Surveillance of Events Supposedly Attributable to Vaccination or Immunization (ESAVI) Linked to the Pandemic Influenza (H1N1) 2009 Vaccine and Crisis Prevention: Field Guide

Abstract

The prevention of infectious disease through immunization is one of the greatest achievements of public health. In spite of this undeniable success story, immunization is not immune from controversy surrounding the occurrence of a severe or fatal clinical event or series of events that, because they are temporally associated with vaccination, cause the public to lose confidence in vaccines and health services. Moreover, as immunopreventable diseases become less visible due to the decrease or disappearance in cases, as a result of effective immunization programs, adverse reactions to vaccines become more evident and the positive risk/benefit ratio that this implies is questioned. The mitigation phase of the pandemic from pandemic influenza (H1N1) 2009 involved the implementation of prevention and control measures, including vaccination. New technologies and new potentiators (adjuvants) of immunological response have been used for production of the pandemic vaccine to increase its availability, which was quite limited in the initial production phase. Pandemic vaccination is targeted to the at-risk population (the chronically ill, pregnant women, etc.) and the occurrence of a serious or severe event temporally associated with vaccination or rumors could ignite an unforeseen public health crisis that, if not handled properly, could cause the achievements made from immunization to be lost or questioned. This Field Guide for the Surveillance of Events Supposedly Attributable to Vaccination or Immunization (ESAVIs) Linked to the Pandemic Influenza (H1N1) 2009 Vaccine and Crisis Prevention provides health workers with key technical information necessary for reporting, complete epidemiological investigation, and final case classification, as well as for honest communication with the public through the mass media. Most of the information contained in this guide comes from technical articles and manuals on vaccination safety previously produced by the Pan American Health Organization (PAHO). Reports from Technical Committees on Immunization and other publications and documents were also consulted, which are listed in the references.