GC: n

S: WHO – http://www.who.int/topics/immunization/en/ (last access: 4 September 2014); WebMD – https://www.webmd.com/children/vaccines/immunizations-vaccines-power-of-preparation#1 (last access: 17 May 2020).

N: 1. 1893, from immunize (1889, from immune + -ize; related: Immunized; immunizing) + -ation (word-forming element for making nouns of action; see -ion).
2. Edward Jenner (1749-1823), after training in London and a period as an army surgeon, spent his whole career as a country doctor in his native county of Gloucestershire in the West of England. His research was based on careful case-studies and clinical observation more than a hundred years before scientists could explain the viruses themselves. So successful did his innovation prove that by 1840 the British government had banned alternative preventive treatments against smallpox. “Vaccination,” the word Jenner invented for his treatment (from the Latin vacca, a cow), was adopted by Pasteur for immunization against any disease.
3. Process by which resistance to disease is acquired or induced in plants and animals. This discussion focuses on immunization against infectious diseases in vertebrate animals, specifically humans.
Immunization may occur naturally, as when a person is exposed unintentionally to a pathogen (any infectious agent), or it may be brought about artificially through a vaccine. In either case, immunization provides resistance, or immunity, to a particular pathogen by means of antibody proteins that are targeted to eliminate that pathogen from the body.

S: 1. OED – http://www.etymonline.com/index.php?term=-ation&allowed_in_frame=0 (last access: 4 September 2014). 2. USC – http://library.sc.edu/spcoll/nathist/jenner.html (last access: 7 November 2013). 3. EncBrit (last access: 4 September 2014).

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CR: immune system, immunity.