RESUMEN
Background: Vaccination is an essential component of the public health programs and among most cost effective medical intervention. Vaccines like other pharmaceutical product are not entirely risk free; while most known side effects are mild and non-serious. But some vaccines have been associated with very rare but serious side effect. So, there is a need of a surveillance program to monitor and record such events. Aims & Objective: To detect adverse events following immunizations (AEFI) in children and find vaccine responsible for them. Material and Methods: A one year, prospective, vaccine safety study was undertaken in 2011 covering a pediatric population who were administered vaccines. A two-phase telephone survey of all patients was conducted, comprising of an initial call at 1 week and a follow-up call at 30 days after the vaccine administration date. All AEFI were recorded in Vaccine Adverse Event Reporting System (VAERS) form. Results: Of a total sample of 4320 children, ranging in age from 0 to 14 years, 10110 vaccine doses were given. Each child received 2.34 vaccines on an average. Out of 4320 children, 899 children (20.8%) suffered 1003 AEFI. The most frequent types of adverse reactions to vaccines were fever (34.33 per 1000 doses), excessive crying (30.95 per 1000 doses) and injection site swelling (18.57 per 1000 doses). AEFI rate per 1000 doses was 99.2%. Conclusion: Most of the adverse events reported were mild and non-serious. Establishment of national AEFI database can be a worthy long term goal in Indian context.