Study shows lower autism rate in vaccinated kids

3 Dec

A study just released claims that kids who are vaccinated against measles have a much lower autism rate.

The sudy was published in The Pediatric infectious disease journal.

Lack of Association Between Measles-Mumps-Rubella Vaccination and Autism in Children: A Case-Control Study

the team is out of Poland:

Mrozek-Budzyn D, Kietyka A, Majewska R.

From the Department of Epidemiology and Preventive Medicine, Jagiellonian University, Collegium Medicum, Krakow, Poland.

Here is the abstract:

OBJECTIVE:: The first objective of the study was to determine whether there is a relationship between the measles-mumps-rubella (MMR) vaccination and autism in children. The second objective was to examine whether the risk of autism differs between use of MMR and the single measles vaccine. DESIGN:: Case-control study. STUDY POPULATION:: The 96 cases with childhood or atypical autism, aged 2 to 15, were included into the study group. Controls consisted of 192 children individually matched to cases by year of birth, sex, and general practitioners. METHODS:: Data on autism diagnosis and vaccination history were from physicians. Data on the other probable autism risk factors were collected from mothers. Logistic conditional regression was used to assess the risk of autism resulting from vaccination. Assessment was made for children vaccinated (1) Before diagnosis of autism, and (2) Before first symptoms of autism onset. Odds ratios were adjusted to mother’s age, medication during pregnancy, gestation time, perinatal injury and Apgar score. RESULTS:: For children vaccinated before diagnosis, autism risk was lower in children vaccinated with MMR than in the nonvaccinated (OR: 0.17, 95% CI: 0.06-0.52) as well as to vaccinated with single measles vaccine (OR: 0.44, 95% CI: 0.22-0.91). The risk for vaccinated versus nonvaccinated (independent of vaccine type) was 0.28 (95% CI: 0.10-0.76). The risk connected with being vaccinated before onset of first symptoms was significantly lower only for MMR versus single vaccine (OR: 0.47, 95% CI: 0.22-0.99). CONCLUSIONS:: The study provides evidence against the association of autism with either MMR or a single measles vaccine.

If we take these results at face value, the MMR vaccine may prevent autism. Also the single measles vaccine, recommended by Dr. Wakefield, is less “safe” than the MMR.

To be honest, I don’t think these results are consistent with previous, large population studies of MMR and autism. An odds ratio of 0.17 (meaning you are six times more likely to be autistic if you didn’t get the MMR) should have been picked up.

I look forward to reading the full study. Somehow I doubt it will be posted to the Generation Rescue or SafeMinds websites!

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16 Responses to “Study shows lower autism rate in vaccinated kids”

  1. Leila December 3, 2009 at 17:45 #

    The other possibility – families with an older child with autism don’t vaccinate their other offspring for MMR but they may become autistic anyway.

    • Sullivan December 3, 2009 at 17:55 #

      Leila,

      that would also be consistent with the higher risk for single measles vaccine–siblings may be more likely to get the single.

      But, sibs shouldn’t be that large a portion of the sample group.

  2. Leila December 3, 2009 at 19:07 #

    That’s true about the siblings. But in order to understand the phenomenon a little better, we’d have to know more about the groups who don’t vaccinate their children. We know that parents of autistic children who believe in the vaccine causation are amongst them. Who are the others? People with no access to healthcare? Alternative medicine fans?

    • Sullivan December 3, 2009 at 19:38 #

      Keep in mind, there are kids who were not vaccinated at all, and there were kids who got MMR after symptom onset.

      If you look at only the kids who were never vaccinated for Measles–8 children (8%) in the autism group were never vaccinated for MMR. Only 1 in the control group (0.5%). If one were to use those numbers alone, the uncorrected “odds” of autism associated with MMR would be 16:1.

  3. Joseph December 3, 2009 at 21:23 #

    Did they say whether a lot of the non-vaccinated autistic children were younger siblings of other autistic children?

    • Sullivan December 3, 2009 at 21:29 #

      Joseph,

      a quick skim of the paper indicates no. They don’t note if they were younger siblings. They do list a number of risk factors:

      Other potential risk factors of autism (mother’s age, mother’s
      education, gestation time, medication during pregnancy, perinatal
      injury, and Apgar scale score) were examined and those that
      appeared to be associated with autism (P ! 0.2) were carried
      forward into multivariate models. The statistical significance was
      defined as P ! 0.05. Statistical analyses were performed using
      STATA 8.0.

      It would seem odd for them to list those risk factors and ignore family history of autism.

