The Food and Drug Administration on Wednesday approved Moderna’s mFlusiva, the first U.S. flu shot using mRNA technology, for adults 50 to 64 and 65 and older — with a required additional trial in the older group. In a late-stage study of more than 40,000 older adults across 11 countries, the shot was about 27% more effective than a standard flu vaccine, potentially giving clinicians a faster-to-update option ahead of this fall’s flu season.

The Move

• FDA cleared Moderna’s mFlusiva as the first U.S.-approved mRNA influenza vaccine.

• The approval covers adults ages 50 to 64 and adults 65 and older, but FDA required Moderna to run an added clinical trial in the 65-plus group.

• Moderna said the vaccine could be available for the coming flu season.

Why It Matters For Care

• For frontline clinicians, the key clinical takeaway is improved efficacy: mFlusiva was about 27% more effective than a standard flu shot in a late-stage trial.

• mRNA manufacturing can move faster than traditional egg- or cell-based flu vaccine production — roughly two to three months versus about six months — which could improve strain matching.

• Side effects including injection-site pain, fatigue and headache were more common than with standard flu shots, but were generally mild to moderate.

Between The Lines

• This approval lands despite Health and Human Services Secretary Robert F. Kennedy Jr.’s repeated criticism of mRNA technology and his department’s cancellation of nearly $500 million in mRNA research funding.

• FDA had briefly refused to review Moderna’s application before reversing course, reflecting internal scrutiny over whether the company compared its vaccine against the most appropriate comparator for adults 65 and older.

• The politics matter because regulatory clearance does not guarantee uptake: without CDC advisory backing, access and reimbursement could lag.

What To Watch

• The biggest near-term question is whether CDC’s Advisory Committee on Immunization Practices can meet after a federal judge blocked the panel from convening.

• Without an ACIP recommendation, clinicians could still prescribe the vaccine legally, but private insurance coverage, Medicaid pathways and broader federal distribution may be limited.

• Watch for Moderna’s required post-market study in older adults, any CDC guidance before peak vaccination season, and whether the company expands testing into additional age groups.

Source: NBC News Health