MMR vaccine and idiopathic thrombocytopaenic purpura
Article first published online: 14 JAN 2003
British Journal of Clinical Pharmacology
Volume 55, Issue 1, pages 107–111, January 2003
How to Cite
Black, C., Kaye, J. A. and Jick, H. (2003), MMR vaccine and idiopathic thrombocytopaenic purpura. British Journal of Clinical Pharmacology, 55: 107–111. doi: 10.1046/j.1365-2125.2003.01790.x
- Issue published online: 14 JAN 2003
- Article first published online: 14 JAN 2003
- Received 17 April 2002, accepted 13 August 2002.
- idiopathic thrombocytopaenic purpura;
- MMR vaccine
Aims To estimate the relationship between idiopathic thrombocytopaenic purpura (ITP) and the measles, mumps and rubella (MMR) vaccination in children; calculating the relative risk estimate for ITP with in 6 weeks after MMR vaccination and the attributable risk of ITP within 6 weeks after MMR vaccination.
Methods Using the General Practice Research Database we identified children with a first-time diagnosis of ITP from a base population of children aged less than 6 years between January 1988 and December 1999. After describing the characteristics of all the children identified with ITP, we focused on cases aged 13–24 months to perform a population-based, case–control analysis to estimate the relative risk of developing ITP within 6 weeks after MMR vaccination. We also calculated the risk of ITP attributable to the MMR vaccination.
Results Sixty-three children with a first time diagnosis of ITP were identified; 23 cases were between 13 and 24 months old. The relative risk estimate for ITP within 6 weeks after MMR vaccination, compared to the combined group of unvaccinated children and children vaccinated with MMR more than 26 weeks previously was 6.3 (95% CI 1.3–30.1). The attributable risk of developing ITP within 6 weeks after MMR vaccination was estimated to be 1 in 25 000 vaccinations (95% confidence interval 21 300, 89 400).
Conclusion This study confirms the increased risk of ITP within 6 weeks after MMR vaccination. However, the attributable risk of ITP within 6 weeks after MMR vaccination is low.