Vaccines and autism: a thoughtful debate 1

I have just started watching the video of the debate between David Kirby and Arthur Allen on the subject of autism and vaccines. Kirby wrote a book, Evidence of Harm: Mercury in Vaccines and the Autism Epidemic: A Medical Controversy which starts from the premise that the rapid growth in recorded cases of autism in the USA that began in the early 1990s represented a real growth in numbers and could not be explaind by increased awareness, better diagnostic procedures or a change in the criteria. There had to be an environmental trigger. At the same time changes in the mandatory vaccination programme for children in the USA  increased exposure to thimerosal, a preservative that contains ethyl mercury.  

Did the thimerosal cause an autism epidemic? Kirby believes it did. Allen once thought it was a credible hypothesis. But in the course of researching his book, Vaccine, the Controversial Story of Medicine’s Greatest Lifesaver, Allen changed his mind.  Allen has also begun to question whether there has been an epidemic or not. See his review of Roy Grinker’s book, Unstrange Minds, Remapping the World of Autism. 

I was looking forward to the debate. But within minutes I was hitting the pause button and diving into my archive of autism related papers. Kirby began, quite rightly, with a discussion of epidemiology. But his version seemed at odds with what I thought I knew. Still, this was an important debate. Kirby must have checked his facts beforehand. So I went to check mine.

Kirby’s Fact 1.

In the 1980s autism prevalence in the USA was between 1 and 2 in 10,000

If anyone has a reference to an epidemiological study for this extremely low figure I would love to have it.  When Lorna Wing surveyed the major epidemiological studies carried out between 1966 and 1992 she referred to two studies in Utah (Ritvo et al 1989) and North Dakota (Burd et al 1987) that found rates of 4 and 3.3 in 10,000 respectively for DSM III autism which use very similar criteria to Kanner’s criteria. She also mentioned a study by Treffert which found a prevalence of 3 in 10,000 in 1970 in Wisconsin. When I considered Wing’s survey in an earlier post  I remarked upon the robust nature of the figures. Researchers who combined consistent epidemiological methods with Kanner’s diagnostic criteria found rates of between 4 and 5 in 10,000.

Kirby’s Fact 2.

In the late 1990s autism prevalence in the USA was 20 in 10,000

Kirby offers no citations for this figure. Probably the most well founded study in the USA in the 1990s was by Yeargin-Allsopp et al in Atlanta in 1996 which found a rate of 34 in 10,000 in 3-10 year olds. It was reprinted in JAMA in 2003. In the same edition Fombonne considers this an underestimate and thinks the 5 to 8 year olds in the study provide a more reliable estimate of 41 – 45 in 10,000. (JAMA 2003 Volume 289 Issue 1.)For comparison Wing and Gould found a rate of 20 in 10,000 in the Camberwell study in 1979. This study confined itself to children with learning dificulties in special schools and never looked at children in mainstream classes where most autistic children are found today.

Kirby’s Fact 3.

By 2000 autism prevalence in the USA was 40 in 10,000

Again there is no citation. And autism prevalence in whom? What is the age cohort?

Kirby’s Fact 4.

By 2004 autism prevalence in the USA was 60 in 10,000

We do have a lot of epidemiology for this figure.It is supported by the Medical Research Council in the UK and the Centers for Disease Control in the USA. But it is usually taken to mean that we have now reached a reasonably accurate estimate of prevalence figures for the entire autistic spectrum across the entire population. Kirby sems to be using these figures to suggest a year on year increase in incidence which is not the same as prevalence. Generation Rescue made a similar mistake last year which I commented on.

When you are dealing with statistics it is important not to get incidence and prevalence muddled up. Incidence refers to the number of new cases in a population over a period of time. Prevalence refers to the total number of cases in a given population at a specific time.

Kirby’s Fact 5.

By 2004 th USA figure of 60 in 10,000 was the same as in the UK. But the USA had 40 in 10,000 with autstic disorder and only 20 in 10,000 with other ASDs. In Britain the figures are reversed: 20 in 10,000 with Autistic disorder and 40 in 10,000 with other ASDs.

Kirby’s explanation is simple. Here in the UK we only ever had half the thimerosal in our vaccines compared to our American cousins. So we only got half the autistic disorder. OK. Thimerosal causes autistic disorder. There is a linear relationship. Double the thimerosal and you double the autistic disorder. So what causes PDD-NOS and Asperger Syndrome? Why should they be twice as prevalent in the UK as in the USA? Is that environmental or genetic? Perhaps we Brits are naturally more high functioning than the Yanks 🙂

By this time I was beginning to get a little bit sceptical about Kirby’s figures. He actually did mention a source for his 40 in 10,000 with autistic disorder, Brick Township. I remember that one; 40 in 10,000 for autistic disorder is correct. But the figure in Brick Township for other ASDs was not 20 in 10,000. it was 27 in 10,000. 67 in 10,000! That is a lot of autism, except for one fact. It was a very small sample; 60 children aged 3 to 10. The authors acknowledge the problems in generalizing from their data.

