Assess learners' understanding of how vaccines trigger innate and adaptive immune responses—covering innate sensing (PRRs, inflammation), antigen processing and presentation, B‑cell/antibody and T‑cell responses, and how mRNA, viral vector, inactivated, and protein subunit platforms differ in antigen delivery, innate activation/adjuvant effects, durability, safety profiles, and the balance of humoral versus cellular protection. Scope: conceptual mechanisms and platform comparisons for professional development.