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Immunity and how vaccines work: the green book, chapter 1

Information for public health professionals about how vaccines work.

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Immunity and how vaccines work: the green book, chapter 1

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Immunity is the ability of the human body to protect itself from infectious disease. The defence mechanisms of the body are complex and include innate (non-specific, non-adaptive) mechanisms and acquired (specific, adaptive) systems.

Innate or non-specific immunity is present from birth and includes physical barriers (for example intact skin and mucous membranes), chemical barriers (for example gastric acid, digestive enzymes and bacteriostatic fatty acids of the skin), phagocytic cells and the complement system. Acquired immunity is generally specific to a single organism or to a group of closely related organisms. There are 2 basic mechanisms for acquiring immunity: active and passive.

Published 19 March 2013
Last updated 5 January 2021 + show all updates
  1. Updated links to Academy for life and the porcine gelatine leaflet.

  2. Added updated Greenbook chapter 1.

  3. Updated with new 'green book' formatting.

  4. First published.