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Childhood Vaccinations and ASD: No Relationship Between Number or Schedule of Vaccinations and Diagnostic Outcome or Severity

Posted May 12 2011 11:00pm

The International Meeting For Autism Research will be held in May. Abstracts for the conference are public now. One search that will be common amongst the online parent community is to see what research has been done on the question of vaccine causation.

Here is an abstract looking directly at the question. They compared siblings of autistics, children at risk for developmental delays and children expected to develop typically. They found—no evidence of increased risk from vaccination:

A. Margolis1, J. D. Jones2, A. Trubanova2, W. Jones2, K. Chawarska3 and A. Klin2, (1)Yale Child Study Center, Yale University School of Medicine, New Haven, CT, (2)Marcus Autism Center, Children’s Healthcare of Atlanta & Emory School of Medicine, Atlanta, GA, (3)Child Study Center, Yale University School of Medicine, New Haven, CT
Background: Recent increases in the number of recommended childhood vaccines have raised public concerns about the potential side effects of immunizations on children’s health. Because of the increasing prevalence of autism diagnoses over the last 15 years, this disorder, in particular, has become the focus of much of the attention and concern surrounding childhood vaccines. As a consequence of this debate, the use of childhood vaccines, especially the measles-mumps-rubella vaccine (MMR), has decreased significantly, and this decrease has led to numerous outbreaks in diseases previously prevented by vaccines. Furthermore, research addressing the relationship between vaccines and autism has relied primarily on retrospective population studies, with little power to determine the role of immunizations in individual outcomes.

Objectives: The primary goal of this study is to examine the relationship between the frequency and number of childhood immunizations and the subsequent likelihood of developing autism. In addition, this study aims to investigate the relationship between childhood vaccines and disorder severity in children who do go on to develop autism.

Methods: Immunization data were collected for 91 children divided among the following three groups: (1) siblings of children with an autism spectrum disorder diagnosis, (N =48; gender = 37M); (2) children at risk for developmental delays (N = 7; gender = 5M); and (3) children expected to develop typically (N = 36; gender = 19M). All children were at least 2 years of age when their immunization records were collected. Individual immunization data were recorded and then compared with diagnostic outcome and behavioral data.

Results: Tests of association and linear multiple regressions revealed that neither a greater number of childhood vaccines nor a higher rate of vaccination had a positive relationship with subsequent autism spectrum diagnosis (N=8; gender=7M) or disorder severity, which was assessed in all participants. In addition, comparison of immunization data to behavioral indicators at 2 years of age did not reveal any relationship between either higher frequency or greater number of childhood vaccines and subsequent negative behavioral outcomes. Likewise, neither vaccination with MMR nor the age of MMR vaccination was significantly related to outcome. Instead, because siblings of children with autism were less likely to be vaccinated according to the recommended schedule, both correlations and multiple regressions revealed a significant relationship between higher rates of vaccination and non-ASD behavioral outcomes.

Conclusions: These results suggest that childhood vaccines do not increase children’s risk of developing autism and do not exacerbate the disorder severity in children who are later diagnosed with autism. Children who receive a greater number of vaccines overall, who receive the MMR vaccine, or who receive immunizations at a higher rate, do not differ significantly on subsequent behavioral measures from children who receive vaccines on an alternative schedule or children who do not receive vaccines. Instead, the results of this study emphasize heritability in risk for autism, and also indicate that siblings of children with an autism diagnosis are less likely to be vaccinated, which actually increases their risk for contracting other illnesses.

Here’s an observation that has often been predicted: ” Instead, because siblings of children with autism were less likely to be vaccinated according to the recommended schedule, both correlations and multiple regressions revealed a significant relationship between higher rates of vaccination and non-ASD behavioral outcomes.” I believe this very point has been predicted by blogger Prometheus a number of times.

The study is relatively small in my opinion. With 91 participants, the number of autistics is likely small. Also, this will focus on familial autism. There may very well be a difference between the types of autism which run in families and that which is more sporadic.

Note—I originally posted this in April when the abstracts were first put online. They were online in error, as there was an embargo in place. The post was taken down at that time and I’ve now made it live again since the embargo is lifted.

  1. passionlessDrone:
    Hello friends -Instead, because siblings of children with autism were less likely to be vaccinated according to the recommended schedule, both correlations and multiple regressions revealed a significant relationship between higher rates of vaccination and non-ASD behavioral outcomes.I've read that a few times. Does this mean that they 'found' that higher rates of vaccination was associated with behavioral outcomes other than ASD? I guess trying to glean to much from an abstract is problematic. Can someone re-word it for me into dumbspeak if I'm missing it?The study is relatively small in my opinion. With 91 participants, the number of autistics is likely small.They still found tons of autism; 8 kids or almost 9%. You'd expect that if you had 91 siblings and a 10% non twin sibling rate, but they only had 48 siblings of children with autism.It really seems curious that they'd find any autism in their group of 36 of 'normal' infants, though why, why, why did they decide to go with a ~ 50% male/female ratio in that population only? Ack.The IMFAR program does have lots of neat stuff.Thanks for posting this. - pD
  2. Orange Lantern:
    My interpretation of that sentence is that more vaccines was associated with less autism (more non-ASD outcomes). The siblings of autistic children were less vaccinated, but at increased risk of developing autism because of their genes.
  3. Prometheus:
    Pretty much what I've predicted - the genetic nature of autism coupled with the reluctance of parents of an autistic child to vaccinate subsequent children (thank you Wakefield, et al!) has led to a (false) association between not vaccinating and autism.Now, will AoA and the rest be issuing a statement about how vaccines don't cause autism, based on the results of this study? I doubt it.Let me anticipate their response to this study:
    "Flawed! Corrupt! Conflict of interest! Big Pharma! Vaccine manufacturers paid for these results! We need another study - one that's done by our scientists (and arrives at the 'correct' results)!"
    Prometheus
  4. sharon:
    THanks for your question pD, I too was struggling to interpret that statement. Prometheus can you expand on what you mean by the false association between not vaccinating and Autism?
  5. Sullivan:
    Sharon,if you take the population of kids who are unvaccinated, it is very likely that they have a large fraction of siblings of autistic kids. Older kid gets diagnosed, parents decide not to vaccinate the younger kids.Siblings of autistic kids are more likely to be autistic.Add the two together and you get a group of unvaccinated kids who have a higher autism prevalence. It isn't that being unvaccinated causes autism, it's because so many of the unvaccinated are younger siblings of autistic kids.

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