Validation of the French national health insurance information system as a tool in vaccine safety assessment: Application to febrile convulsions after pediatric measles/mumps/rubella immunization

In the French national health insurance information system (SNIIR-AM), routine records of health claimed reimbursements are linked to hospital admissions for the whole French population. The main focus of this work is the usability of this system for vaccine safety assessment programme. Self-controlled case series analyses were performed using an exhaustive SNIIR-AM extraction of French children aged less than 3 years, to investigate the relationship between MMR immunization and children hospitalizations for febrile convulsions, a well-documented rare adverse event, over 2009-2010. The results suggest a significant increase of febrile convulsions during the 6-11 days period following any MMR immunization (IRR = 1.49, 95% CI = 1.22, 1.83; p = 0.0001) and no increase 15-35 days post any MMR immunization (IRR = 1.03, 95% CI = 0.89, 1.18; p = 0.72). These results are in accordance with other results obtained from large epidemiologic studies, which suggest the usability of the SNIIR-AM as a relevant database to study the occurrence of adverse events associated with immunization. For future use, results associated with risk of convulsion during the day of vaccination should nevertheless be considered with particular caution.