A Possible Connection Between Autism and the MMR Vaccine?
You may have heard information in the news recently about a theoretical link between childhood vaccinations (specifically the vaccine for Measles, Mumps, and Rubella) and an increase in the number of children diagnosed with autism. This page is a synthesis of information from the Center of Disease Control and the Department of Health and Human Services about autism and the theory of an autism-vaccination link.
Information about Autism
The term autism refers to a collection of neurologically-based developmental disorder in which individuals have impairments of social interaction and communication skills, as well as a tendency to repeat behaviors. Autism is part of a group of disorders known as Autism Spectrum Disorders. There are several types of autism; the types show different kinds of symptoms, although individuals with various types may demonstrate some similar characteristics. Types of autism include: Asperger’s syndrome, autistic disorder, pervasive developmental disorder. It was first identified as a specific disorder by Dr. Leo Kenner in 1943.
To date, there is no known cause of autism. However, there are several factors that tend to correlate with higher rates of autism. Boys are four times more likely than girls to be diagnosed with autism. But ASDs tend to occur more often than expected among people who have certain other medical conditions, including Fragile X syndrome, tuberous sclerosis, congenital rubella syndrome, and untreated phenylketonuria (PKU). Some harmful drugs taken during pregnancy also have been linked with a higher risk of autism, specifically, the prescription drug thalidomide.
Although most autistic children are diagnosed before the age of three, one of the major challenges in diagnosing and treating autism is the wide variety of symptoms that individuals with autism may demonstrate. No two autistic individuals show the same symptoms to the same degree. However, some of the most common characteristics of autism include:
- Difficulties with social skills that seriously affect the individual’s ability to interact effectively with others
- Serious communication difficulties
- Repeated Behaviors and Routines
The CDC has created a list of possible autism disorder “warning signs” that include:
- Not play "pretend" games (pretend to "feed" a doll)
- Not point at objects to show interest (point at an airplane flying over)
- Not look at objects when another person points at them
- Have trouble relating to others or not have an interest in other people at all
- Avoid eye contact and want to be alone
- Have trouble understanding other people's feelings or talking about their own feelings
- Prefer not to be held or cuddled or might cuddle only when they want to
- Appear to be unaware when other people talk to them but respond to other sounds
- Be very interested in people, but not know how to talk to, play with, or relate to them
- Repeat or echo words or phrases said to them, or repeat words or phrases in place of normal language (echolalia)
- Have trouble expressing their needs using typical words or motions
- Repeat actions over and over again
- Have trouble adapting to changes in routine
- Have unusual reactions to the way things smell, taste, look, feel, or sound
- Lose skills they once had (for instance, stop saying words they were once using)
A Link Between Autism and Vaccines?
The concept of a vaccine-autism link came to the forefront following a publication of a 1998 study by Wakefield and colleagues that linked the Measles, Mumps, Rubella (MMR) to increased prevalence of autism. The authors claimed that the MMR vaccine was linked to the development of autism. However, there are a number of problems with the conclusion reached in this study, which arise primarily as a result of the small sample Wakefield studied (only twelve children). Additionally, a 1999 California report indicated that the number of children with autism increased as a result of the introduction of the MMR vaccine.
More specifically, supporters of the vaccine-autism link blame the thimerosal found in the MMR vaccine for causing autism (as well as other medical problems, including digestive problems and heart problems). A recent study by Drs. Mark and David Grier reported that "U.S. infants are exposed to mercury levels from their childhood-immunization schedule that far exceed the EPA [Environmental Protection Agency] and FDA [Food and Drug Administration]-established maximum permissible levels for the daily oral ingestion of methyl mercury." Could it be that mercury in vaccines is actually causing children to develop autism?
For every study demonstrating a link between the MMR vaccine and autism, there are several others that refute the claim. Many scientists and doctors and found serious flaws with Wakefield’s initial study, citing its small sample size and lack of control group as major problems with accepting its conclusions. Several studies (Dales 2001, Gilberg and Heijbel 1999, Kaye and colleages 2001) – with larger, more reliable sample sizes – have found no correlation between the introduction of the MMR vaccine and the incidences of autism.
The U.S. Centers for Disease Control and Prevention maintain that no proven link exists between the MMR vaccine and the incidence of autism. It still strongly advocates that parents vaccinate their children, stating that although there is no convincing evidence that the MMR vaccine causes autism, the MMR vaccine does prevent a variety of serious diseases that can harm children.
This page has been added by Terra White