Guidance

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

Information for public health professionals about how vaccines work.

• From: UK Health Security Agency
• Published: 19 March 2013
• Last updated: 5 January 2021 — See all updates

Documents

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

Ref: PHE publications gateway number 2020417

PDF, 60 KB, 8 pages

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Details

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. 5 January 2021

   Updated links to Academy for life and the porcine gelatine leaflet.

2. 16 December 2020

   Added updated Greenbook chapter 1.

3. 19 December 2018

   Updated with new 'green book' formatting.

4. 19 March 2013

   First published.