The Department of Health and Human Services will cancel contracts and pull funding for some vaccines that are being developed to fight respiratory viruses like COVID-19 and the flu.

Robert F. Kennedy Jr., the health secretary and a longtime vaccine critic, announced in a statement Tuesday that $500 million worth of vaccine development projects, all using mRNA technology, will be halted.

“We reviewed the science, listened to the experts, and acted,” said HHS Secretary Robert F. Kennedy, Jr. “[The Biomedical Advanced Research and Development Authority] is terminating 22 mRNA vaccine development investments because the data show these vaccines fail to protect effectively against upper respiratory infections like COVID and flu. We’re shifting that funding toward safer, broader vaccine platforms that remain effective even as viruses mutate.”

The projects are being led by some of the nation’s leading pharmaceutical companies like Pfizer and Moderna to prevent flu, COVID-19 and H5N1 infections.

The mRNA vaccines are credited with slowing the 2020 coronavirus pandemic.

Kennedy said in the Tuesday statement that he wants the health department to move away from mRNA vaccines, calling on the department to start “investing in better solutions.” He provided no details on what those technologies might be.

“Let me be absolutely clear: HHS supports safe, effective vaccines for every American who wants them," he added.