Friday, 29 March 2013

Antigen content exposure and autism: no link

I'm hopefully not setting myself up for a fall by discussing the study published by Frank DeStefano and colleagues* (open-access) suggesting no link between the 'too many too soon' argument of vaccination and risk of autism. As probably would be expected with such study results, there has been a flurry of interest on this paper (see here and here for example) and so once again I'm not going to add too much to the details which have already been reported.

The basics:

  • Based on a final comparison of 256 children diagnosed with an autism spectrum disorder (ASD) with an asymptomatic control group of 752 children (all born between 1994 -1999), vaccination histories were examined and exposure to "total antibody-stimulating proteins and polysaccharides from vaccines was determined by summing the antigen content of each vaccine received". 
  • For those like me, who are not too well-versed in the immunological principles of vaccination, the antibody-stimulating proteins and polysaccharides bit basically refers to the constituents of vaccines designed to invoke an immune response and the production of antibodies to recognise and fight the bacteria/virus being vaccinated against. Quite by coincidence, the BBC recently carried an interesting article about new vaccines potentially coming from some analysis on the UK synchrotron, the Diamond Light Source (see here - click on the interactive video) which quite neatly sums up the hows and whys of vaccination. 
  • The study produced odds ratios (ORs) for ASD 'outcomes' during the first 2-years and found no evidence for any increased risk of autism based on antigen exposure. 
  • Bearing in mind quite a few other potentially interfering variables were also collected (maternal exposures, child birth conditions, etc.), the results similarly suggested "no associations when exposures were evaluated as cumulative exposure from birth to 3 months, from birth to 7 months, or from birth to 2 years, or as maximum exposure on a single day during those 3 time period". In short, no statistical association between too many vaccines too soon and autism.

There's little more to say about the findings that hasn't already been said. I've talked before about immunisation uptake in siblings of children with autism (see here) and how the general topic of vaccination has been a real source of discussion/debate/argument in some quarters of the autism landscape; more often than not as a result of the disparity between personal experiences vs. the scientific literature.

Appreciating that quite a few people want to draw a line under the whole vaccination-autism affair in light of this and other data quite explicitly detailing no population-wide link between the two, I'm always open to further scientific inquiry on any aspect of autism. Take for example the work by Harumi Jyonouchi and colleagues on SPAD - specific polysaccharide antibody deficiency - in relation to cases of autism (see here) which may or may not be relevant and which is crying out for further independent replication. Or even the suggestion that post-vaccination paracetamol (acetaminophen) use might be tied into risk of autism as per the paper by Schultz and colleagues** (thanks Jen).

And then there are the various reports on cases being conceded on vaccination and 'autism-like symptoms' developing as per Hannah Polling. Indeed, with the n=1 very firmly in place, I note from the linked Time article "she received an unusually large number of vaccines in 2000 (when thimerosal was still in use). Because of a series of ear infections, Hannah had fallen behind in the vaccine schedule, so in a single day she was given five inoculations covering a total of nine diseases: measles, mumps, rubella, polio, varicella, diphtheria, pertussis, tetanus, and Haemophilus influenzae." According to the DeStefano results, the total antigen load was not an issue? So what might have been the issue/s? Did a mitochondrial problem show some involvement or not? (see the CDC FAQs on this topic).

I'm going to finish this post by highlighting just how important vaccination is (see here, again from the CDC), save any charges of irresponsible blogging being levelled against me. At the same time though, realising that no medicine is infallible and that continued vigilance and monitoring is required as per the article by Roberta Kwok*** and the recent flu vaccination - narcolepsy example.

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* DeStefano F. et al. Increasing Exposure to Antibody-Stimulating Proteins and Polysaccharides in Vaccines Is Not Associated with Risk of Autism. J Pediatrics. March 2013.

** Schultz ST. et al. Acetaminophen (paracetamol) use, measles-mumps-rubella vaccination, and autistic disorder: the results of a parent survey. Autism. 2008; 12: 293-307.

*** Kwok R. Vaccines: The real issues in vaccine safety. Nature. 2011; 473: 436-438.

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ResearchBlogging.org
Frank DeStefano, Cristofer S. Price, & Eric S. Weintraub (2013). Increasing Exposure to Antibody-Stimulating Proteins and Polysaccharides in Vaccines Is Not Associated with Risk of Autism The Journal of Pediatrics

5 comments:

  1. I once read that Hannah Poling had a unique type of mitochondrial disease.Supposedly there are hundreds,if not thousands,of different mutations.I am learning all too well about mitochondrial disease and autism.While cerebral folate deficiency syndrome explains my autism,it does not explain my lack of muscle development,many medical problems,and frequent regressions.If you read the articles by Richard Frye,and others,you know cerebral folate deficiency syndrome is often a secondary condition to mitochondrial disease,or other metabolic disease.I am now on the waiting list to be seen at Arkansas Children's.

    Mitochondrial disease is just one disease that can present as autism,where fever,natural or vaccine induced,can cause regression,and present as autism.Dravet Syndrome is another.

    While you will never rid "correlation equals causation" from the minds of parents,you could help prevent it,by having doctors better educate parents about these diseases,and the potential for regression.As someone who struggled for decades for an adequate diagnosis,or real any medical care,fighting all sorts of undereducated,and ignorant doctors,I know just these parents face from their primary care doctors.I think these diseases are probably seriously underdiagnosed,and not as rare as many doctors think.

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    1. Thanks Roger.

      You raise some important points there about comorbidity and its underdiagnosis.

      I'm very aware of the research fountain that is Richard Frye and colleagues and their focus on some of those comorbidities, which represent some very interesting directions for a much wider research agenda. It's a slow process but there is a realisation emerging that (a) autism is probably more the 'autisms' and (b) a diagnosis of autism is not seemingly protective against other conditions.

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  2. I have my own two cents about vaccinations. I have this ugly birthmark. I have considered getting rid of it for years. It's red land sometimes lumpy. If I were to get it removed I could have a reaction to the anesthesia (topical or not). There could be a gross mistake by the medical professional and have my finger cut off by mistake. My stitches could become infected; perhaps with MRSA. I could die of allergic reaction to the antibiotics.

    All medical interventions have risk. If you don't want to risk the hypothetical chance of autism from vaccines, you are risking the real risk of measles which has been going around the states.

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    1. Thanks for the comment Sarah Jane.

      Risk is an integral part of everyday life and as you suggest, vaccination does prevent diseases and save lives.

      As per the Kwok article, this does not however prohibit research and discussion on the possibility - however small - that side-effects can occur (as with any medicine). The onus is to continually make products safer and safer (as per what might occur from the synchotron work) and, where appropriate, ensure that those who do suffer side-effects are properly taken care of including learning any lessons that need to be learned.

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    2. The million dollar question is what is the hypothetical risk? The con founder here could be mito issues, low glutathione due to illness / oxidative stress, or genetic susceptibility which we don't quite know enough about and cannot adjust in any study yet. If the risk is say 50% of such susceptible kids, then it isn't quite the same risk as getting an infection from the stitches.

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