VACCINE ADVERSE EVENTS REPORTED DURING THE FIRST TEN YEARS (1998 to 2008) AFTER INTRODUCTION IN THE STATE OF RONDONIA, BRAZIL

Wednesday, 3rd of September 2014

[source]Biomed Research International[|source]

Vaccine safety surveillance and follow-up are central to address actual and perceived issues related to AEFI. However, such surveillance and follow-up infrastructure lags behind vaccine development in industrialized countries and is very weak in most developing countries.  AEFI systems are important tools to monitor temporal associations between vaccination and a suspected serious or mild adverse or unintended reaction to a given licensed product. The information collected can be used by government agencies in charge of public health, stakeholders, vaccine manufactures, scientists, and the general public assurances on the safety record of the products we use. Vaccine safety surveillance should (1) detect new, unusual, or rare vaccine adverse events; (2) monitor increases in known adverse events; (3) determine patient risk factors for particular types of adverse events; (4) identify vaccine lots with increased numbers or types of reported adverse events; and (5) assess the safety of newly licensed vaccines.

In this study, authors analyze and report on the notified adverse events in the state of Rondonia during the first ten years of the AEFI surveillance program implementation as a case study to address current safety issues related to vaccines used in children. The report concludes that there is a need to improve vigilance of vaccine adverse events before recommending that programs should implement compensation for those few children that are severely affected by unintended effects of vaccines. More details are accessible at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3586457/

 

ABSTRACT

Despite good safety records, vaccines given to young children can cause adverse events. We investigated the reported adverse events following immunization (AEFI) of vaccines given to children of less than seven years of age during the first ten years (1998 to 2008) in the state of Rondonia, Brazil. We worked with the events related to BCG (Bacillus Calmett-Guérin), HB (hepatitis B), DTwP/Hib (diphtheria-tetanus-pertussis+Hemophillus influenza b), DTP (diphtheria-tetanus-pertussis), MMR (mumps, measles, rubella), and YF (yellow fever) vaccines because they were part of the recommended scheme. The number of doses of vaccines given was 3,231,567 with an average of AEFI of 57.2/year during the studied period. DTwP/Hib was responsible for 298 (57.8%), DTP114 (22.9%), HB31 (6%), MMR28 (5.4%), BCG24 (4.7%), and YF20 (3.9%) of the reported AEFI. The combination of the AEFI for DTwP/Hib vaccines showed the highest number of systemic (61.4%) and local events (33.8%). Young children (≤1-year old) were more susceptible to AEFI occurring in the 6 hours (54.2%) following vaccine uptake. This study suggests significant differences in reactogenicity of vaccines and that despite limitations of the AEFI Brazilian registry system we cannot ignore underreporting and should use the system to expand our understanding of adverse events and effects.