Global health is concerned with the health of all people on our planet, recognizing that the world is interconnected and that a health threat anywhere can become a threat everywhere. Hunter and Fineberg proposed a definition of global health as “public health for the world,”1 demanding further interrogation of what is public health. In an oft-cited report, the U.S. Institute of Medicine regarded public health as what society “does collectively to assure the conditions for people to be healthy,”2 a usefully comprehensive definition that can encompass clinical, preventive, and promotive as well as structural interventions to influence health in diverse contexts.
The philosophy of global health acknowledges the globalization of public health risks, not only the spread of infectious agents but also of other threats to public health such as tobacco use, consumption of sugar-laden drinks, unhealthy lifestyles promoting noncommunicable diseases (NCDs), unsafe or counterfeit medicines, and other factors undermining health.3 Specific threats such as infectious agents may spread more quickly today than in earlier times because of the increased extent and speed of travel; it is now possible to traverse the world within the incubation period of most infectious diseases.
Noninfectious agents such as unhealthy foods and drinks, legal and illicit drugs, and other toxic substances are commonly distributed through increasingly globalized supply chains and marketing strategies.4 Health is affected by the dissemination of ideas, behaviors, and cultural and recreational practices which reach and influence all corners of the world in an ever shorter time, spreading as effectively as infectious diseases. The Internet, social media, and other forms of modern communications have linked faraway places, just as air travel has bridged the physical distance that formerly kept them apart.
While global health is most definitively concerned with the well-being of our whole planet, it is also committed to health equity and concentrates much of its attention to more disadvantaged groups and areas. Encompassing priority populations, regions, and countries under a single term has proved problematic, not least because of dynamic socioeconomic development across the world. The term “Third World,” often used synonymously with the “developing world,” originated in the mid-twentieth century as a political concept describing countries not aligned with the First and Second Worlds, which referred, respectively, to nations affiliated to NATO or the communist Eastern Bloc. Recognition that poorer countries, described earlier as “underdeveloped and later as “developing,” were mostly found in the world’s southern hemisphere led to concepts of the “Global North” and “Global South” to indicate the rich and poor worlds.
All these terms have proved unsatisfactory and inconsistent over time with changes in the global landscape. The World Bank now usefully divides countries of the world into four categories based on Gross National Income per capita: high income; higher middle income; lower middle income; and low income. This categorization is reviewed annually, and countries can move ...