During the past century, advances in hygiene, antibiotic development, and immunisations have resulted in cures for most childhood infections. Because access to medical care is not universally available, however, infectious diseases continue to be the main source of childhood mortality and morbidity. Increasingly, disparities in the health of children are linked to differences in socioeconomic status between industrialised and developing countries and between lower and higher income families within those countries. For example, diseases that are preventable by vaccination, such as polio, continue to flourish in parts of the world, and children are still becoming infected with HIV because identifying infected mothers and delivering effective drugs to them are formidable tasks.

In this review, we examine four prominent health issues influenced by social or economic conditions: vertical transmission of HIV, vaccines, obesity, and teenage smoking. The advances made in these areas are relevant to both industrialised and developing countries.