MMR vaccine & ASD (AUTISM) IS IT true or a myth

INFORMATION FOR PATIENTS

UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or email these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient education" and the keyword[s] of interest.)

●Beyond the Basics topics (see "Patient education: Why does my child need vaccines? (Beyond the Basics)" and "Patient education: Autism spectrum disorder (Beyond the Basics)")

SUMMARY

●Apparent increased in ASD – The prevalence of autism spectrum disorder (ASD) appears to have increased since the 1980s. Much of this trend is accounted for by changes in the case definition and increased awareness of ASD. Whether the actual incidence of autism has increased is unclear. (See 'Apparent increased prevalence of autism spectrum disorder' above.)

●Proposed association between vaccines and ASD – The real or perceived increase in ASD cases occurred at a time when the number of recommended childhood vaccines also increased. Caregivers of children with ASD and some professionals identified a temporal association between immunizations and the onset of more evident symptoms of ASD in the second year of life, leading to speculation that certain vaccines or vaccine constituents may play a role in the development of ASD. (See 'Proposed association between vaccines and ASD' above.)

●Lack of evidence of an association – Multiple large, well-designed epidemiologic studies and systematic reviews do not support an association between the measles, mumps, and rubella vaccine and ASD. (See 'Lack of evidence for association' above.)

Similarly, multiple large, well-designed epidemiologic studies and systematic reviews do not support an association between thimerosal and ASD. (See 'Lack of evidence for association' above.)

●Proven benefits of vaccines and consequences of vaccine refusal – The administration of childhood vaccines has led to a decline in the incidence of childhood diseases that can have severe sequelae (figure 1). (See 'Proven benefits of vaccines' above.)

Withholding vaccines from a child because of a hypothetical risk places the child at risk for real infection that may have real sequelae. (See "Standard childhood vaccines: Caregiver hesitancy or refusal", section on 'Consequences of vaccine refusal'.)

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