Slight Risk of Bleeding Disorder No Reason to Avoid MMR Vaccine
The researchers also offer reassuring evidence that the vaccine does not appear to cause new ITP cases or reactivate ITP in children who have had the bleeding disorder before. In addition, the few cases of ITP that could be linked to the MMR vaccine appeared to be milder than others, they report.
"It confirms what was previously thought to be the case, which is that if you get the MMR [shot] you are at a low but real risk of developing idiopathic thrombocytopenic purpura within 6 weeks after the immunization," says Richard Malley, MD, assistant professor of pediatrics at Harvard Medical School and a staff physician in the division of infectious diseases at Children's Hospital, Boston.
Malley, who reviewed the study for WebMD, says that it confirms the benefits of immunization with MMR.
"If a parent thought, 'Well, I want to interpret these results as suggesting to me that I should not immunize my child because I don't want him to get ITP,' I would answer that, first of all, if you don't immunize the child, the risk is greater that he'll get a serious illness -- mostly measles, which is still around and has a lot more complications than just ITP," he explains. "But in addition, if the concern is mostly ITP, the risk ... for getting ITP should they get measles is significantly greater than [the risk of] getting ITP from MMR [vaccine]."
Despite persistent rumors to the contrary about vaccine safety, there is no credible scientific evidence to suggest that the MMR vaccine -- or any other vaccine, for that matter -- can cause autism, and although some people may object to immunization for religious or personal reasons, there is no solid medical ground under the feet of those who claim that childhood vaccines are unduly risky.
Miller says some rumors suggest that researchers are reluctant to reveal information on the adverse side effects of vaccines. "This paper shows that this is simply not the case -- we do extensive work on adverse reactions, and where we suspect that an adverse reaction occurs, we are committed to researching it, providing evidence about it, and making that evidence publicly available," she says in the written statement. "Equally, however, where the doubts are unfounded, as with the MMR and autism issue, we are committed to refuting those claims. We urge parents to protect their children against measles, mumps, and rubella with the MMR vaccine."