The move drew sharp criticism from medical and health experts. “Scrapping the fastest platform we have is a reckless move rooted in a fundamental misunderstanding of vaccinology,” wrote Jake Scott, an infectious diseases specialist and clinical associate professor of medicine at Stanford University, on the social media site Bluesky.

The Department of Health and Human Services said it is winding down its mRNA vaccine-development activities under the Biomedical Advanced Research and Development Authority.