
Background: Immunization programme is an important determinant of the health status in a region. Full awareness regarding usefulness and safety of vaccines are required. Proper evaluation of vaccine related adverse events are essential. Objective of study was to analyze pattern of Adverse Events Following Immunization (AEFI) in children below 12 years of age. Methods: Observational prospective study was carried out in the Department of Paediatrics, Gauhati Medical College & Hospital, Guwahati, where children receiving routine immunization were analyzed & followed up through telephonic survey of parents. Vaccine Adverse Event Reporting System (VAERS) form was used to record AEFI. Results: Total 1378 children received total of 3361 vaccine doses. 17.7% AEFI were reported. Most common AEFI per 1000 doses of all vaccinations was Fever. DPT vaccine was most common vaccine associated with AEFI. Conclusions: Strengthening of AEFI reporting and assessment is essential for improving immunization coverage.