Incidence of Adverse Events Following Immunizations in Thailand 2008-2009

Abstract

This study aimed to delineate the incidence of adverse events following immunizations (AEFI) in Thailand. The data of patients from the monitoring system, the investigation of adverse events following immunizations in Thailand during 2008-2009 and the information of the amount of each vaccine supplied, were reviewed and analyzed. The results revealed that proportions of having adverse events in less than one year old group were the highest in both years (56.39%, 44.73%). In 2008, the most proportion of vaccine was OPV vaccine (32.0%), followed by DTP-HB vaccine (23.78%) and DTP Vaccine (17.44%) while in 2009, the most one was DTP-HB vaccine (23.78%), followed by OPV vaccine (31.23%) and JE vaccine (10.46%). In 2008, the top 3 orders incidence of adverse events per 100,000 doses were found in DTP-HB vaccine (6.04), DTP vaccine (4.46) and Influenza vaccine (3.27) while in 2009, those was found in DTP-HB vaccine (11.18), Influenza vaccine (9.32) and JE vaccine (7.34). According to the causes of adverse events following immunizations during 2008-2009, more than half of causes were related to the vaccines. Most symptoms of adverse events were fever and febrile seizure. The diagnosis of the adverse events following immunizations should be emphasized. The reporting and investigating all cases with adverse events should be strengthened and the finding should be applied to improve the quality of immunization service.