In its inception in 1974, the Expanded Programme on Immunization (EPI) focused on protecting all children against 6 childhood illnesses. Still, today, this number has grown to 13 universally recommended vaccines across the life course, and 17 additional vaccines with context-dependent recommendations. In just 5 decades we went from a world where the death of a child was something many parents feared, to a world where every child - if vaccinated - has a chance to survive and thrive.