US HHS Secretary Robert F. Kennedy Jr. has canceled $500 million in funding for 22 mRNA vaccine projects, citing concerns over efficacy and safety, redirecting funds towards whole-virus vaccine platforms. This policy shift reverses previous strong government support for mRNA technology, which was instrumental during the COVID-19 pandemic. Experts criticize the move as potentially damaging innovation and public health efforts, noting the decision is based on selective and contested evidence. Some mRNA therapeutic research outside vaccines continues to receive funding.