The U.S. Department of Health and Human Services said Tuesday it is cancelling 22 messenger-RNA vaccine contracts and solicitations valued at almost $500 million, halting a slate of projects run through its Biomedical Advanced Research and Development Authority. Health Secretary Robert F. Kennedy Jr. said the contracts—which include late-stage work with Moderna, Pfizer, Sanofi Pasteur, CSL Seqirus, Gritstone and others—are being terminated because existing data show the shots “fail to protect effectively against upper respiratory infections like Covid-19 and flu.” Funding, he added, will be redirected to broader-spectrum or whole-virus platforms that HHS contends will hold up better as pathogens mutate. The decision represents the agency’s most sweeping retreat from mRNA technology since Operation Warp Speed and underscores a wider shift in vaccine policy under Kennedy, a long-time critic of the platform. Public-health and biodefence specialists warned the move could slow the nation’s ability to mount rapid immunisation campaigns in future outbreaks, given mRNA’s speed of manufacture. HHS said a handful of nearly completed awards—such as programmes at Arcturus and Amplitude—will run their course and emphasised that mRNA work pursued by the National Institutes of Health and the Department of Defense is unaffected.