Moderna halted development of its cytomegalovirus vaccine mRNA‑1647 after a Phase III study missed the primary efficacy endpoint, delivering results well below company expectations. The failure intensifies near‑term pressure on Moderna’s respiratory and vaccine franchises and accelerates a strategic pivot toward cancer and rare‑disease programs, where the firm continues to present early clinical data. Analysts said the outcome reduces Moderna’s near‑term upside from vaccines but does not derail its longer‑term investment in mRNA‑based oncology candidates.