This second edition which includes revised guidelines for managers of immunization programmes aims to assist managers in immunization programmes and national regulatory authorities to establish/strengthen immunization safety surveillance system. It provides guidelines for managers of immunization programmes and others responsible for vaccine safety and quality on the following: . strategies and systems for ensuring quality and safety of vaccines; . new classification of AEFIs and the objectives of immunization safety/AEFis surveillance; . understanding vaccine reactions for better decision-making; . AEFI surveillance system: reporting investigating causality assessment and responding processes; . best use of surveillance data and . communication strategy on immunization safety for the public and the media.