The US Department of Health and Human Services is terminating a contract with drugmaker Moderna to develop a vaccine to protect against bird flu amid the agency’s broader efforts to reevaluate therapies that use mRNA technology.

The Trump administration has canceled $766 million awarded to drugmaker Moderna Inc. to develop a vaccine against potential pandemic influenza viruses, including H5N1 bird flu

The department cited Moderna’s use of the messenger RNA technology, which it said “remains under-tested,” for the cancellation of the funding.