The US Food and Drug Administration (FDA) has approved Moderna's mRNA seasonal flu vaccine, mFlusiva (mRNA-1010), for adults aged 50 and over, after initially declining to even review the company's application. The approval matters because it marks the first mRNA flu jab to reach the market and follows a brief but politically charged dispute in which critics accused the FDA of blocking the vaccine for ideological rather than scientific reasons.

Moderna said the vaccine gained standard approval for those aged 50 to 64 following a Phase 3 trial involving 40,805 adults across 11 countries, and received accelerated approval for the over-65s. The company reported the jab was more effective than standard-dose licensed vaccines at preventing flu-like illness, though side effects such as injection-site pain, fatigue and headache were more common, typically mild and temporary. The FDA had originally rejected the trial's comparator vaccine as not meeting the "best available standard of care", a decision made after a political appointee overruled career scientists, before reversing course within a week once challenged on the inconsistency.