HHS Secretary Robert F. Kennedy Jr. has canceled $500 million in funding for 22 research grants developing mRNA vaccines for viruses such as SARS-CoV-2 and influenza. This decision reverses previous government support of mRNA vaccine innovation despite substantial safety data and efficacy evidence. The termination focuses solely on vaccine research, not other mRNA therapies, but has triggered concern among scientists about potential setbacks in cutting-edge vaccine development capable of rapid responses to emerging pathogens.