August deadline for its decision. If approved, the vaccine could become available to older adults in time for the upcoming flu season.