Do Immunizations Cause Autism

By Ivy Fisher, M.D.

Autism Spectrum Disorders (ASD) is a collection of chronic neuro-developmental disorders that

share in the hallmark features of impaired social interaction, communication, and restrictive and repetitive interests and activities. It is four times more common in males and the incidence has risen 284 percent over the past 18 years. The causes of autism remain mysterious, though it is known to be genetically based affecting five or more genes during the first month of pregnancy.

There are a myriad number of theories on its etiology, including infectious (viral, bacterial, fungal), metabolic, immune (enzymatic, hormonal), toxic (thimerosal, mercury, heavy metals, contaminated water), secretin, serotonin, and others.

The more controversial issue is whether there is an associative link between ASD and the MMR vaccine. This was based on English researcher Dr. Andrew J. Wakefield’s work published in The Lancet (1998: 351: p. 637-640 and 1999: 353: p. 1987-88). He studied 12 children, who after receiving the MMR vaccine, developed irritable bowel syndrome (IBD), leading to a regressive developmental disorder. The monovalent vaccine or natural infection didn’t have this altered immune response to antigens or persistent infection. No scientific analyses substantiated this claim, nor was referral bias and small sample size considered. Four of the 12 children had behavioral problems before getting IBD, and the measles virus wasn’t demonstrated to be present on culture and, therefore, not directly responsible for the IBD. The features of ASD often present during the time period of giving the MMR vaccine at 15 months, so it is evidently parallel timing, not causative.

However, more recent double-blinded scientific studies refute this associative cause. In the United Kingdom, Brent Taylor in The Lancet (1998 vol 2: 423-424 and June 12, 1999, vol 353: p. 2026-2029) did not find MMR vaccine the cause of increased cases of ASD in London. The study followed 498 children after the MMR vaccine; there was no increased expression of ASD symptoms in the children. When the MMR vaccine was removed, there was still an increasing incidence of ASD. In the United States, the National Alliance for Autism Research (NAAR) and eight Genetic Exchange Research Centers have run a multitude of studies supporting the lack of scientific evidence that MMR vaccine or thimerosal causes autism. The media has reported this link on TV news and the Internet, making it an even more hard sell for pediatricians to vaccinate children. A recent example is from Slate magazine, where Bobby Kennedy Jr., a lawyer and activist against mercury in coal-burning power plants, now has become outspoken about the use of thimerosal in vaccines causing the ASD increase. Now, an AAP panel has reviewed thoroughly with world-renown specialists significant data that educate and support the use of MMR and other vaccines as safe. In Pediatrics (2001; 107:e84), the evidence did not show this link. In the March 7 issue of JAMA (JAMA 2001; 285:1183-1185), the California data on MMR vaccine given from 1980 to 1994 did not demonstrate a corresponding increase in ASD cases. The British Medical Journal (2001; 322: 460-463) found the same conclusion. Other studies have included Gillberg & Heijbel (1998) who found no association between 1975 to 1984 in Sweden and Madsen et al (2002) in Denmark, who studied 537,303 children from January 1991 to December 1998 and found no link. Also, there was no increase in ASD with either monovalent measles or combined MMR.

The AMA, AAP, and the federal government studies spearheaded by CADDRE (Center for Autism and Developmental Disabilities for Research and Epidemiology) have all concluded that there is an absence of evidence-based association that MMR vaccine causes autism. Figures of ASD increase were based on numbers, not rates, and don’t account for the population growth and changes in the composition of the population. Also, changes in the diagnostic definitions of ASD are not controlled in Wakefield’s study, nor is the fact that earlier diagnosis of ASD is being made now, which would naturally raise the number of reported cases. In 2004 Wakefield and 10 of the 13 authors of his study retracted their findings due to insufficient data, and it couldn’t be reproduced by Afzal ’98 and Iizuka ’00. Pediatricians should now feel comfortable using MMR vaccine and recommending it for their patients. 

 Dr. Fisher is a pediatrician in Daly City.