Medical Health Encyclopedia

Interaction with Tuberculosis Test. The live-measles vaccine may interfere with a tuberculosis test, so the two should be administered at least four to six weeks apart. No evidence exists that the vaccine has an adverse effect on tuberculosis itself.

Mild Infection. One study suggests that a mild form of measles that has no symptoms may develop in previously immunized people who are exposed to the virus, although this mild infection may not be significant.

Idiopathic Thrombocytopenic Purpura (ITP). In about one in 22,300 doses, MMR can cause a rare bleeding disorder called idiopathic thrombocytopenic purpura (ITP). This can cause a purple bruise-like discolorations that can spread across the body, nose bleeds, or tiny red spots. It is nearly always mild and temporary. (Of note, the risk for ITP is much higher with the actual infections, particularly rubella.)

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Note: Unsubstantiated Reports of Neurologic Side Effects and Decline in Immunization. Much controversy has arisen over unsubstantiated reports of neurologic side effects attributable to MMR. This is of great concern since such reports have resulted in a decline in immunizations in certain areas, notably affluent areas in England where the vaccination rate has dropped from 92% in 1996 to 84% currently. Here, measles outbreaks are now climbing and experts fear that unless immunization rates increase rapidly, case numbers will significant increase. In these and other regions, some parents mistakenly believe that the dangers of immunization outweigh a dangerous childhood illness that only older people remember. It should be strongly noted that measles still cause about 745,000 deaths in unvaccinated children who live in underdeveloped countries, mostly Africa.

Most publicity has centered on a possible link between the MMR vaccine, which was introduced in 1988, and a variant of autism that includes inflammatory bowel disease (IBD) and impaired behavioral development. Such findings have been rigorously reviewed and refuted in a number of well-conducted studies. Of special note, a 2002 analysis of vaccination records of children born between 1979 and 1998 found no higher incidence in autism, with or without behavioral problems and gastrointestinal disorders. In the study, there was a link between impaired behavioral development and bowel problems, but they were not related to the vaccine.