  4. David N. Brown December 3, 2009 at 23:48 #

    I suspect the simplest explanation here is some kind of “diagnosis” bias. In particular, it would not be surprising if quite a few kids with wealthier and otherwise more “respectable” parents are undiagnosed where poorer children with the same symptoms would be diagnosed. A Terry Pratchett joke that may apply: “Rich people aren’t crazy. Crazy with money is eccentric.”
    It would be useful to know how many of the unvaccinated were from the “anti-vax” upper glass vs. simply “non-vaccinating” poor.

  5. passionlessDrone December 4, 2009 at 03:04 #

    Hi David N. Brown –

    Rich people aren’t crazy. Crazy with money is eccentric.

    Hehe.

    To go nearly completely off topic, a few years ago I read “A Short History of Nearly Everything” by Bill Bryson. It was a great read that I would recommend to anyone. Anyways, your quote reminded me of it, because, it turns out, a lot of the groundwork for things like geology, palentology, and other sciences were done by people who happened to be born rich and just a bit ‘eccentric’, who took a liking to a particular field and had the time and resources to poke around a lot. You might consider checking it out.

    – pD

  6. Emily December 4, 2009 at 04:43 #

    pD–it was just about the only way to spend the time necessary to make those discoveries. Thank goodness for those rich, eccentric, perseverative people. Another one I just read and enjoyed about a handful of that lot is *The Age of Wonder* (Richard Holmes). Those people sure did have a lot of time on their hands, and we all benefit.

    On the paper…did it list any inclusion or exclusion criteria, e.g., “family history of autism”? I’m just thinking that it would be rather odd and obviously potentially confounding to include siblings with and without autism.

  7. tigtog December 4, 2009 at 09:35 #

    I suspect the simplest explanation here is some kind of “diagnosis” bias. In particular, it would not be surprising if quite a few kids with wealthier and otherwise more “respectable” parents are undiagnosed where poorer children with the same symptoms would be diagnosed.

    I think you’ve got the bias the wrong way about there. Wealthier families are more likely to gain access to a full assessment of their child acting “odd”, and will seek it because in many districts a formal diagnosis opens up supported special education opportunities and extra considerations for formal examinations that make it more likely their child will eventually end up in a good college/university. Poorer children are likely to be all chucked into the ADHD blanket diagnosis and just dosed on Ritalin, which although it’s highly effective for a minority is unlikely to be the best medication for most of them, and is certainly not likely to be as effective as a proper special education program with a teacher trained in how to interact with not-neurotypical kids.

    • Sullivan December 4, 2009 at 17:21 #

      What I find interesting here is the fact that this group will take a critical look at a paper which supports their stance. I really don’t see that happening in the so called “vaccine safety” groups.

  8. Prometheus December 4, 2009 at 17:41 #

    Well, it looks like somebody did the study that the “Green Our Vaccines” and “Too many, too soon” groups have been asking for. And – surprise! – they did it the way I suggested (i.e. comparing autistic children with age- and sex-matched “typical” controls).

    However, there has to be a variable they missed, because a 6:1 relative risk would be painfully easy to pick up in the population – and we’re just not seeing that. On the other hand, the upper edge of the confidence interval is 0.52 (about 2:1), and that might be approaching the realm of possible.

    My guess – and I said this when I made my “modest proposal” to study the vaccine-autism “connection” – is that the people who don’t vaccinate their kids may be those with autism in the family tree who have been made fearful of vaccines by the Ignorati. Thus, the “GOV” and “TM,TS” groups may have “poisoned the well” against their own hypothesis.

    I’d love to know how much traction the “vaccines-cause-autism” (and especially the “MMR-causes-autism”) hypothesis has in Poland – I have no idea.

    Prometheus

  9. Laurentius Rex December 5, 2009 at 15:30 #

    I think tig tog is right there.

    It always amazes me though that the same people will take on opposing arguments eg. only rich kids are diagnosed, only poor kids are diagnosed, according to the point they want to prove.

    Given two potentially equally valid positions the only equivocator in the case of judgement on a particular hypothesis is the bias or hunch of the judge, so as in everything it comes down to opinion rather than evidence.

  10. David N. Brown December 6, 2009 at 01:12 #

    tigtog,
    It’s pretty undisputed that, historically, there was “overreporting” of autism in upper vs. lower class families. Now, I suspect bias works in both directions. Where I would expect to see social bias most is in the upper and lower ranges of the spectrum: For example, reporting the son of a rich family as “autistic” would be more expedient than reporting him as “retarded”.

    pD- I read a lot about the history of scientist, and there is plenty of indicators of autism-like tendencies in major historical personalities. What I consider more significant is how contemporary society reacted to mental differences. I find this line about an early American paleontologist especially interesting: “The Indians considered him crazy, and therefore holy.”

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