Differences in health between groups are not distributed at random. They follow income, geography, race and the conditions in which people live and work, and the largest of them are produced by circumstances rather than by biology.
We report on how those differences are measured, what has been shown to narrow them, and where the measurement itself has been contested.
Global health explained: definition, how it differs from international and public health, key actors, financing, major priorities and persistent structural challenges.
How global immunization programs work: herd immunity, cold chain, delivery systems, WHO and Gavi roles, vaccine safety monitoring and barriers to coverage.
Health equity explained: what it means, how it differs from equality, social determinants of health, global and within-country disparities, and what actually works.