Use of the Australian Childhood Immunisation Register for vaccine safety data linkage.

We linked the Australian Childhood Immunisation Register (ACIR) to South Australian (SA) hospital outcome data in order to evaluate the association between Measles Mumps and Rubella (MMR) and Diphtheria Tetanus Pertussis (DTP) vaccines and convulsions. Linkage occurred using probabilistic matching and data was analysed using the self-controlled case series methodology. An increase in febrile convulsions 6-11 days post-MMR vaccination was demonstrated which equates to a vaccine-attributable risk of 1 convulsion per 6753 vaccines. This study confirms the known association between MMR vaccination and febrile convulsions and in doing so demonstrates the feasibility of using the ACIR for data linkage and vaccine safety surveillance.