The UK CSM has recommended that patients who develop idiopathic thrombo-cytopenic purpura (ITP) within 6 weeks of receiving their first dose of measles, mumps and rubella (MMR) vaccine undergo a serological evaluation prior to receiving a second dose. The second dose is recommended where the patient is not fully immune against measles, mumps and rubella infections. These recommendations, which have been published on the website of the UK MCA, were made after the CSM reviewed all the available evidence on MMR vaccine and ITP. Particular attention was given to the risk/benefit balance associated with giving a second dose of MMR vaccine to patients who developed ITP within 6 weeks of their first dose of the vaccine. The MCA reports that, according to a recently published study, the absolute risk of developing ITP after receipt of a first MMR vaccination is 1/22 300 cases (with 2/3 ITP cases attributable to MMR vaccine); this is lower than the risk of developing ITP with wild measles (common) or rubella infections (1/3000 cases). The report also points out that the MMR vaccine product information is currently being revised to reflect the recommendations of the CSM.
Reports in WHO file: purpura thrombocytopenic 133
Current Problems in Pharmacovigilance 27: 15, Aug 2001.