No Evidence for A New Variant of Measles-Mumps-Rubella–Induced Autism

Abstract

ABSTRACT. Objective. A link has been postulated between measles-mumps-rubella (MMR) vaccine and a form of autism that is a combination of developmental regression and gastrointestinal symptoms that occur shortly after immunization. This hypothesis has involved 3 separate claims: 1) that there is new phenotype of autism involving regression and gastrointestinal symptoms, 2) that this new variant is responsible for the alleged rise of autism rates, and 3) that this phenotype is associated with biological findings suggestive of the persistence of measles infection. We tested the first of these claims. If this new "autistic enterocolitis" syndrome had some validity, then 1 or several of the following 6 predictions should be supported by empirical data: 1) childhood disintegrative disorder has become more frequent, 2) the mean age of first parental concern for autistic children who are exposed to MMR is closer to the mean immunization age than in children who are not exposed to MMR, 3) regression in the development of children with autism has become more common in MMR-vaccinated children, 4) the age of onset for autistic children with regression clusters around the MMR immunization date and is different from that of autistic children without regression, 5) children with regressive autism have distinct symptom and severity profiles, and 6) regressive autism is associated with gastrointestinal symptoms and/or inflammatory bowel disorder.Methods. Three samples were used. Epidemiologic data on 96 children (95 immunized with MMR at a median age of 13.5 months) who were born between 1992 and 1995 and had a pervasive developmental disorder diagnosis as reported in a recent UK survey (post-MMR sample) were compared with data from 2 previous clinical samples (1 pre-MMR [n ‫؍‬ 98] and 1 post-MMR [n ‫؍‬ 68]) of autistic patients. All patients were assessed with the standardized Autism Diagnostic Interview (ADI), allowing rigorous comparison of age at first parental concerns and rates of regression across samples. Reliability was excellent on ADI scores, age of parental concern, and developmental regression. Furthermore, data on bowel symptoms and disorders were available in the epidemiologic survey from both pediatric and parental sources, and immunization dates were obtained from computerized records.Results. The prevalence of childhood disintegrative disorder was 0.6/10 000 (95% confidence interval: 0.02-3.6/10 000); this very low rate is consistent with previous estimates and is not suggestive of an increased frequency of this form of pervasive developmental disorder in samples of children who are immunized with MMR. There was no difference in the mean age at first parental concern between the 2 samples exposed to MMR (19.3 and 19.2 months) and the pre-MMR sample (19.5 months). Thus, MMR immunization was not associated with a shift toward an earlier age for first parental concerns. Similarly, the rate of developmental regression reported in the post-MMR sample (15.6%) was not different from that in the pre-MMR sample (18.4%)...

Familial Autoimmune Thyroid Disease as a Risk Factor for Regression in Children with Autism Spectrum Disorder: A CPEA Study

“…In their report citing no evidence for a new variant of MMR-induced autism, Fombonne and Chakrabarti found no differences between regression and nonregression groups on symptom severity as measured by ADI scores, but they did report a difference in cognitive functioning that approached significance, with 46.1% of children in the regression group having an IQ<70 compared to 21.5% of the nonregression group (p=0.08, Fisher's exact test) (Fombonne & Chakrabarti, 2001). Brown and Prelock (1995) also reported that individuals with autism and regression had poorer social skills later in life compared to those with autism and no regression.…”

MMR and autistic enterocolitis: consistent epidemiological failure to find an association

“…In this large (n ¼ 473) sample, 17% of children were reported to have suffered from gastrointestinal symptoms lasting 3 months or more, and 25% were reported to have lost skills or regressed in their development, findings that are consistent with other epidemiological surveys. 11 No change over time was reported for both regression and occurrence of gastrointestinal symptoms, and results were similar for both typical and atypical forms of autism. Furthermore, the rates of both problems did not differ in children for whom parents first became concerned before the MMR immunization, as compared to those for whom parents became concerned after the MMR immunization.…”

“…6 Several epidemiological investigations have tested the association between trends in rates of autism and either the introduction of measles-mumps-rubella (MMR) vaccine 7 or variations in MMR uptake, 8,9 and they all failed to demonstrate an association. Further analyses have examined whether or not regression in the course of autism 10,11 or health-seeking behavior by parents 12 clustered after MMR vaccination, and no evidence of time clustering was found. More recently, a large population-based cohort study of over 500,000 Danish children has shown no increase in the incidence of autism in children exposed to MMR compared to unexposed children.…”

“…Although the clinical phenotype in question varied from account to account, Wakefield et al 3 had argued once that the most distinctive features of their new autism variant consisted of regression in the developmental course associated with gastrointestinal symptoms, although precise delineation of this 'autistic enterocolitis' has been largely missing. 5,11 In this context, the recent publication by Taylor et al 14 adds new empirical evidence in the debate. Taking Wakefield's hypotheses strictly, they investigated in a long time series of autism cases whether or not the regressive form of autism and the incidence of gastrointestinal symptoms had increased over time, looking particularly at a step-up in rates of these specific syndromes after the 1988 mass introduction of MMR in the UK.…”

A Review on the Cognitive Neuroscience of Autism

“…Additional evidence includes primarily anecdotal reports, from parents noticing the onset of autism closely following immunization. Epidemiological evidence consistently does not support any correlation between the administration of the MMR vaccine and the incidence of autism (Chen, Landau, Sham, & Fombonne, 2004;Fombonne & Chakrabarti, 2001;Kaye, del Mar Melero-Montes, & Jick, 2001;Taylor et al, 1999), suggesting that anecdotal evidence may often be due to the concordance in the age of MMR vaccination and onset of autistic symptomatology. Another related theory is autism induced by neurotoxic levels of mercury, or from the presence of ethylmercury in the vaccine preservative thimerosal.…”