U.S. health officials are reevaluating a $590 million contract that was awarded to Moderna for the development of its bird flu vaccine, Bloomberg News reported on Wednesday, citing sources.

Shares of vaccine maker Moderna dropped more than 5% late Wednesday after reports that the Health and Human Services Department was re-evaluating its $590 million contract to develop a bird flu vaccine.

The Trump administration confirmed it's reviewing whether to pull $590 million in funding that Moderna received in the final days of the Biden administration to develop an mRNA vaccine for bird flu in people.