A collaborative approach to investigating the risk of thrombocytopenic purpura after measles-mumps-rubella vaccination in England and Denmark

► Vaccine safety assessment is being established across Europe within the VAESCO consortium. ► Collaborative issued were identified in this study of TP following MMR in England and Denmark. ► The two countries obtained similar relative incidence estimates of about 2 in the 6 weeks post vaccination. ► This equates to an attributable risk of 1 TP per 50,000 doses. ► The self controlled case series method used is particularly suited to collaborative studies.