The U.S. Department of Health and Human Services (HHS) has canceled its $590 million agreement with Moderna for developing a bird flu vaccine, citing concerns over the scientific and ethical justification of further investment. This decision comes as part of a broader reassessment of mRNA-based treatments.

The canceled contract, announced in January ahead of President Trump’s second term, supported Moderna’s efforts to develop an H5N1 bird flu vaccine using mRNA technology. Moderna reported that early trials involving around 300 adults showed the vaccine triggered a strong and lasting immune response. Despite the loss of federal funding, Moderna CEO Stéphane Bancel affirmed the company’s commitment to exploring alternative ways to advance the program.

However, HHS stated that its review found the project lacking in terms of safety and scientific merit. “We will not repeat past mistakes,” said HHS Communications Director Andrew Nixon, referring to the Trump administration’s handling of similar issues.

mRNA technology, while successfully used in Covid-19 vaccines by both Moderna and Pfizer/BioNTech, remains under scrutiny. Public confidence has wavered due to growing anti-vaccine and anti-mRNA sentiment.

Experts, including Dr. Ashish Jha of Brown University, defended mRNA vaccines, calling criticisms unfounded. He warned that canceling the bird flu vaccine could jeopardize national health security if the virus becomes more contagious among humans.

H5N1 avian flu has infected and killed people in the U.S., though human cases have been absent for three months. Older vaccines are currently stockpiled but may not offer the rapid adaptability mRNA platforms provide.

Dr. Paul Friedrichs, former White House pandemic advisor, expressed disappointment over the decision, emphasizing the importance of preparedness and having vaccine options ready before a potential outbreak.