As mentioned earlier, the major limitation of this study was an inability to ascertain higher functioning individuals who were not in any special education class in public schools or had not been seen by participating clinicians. Consequently, because of these case-finding limitations, the results from Brick Township must be considered a minimal prevalence for autism. Categorical distinctions between autistic disorder and the other ASD were probably limited because the ADOS-G has been found to over estimate autistic disorder relative to PDD-NOS. Also, because clinical assessments could not be conducted for 17 children and the diagnosis had to be based on records alone, the reliability and validity of the diagnosis for those children is limited. Discrimination between PDD-NOS and autistic disorder also may have been influenced for these cases given that over 56% of the children who participated in the clinical assessment were determined to have autistic disorder in comparison to only 27% of the children assessed by record review only. Finally, the prevalence rates for autism obtained in this study must be generalized with caution since the community was selected for study because of a suspicion of increased numbers of children with the disorder. Studies of larger populations, such as one that included surrounding communities, may yield different findings.

They may indeed.

Kirby’s Fact 6

Denmark removed all its thimerosal way back in 1992 and it has a rate of only 8 in 10,000.

Yes, except that according to this study autism rates went up in Denmark after they removed the thimerosal. Actually the base rates for autism in this study were so low it is ridiculous, less than 1 in a 1000 throughout the seventies and eighties. That is less than Brask found in 1972 in Denmark for Kanner’s autism. (4.3 in 10,000) A more recent study suggests the real rate for ASDs in Denmark is closer to the 34 in 10, 000 that Yeargin-Allsopp found in Atlanta in 1996. the authors conclude:

We found that the estimated prevalences of the PDDs studied were probably underestimated. Furthermore, the increasing prevalence and incidence rates during the 1990s may well be explained by changes in the registration procedures and more awareness of the disorders, although a true increase in the incidence cannot be ruled out.

So much for Denmark then. I cannot say that  I am looking forward to the rest of this debate if this is the standard of evidence employed by Kirby. But I will resist the temptation to fast forward to Arthur Allen. I will do my blogging duty. Speaking of Arthur Allen, he has written about the debate on his blog and is open to comments. Kirby, despite boasting that whenever he writes on the Huffington Post he goes straight to number one, has yet to share his thoughts on the debate with a wider audience.

 STOP PRESS Kirby has made the slides  from his presentation available on his website. I wont be downloading them just yet. I don’t want to spoil the ending.

to be continued …

EDIT

… or not. Kev has blogged the debate here and here. So has Joseph, BC and D0’C. And Diva has set it to music.

David Kirby is out to hunch

David Kirby, author of “Evidence of Harm, Mercury in Vaccines and the Autism Epidemic” has finally agreed that there is no autism epidemic.

“My hunch (and yes, that is all it is) is that most of these kids do not have “autism” at all, and it’s probably time we started calling it something else.”

He calls this “something else” Environmentally-acquired Neuroimmune Disorder. And he no longer thinks that it had to be caused by mercury in vaccines. Now the mercury is gone it is being caused by

 “radical changes in our environment over the last 10-20 years. There is something, or more likely some things in our modern air, water, food and drugs that are making genetically susceptible children sick, and we need to find out what they are.”

So all the award winning journalism that went into the book, all the scientific research he quotes to support the idea of an autism epidemic caused by mercury in vaccines, all this is dismissed on the basis of a hunch. Oh, and there is the small fact that, contrary to Kirby’s prediction, autism is not going into decline now that all mandatory vaccines for children in the US are mercury free.

My hunch is different to Kirby’s. My hunch is that the people he listened to were wrong. The science he quoted was wrong. The book he wrote was wrong. And his latest response shows that he is still wrong.

He begins with an appeal for sympathy.

“I continue to be vilified by critics who insist that mercury does not cause autism, that autism is a stable genetic condition, and that it cannot be an “epidemic.””

Vilified? His ideas have been criticized. He has been presented with counter arguments. But personal vilification? I suggest he visits the Hating Autism blog to read some really vile things written by one of his supporters about autistic adults who disagree with him.

He goes on to propose a truce with the “neurodiversity” community. His quote marks suggest he does not fully accept the validity of the concept of neurodiversity. He certainly does not understand it. For he goes on to refer to the “neurodiverse” as synonymous with Asperger Syndrome. I suggest he reads my article on Neurodiversity and Kev’s excellent blog from yesterday.

The nature of the truce is this. He supports the rights of the “neurodiverse” to be respected and accepted. But he wants them to accept that they have nothing in common with the really severe autistic children he has met. 

