Every generation of global health depends on who was trained in the one before it. This week, the International Vaccine Institute marks 25 years of its flagship vaccinology course, gathering 200 professionals from 55 countries simultaneously in Seoul, Kigali, and Stockholm — a deliberate architecture of inclusion that reflects a hard-won understanding: pandemic preparedness cannot be built in wealthy nations alone. Under the theme of One Health, the course asks its participants to see human, animal, and environmental wellbeing not as separate domains, but as a single, fragile system worth defe