The history of immunology spans centuries, beginning with variolation practices in Ancient China. Edward Jenner furthered this field by creating the smallpox vaccine, while Louis Pasteur's germ theory significantly enhanced the understanding of infectious diseases. Paul Ehrlich's side-chain theory and the discovery of antibodies facilitated the understanding of the immune system's defense mechanisms. The 20th and 21st centuries saw immunology advancements through the discovery of the immune system's memory and complex immune response components, contributing to vaccine development and immunotherapies.

Infectious diseases have greatly impacted historical events, often changing their outcomes. Widespread diseases during wars, like the Napoleonic Wars and World War I, led to more deaths than actual combat. In the era of slavery and colonialism, Europeans inadvertently spread diseases among indigenous populations, causing devastation that facilitated colonial dominance. In modern times, the HIV/AIDS pandemic has notably influenced socio-political situations in sub-Saharan Africa.

The understanding of infectious diseases has evolved from ancient attributions to gods' displeasure, through Hippocrates' humoral theory in Ancient Greece, and Galen's development of it in Rome, to important advances during the Islamic Golden Age. The devastating Black Death led to theories on disease contagion, laying foundations for the 17th century's microscopic observations and the subsequent germ theory that revolutionized modern microbiology.