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MMR vaccine and idiopathic thrombocytopaenic purpura
Author(s) -
Black Corri,
Kaye James A.,
Jick Hershel
Publication year - 2003
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1046/j.1365-2125.2003.01790.x
Subject(s) - medicine , vaccination , mmr vaccine , pediatrics , measles , relative risk , measles mumps rubella vaccine , rubella , confidence interval , population , attributable risk , rubella vaccine , immunology , environmental health
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.