The agency requires more data to prove efficacy for over 65s, but has licensed the first mRNA-based flu shot in the United States for those aged 50-64.

The clearance paves the way for the first preventive flu shot based on mRNA technology and completes a dramatic regulatory turnaround.

The FDA’s approval is welcome news, and will hopefully open the door to much faster production of an effective vaccine to counter any future flu pandemic.

The vaccine, developed by Moderna, is approved for adults ages 50 to 64 and those 65 and older, who face the highest risk of severe illness.