  1. I am talking about kids who begin talking and then, suddenly, never say another word.
  2. I’m talking about kids who may never learn to read, write, tie their shoes or fall in love.
  3. I’m talking about kids who sometimes wail in torture at three in the morning because something inside them hurts like a burning coal, but they can’t say what or where it is.
  4. I’m talking about kids who can barely keep food in their inflamed, distressed guts, and when they do, it winds up in rivers of diarrhea or swirls of feces spread on a favorite carpet or pet (no one said this kind of “autism” was pretty).
  5. I’m talking about kids who escape from their home in a blaze of alarms, only to be found hours later, freezing, alone and wandering the Interstate.
  6. I’m talking about kids who have bitten their mother so hard and so often, they are on a first name basis at the emergency room.
  7. I’m talking about kids who spin like fireworks until they fall and crack their heads, kids who will play with a pencil but not with their sister, kids who stare at nothing and scream at everything and don’t even realize it when their dad comes home from work.

These are the kids I want to see cured. And I don’t believe they have “autism.”

Let us go through that list.

  1. This looks like regressive autism. It accounts for a minority of autistic cases but figures are hard to come by as it is not always certain whether studies are measuring it against DSM-IV autism,  or with the whole autistic spectrum.  There is a further confound because, as I argued in a much earlier blog, much of the evidence for regression comes from parental reports. And it is not always clear whether they are reporting regression or failure to meet expected milestones. It is also necessary to exercise caution when dealing with parental evidence. […]“ A review of each record showed that in 13 children the history given by the parents had changed after the extensive publicity about MMR vaccine and autism. Before the publicity the parents often reported concerns early in their child’s life, usually before their first birthday; the current history for the same children recorded symptoms as developing only after MMR vaccination, in some cases shortly after.”
    (Taylor, Miller, Lingam, Andrews, Simmons & Stowe (2002) Measles, mumps, and rubella vaccination and bowel problems or developmental regression in children with autism: population study British Medical Journal, 2002, Vol. 324, pp. 393-396)
  2. This describes a lot of the children I teach. Some are autistic. Some are not. And note Kirby’s use of “may never.” Hardly a reliable diagnostic criteria.
  3. These children are ill and should be taken to see a doctor.
  4. Ditto. It would be interesting to discover if gut problems are more prevalent in autistic children and, if so, why. But in epidemiological studies where full health checks are done on all the autistic children who are identified, they have found the same rate of gastro-intestinal problems as in non-autistic children. Kirby here seems to be equating diarrhoea with smearing. Others who have commented on Kirby’s blog have pointed out that problems with smearing are unpleasant but they pass. They make a lot of other important points as well. Please read.
  5. Escape artists. They have always been with us. Take Gabriel. He is non-verbal, still not toilet trained and in residential care. And he will be 30 next year. That sort of blows away Kirby’s hunch that, “It can only be attributed to radical changes in our environment over the last 10-20 years.” Gabriel’s mum, Kate Rankin, wrote a book about him. I met her at a book signing and she is a very nice lady.
  6. Harming self and others is a common problem among autistic children who get into a rage or are frustrated by our inability to understand what they mean. Teaching effective communication skills helps. Teaching non-autistics to listen and learn from autistics also helps. Even the so-called “neurodiverse” have problems with people not listening or not understanding their needs. Read Ballastexitenz‘ latest on what happens when an apparently “low functioning” member of the “neurodiverse” is disregarded on a visit to the ER.
  7. He is talking about autistic kids here. And many of Kirby’s “neurodiverse” had similar childhoods. It was worse for a lot of them because they did not get a diagnosis. It was not that they were mislabeled as quirky or nerdy. They were totally misunderstood. When I was at that book signing with Kate Rankin I also met Gunilla Gerland. Her book about growing up with undiagnosed autism, A Real Person, disposes of the myth that the “neurodiverse” have an easy ride of it and have nothing in common with their more severely autistic brethren. And if they did get a diagnosis it was for a psychiatric disorder they did not have. Then they were not only mis-diagnosed. They were also mis-treated with psychiatric drugs they did not need. The kids Kirby is talking about are also being mis-treated. This time it is chelation for their non-existent mercury poisoning. Kirby’s book and its attendant publicity has doubtless led many other parents down this path. His book truly is “Evidence of Harm.”

So Kirby is trying to divide articulate and educated autistic adults from the rest of the autistic spectrum, who, on the basis of a journalistic hunch, are to be reclassified as suffering from Environmentally-acquired Neuroimmune Disorder. We do not know know what causes this, although Kirby, as  befits an altie, chelation shill, still insists that mercury is “a logical candidate.”

Kirby’s message is to be thankful for being educated and articulate and to abandon those less fortunate autistic brothers and sisters to the likes of Generation Rescue and Safe Minds. Divide and rule anybody? If Kirby expects us to accept this nonsense I have a hunch that he may be about to experience some real vilification.