The U.S. Department of Health and Human Services said it is winding down federal development of messenger-RNA vaccines and cancelling 22 contracts and solicitations worth about $500 million. The move, announced late Tuesday by Health Secretary Robert F. Kennedy Jr., affects projects overseen by the Biomedical Advanced Research and Development Authority, including a late-stage H5N1 bird-flu shot from Moderna and proposals from Pfizer, Sanofi Pasteur, CSL Seqirus and others. Kennedy argued that data show existing mRNA shots “fail to protect effectively against upper respiratory infections like Covid and flu,” and said the money will be redirected to whole-virus and other vaccine approaches he described as safer and more resistant to viral mutation. Other government work with mRNA platforms, such as cancer therapeutics, is not included in the cut-back, according to HHS. Infectious-disease specialists and security analysts swiftly condemned the decision, noting that mRNA vaccines were central to Operation Warp Speed and are credited with saving millions of lives during the pandemic. Critics warned the United States is relinquishing one of its fastest tools for responding to new pathogens, creating what one analyst called a “national security vulnerability.” The cancellation continues a broader restructuring of health policy under the second Trump administration, reflecting Kennedy’s long-standing skepticism toward mRNA technology. Industry executives said the abrupt reversal could delay next-generation vaccines, while smaller biotechnology firms reliant on BARDA support may be forced to shelve or scale back research.