Guidance

Vaccine safety and adverse events following immunisation: the green book, chapter 8

Information for public health professionals on immunisation.

• From: UK Health Security Agency
• Published: 20 March 2013
• Last updated: 9 July 2025
  Show all updates

  1. 9 July 2025

     Update to advice on the availability of oxygen and emphasis on space required for resuscitation.

  2. 22 November 2024

     Changes to Chapter 8, Vaccine safety and adverse events following immunisation - November 2024: Updates to the WHO definitions of adverse events following immunisation. Updates to immunisation error and vaccine product adverse event sections. New paragraphs defining anxiety related adverse events and vaccine product quality adverse events. Changes to managing common vaccine-induced AEFIs to include management fever following (Bexsero) 4CMenB vaccine administration. Changes to the section on thiomersal to clarify that this is no longer used in vaccines routinely administered to children. New section on hypotonic-hyporesponsive episodes following vaccination. Extensive re-write of the section on recognition and management of anaphylaxis. References updated.

  3. 20 March 2013

     First published.

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Vaccine safety and adverse events following immunisation: the green book, chapter 8

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Details

Vaccines induce protection by eliciting active immune responses to specific antigens. There may be predictable adverse reactions (side effects): most are mild and resolve quickly. However, it is not always possible to predict individuals who might have a mild or serious reaction to a vaccine. The advice in this chapter uses the World Health Organization (WHO) classification of adverse events following immunisation (AEFIs).