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The MMR (measles/mumps/rubella) vaccine and autism - is there a link?
Recently, TV shows, including 60 Minutes (11/12/2000), have been discussing this issue. The Center for Disease Control (CDC), the American Academy of Pediatrics (AAP), the American Medical Association (AMA), and the Institute of Medicine believe there is NO current scientific evidence to support a link between the MMR vaccine and autism. On this page we will discuss the issues and recommend links to other informative web sites.

What are measles, mumps, and rubella?

All three of these diseases are caused by viruses.

The measles virus causes 3-4 days of red eyes, cough, runny nose, and fever, which is followed by a red blotchy rash beginning on the face and spreading over the entire body. Children with measles tend to feel miserable. The rash usually lasts about 7 days. Children usually begin to feel better by the 4th day of the rash (7th day of the illness).

Measles can be a dangerous illness causing the following complications:

  • Death (2-3 out of every 1000 cases - though in children under 5 years of age the death rate is higher)
  • Encephalitis - a serious brain infection that frequently results in permanent damage (1 out of every 1000 cases)
  • Ear infections
  • Pneumonia
  • Diarrhea
  • Croup
  • Dehydration
  • Hospitalization (1-2 out of every 100 cases)
  • Subacute sclerosing panencephalitis - a degenerative brain disease occurring many years after measles infection that results in seizures and intellectual deterioration

The mumps virus causes fever and swelling of the salivary glands (especially the parotid glands located on our cheeks just in front of our ears). Complications of mumps infection include:

  • Meningitis (5 out of every 100 cases)
  • Orchitis (swelling of the male testicles which may lead to sterility) - occurs in 4 out of every 10 post-pubertal male
  • Arthritis
  • Thyroiditis (infection of the thyroid gland)
  • Infections of the heart and kidney
  • Low platelet count resulting in bleeding problems
  • Hearing loss (permanent)
  • Other neurologic complications

The rubella virus (German measles or 3 day measles) causes fever, swollen lymph nodes in the back of the neck, and a red rash that begins on the face and rapidly spreads over the body. The disease lasts about 3-4 days and is usually mild. However, if a pregnant woman is exposed to rubella, the complications to her fetus may be very severe. There is at least an 80% chance of affecting the fetus if a pregnant woman is infected early in pregnancy. The complications include:

  • Deafness
  • Cataracts
  • Heart defects
  • Growth retardation
  • Encephalitis - a severe brain infection
  • Mental retardation

What is autism?

Autism is a developmental disorder that is often first identified in children between the ages of 18 and 30 months. It consists of a combination of abnormal social interactions, language/speech delay with communication difficulty, and restricted and repetitive behaviors.

Is there a link between the MMR vaccine and autism?

There is NO scientific evidence for such a link. Many organizations including the Center for Disease Control (CDC), the American Academy of Pediatrics (AAP), the American Medical Association (AMA), the Institute of Medicine, the National Alliance for Autism Research, the British Medical Research Committee, and the British Committee on Safety of Medicines, believe that there is no scientifically proven link between autism and the MMR vaccine.

A recent study in the journal Lancet has shown that there is no assocaition between autism and the MMR vaccine ("No Evidence for Measles, Mumps, and Rubella Vaccine-Associated Inflammatory Bowel Disease or Autism in a 14-Year Prospective Study" (The Lancet, vol. 351: May 2, 1998). Visit: www.vaccinesafety.edu/mmrandibd.htm.

Increasing evidence supports the belief that autism is determined early in pregnancy (likely the first trimester).

What about the one study by Dr. Andrew Wakefield of the Royal Free Hospital in the United Kingdom that brought the media to question if there was a link?

Dr. Wakefield’s study has numerous limitations. This study looked at only 12 children who had both autism and bowel disease. Without using scientific analyses, the authors theorized that the MMR vaccine causes autism based on anecdotal evidence. They proposed that the MMR vaccine allows the measles virus to infect the bowel and reduce the absorption of nutrients, which possibly could lead to developmental disorders such as autism. Dr. Wakefield claimed that he evaluated biopsy specimens from the bowels of these patients and found measles virus. These same specimens were further evaluated by experts (including Dr. Wakefield) who found NO evidence of the measles virus. They did find normal intestine proteins that they believe Dr. Wakefield misidentified. (click here to see references of these two papers). Therefore, Dr. Wakefield’s original article does NOT support a link between autism and the MMR vaccine.

Is there evidence that the rise in autism is NOT related to the MMR vaccine?

Yes!

Population based studies in England have shown the following:

  • The number of autism cases have been increasing since 1979. However, in England, after the MMR vaccine was introduced in 1988 the rate of increase has NOT changed.
  • The timing of the vaccination does not change the average age of autism onset. In other words, if the vaccine caused autism, one should expect to see a later onset of autism if the vaccine was given after 18 months of age as compared to an earlier onset of autism if the vaccine was given prior to 18 months of age. However, this was NOT seen, thus showing that a causal link between the two is unlikely.
  • At age 2 years, the rate of autism in children who had received and had not received the was identical. Therefore, receiving the vaccine did not increase the risk to develop autism.

Many studies around the world are currently being conducted to help determine the causes for autism. Currently there is NO scientifically proven evidence that the MMR vaccine causes autism.

Where can I find more info?

Autism and Vaccine Research (National Institute of Child Health and Human Development). Visit: www.nichd.nih.gov/publications/pubs/autism2.htm

Vaccines Do Not Cause Autism" (American Medical Association). Visit: www.ama-assn.org/med-sci/immunize/vacautism.htm

"No Evidence for Measles, Mumps, and Rubella Vaccine-Associated Inflammatory Bowel Disease or Autism in a 14-Year Prospective Study" (The Lancet, vol. 351: May 2, 1998). Visit: www.vaccinesafety.edu/mmrandibd.htm

"No New Evidence of a Link Between MMR And Autism" (Medical Research Council, United Kingdom). Visit: www.mrc.ac.uk/whats_new/press_release/PR_2000/mrc_18_00.html

If you have additional questions, please discuss them with your child's nurse or practitioner.

NEW UPDATE SECTION - below includes recent updated material concerning this issue.

New update (1/21/01): 2 recent studies (part of the Collaborative Program of Excellence in Autism) give more evidence that there is a GENETIC basis for autism. These studies have been reported in (Teratology 62(6):393-405, 2000) and (Am. J. Med. Genet. 96(6):765-770, 2000).

New update (4/23/01): The Institute of Medicine released its first report on April 23, 2001. The reports states that there is no relationship between the MMR vaccine and autism. For more information visit the IOM's website at www.iom.edu/imsafety.

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