Measles-mumps-rubella vaccine: ITP-MMR. Acute ITP occurs after vaccinations against several infectious agents. Best studied is measles-mumps-rubella (MMR) vaccination, but there is reasonable documentation for acute thrombocytopenia developing after vaccination against pneumococcus, Haemophilus influenzae B, hepatitis B virus, and varicella-zoster virus (VZV).
The estimated incidence of ITP-MMR is 1 in 40 000 doses, defined as thrombocytopenia developing within 42 days of exposure, an incidence 6-fold higher than acute ITP of childhood. Most cases occur after initial vaccination during the second year of life, and there is a male predominance. Thrombocytopenia is often severe, but responsive to IVIG or corticosteroids. More than 80% recover within 2 months, typically within 2 to 3 weeks, with less than 10% evolving into chronic ITP, simulating the pattern of acute ITP of childhood. The pathophysiology is unknown, although antibodies to GPIIb/IIIa have been identified in few patients, similar to primary ITP. Patients in remission or with stable ITP may receive all recommended immunizations, as the incidence of ITP-MMR is 10- to 20-fold lower than after natural infection. Delays in vaccination are appropriate during resolution of acute ITP or immunosuppressive treatment. The Centers for Disease Control Advisory Committee on Immunization Practices has recommended assessing immunity to determine the need for revaccination, although recurrence of thrombocytopenia after revaccination is rare.
bloodjournal.hematologylibrary.org/cgi/content/full/113/26/6511?maxtoshow=&hits=10&RESULTFORMAT=&fulltext=ITP+causes&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT