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.

HHS has notified Moderna that it is canceling a nearly $600 million contract for vaccines for flu strains that could trigger future pandemics.

With the continued use of COVID-19 vaccines worldwide, there’s a massive amount of data that shows mRNA shots are safe.