MMR vs Autism – Amateur Epidemiology

Once again, the headlines declare, “No link between autism and MMR vaccine“.

The story, however, is a different matter:

The study, published on Tuesday in the Archives of Disease in Childhood, found no evidence of any abnormal biological response from the shot that could point to a link between the vaccine and autism.

Hmm… an absence of evidence of a link does not mean evidence of the absence of a link.

“This study really supports the view these are safe vaccines,” said David Brown, a researcher at Britain’s Health Protection Agency who worked on the study. “The evidence is now so solid there really isn’t a need for further studies here.”

Same old guff that’s been said at the conclusion of a number of other studies, all of whom appear almost deliberately to have been set up to provide statistics that imply the absence of a link. Perhaps the most famous is the “Danish study”. The study demonstrated that there was actually a higher risk of autism among those who did not receive the MMR. What was not noted in that study is that it occurred at a time when the suggestion of an MMR / autism connection was big news, so those children already at risk of autism were more likely to turn up in the group of children whose parents refused to give their children MMR. A self-selecting study is no study at all.

As Jackie Fletcher of JABS puts it:

It is making a leap from having the actual data on the antibodies and saying MMR does not cause autism.

Persistent measles infection is only one of the theories on why there appears to be a connection between the MMR vaccination and autism – my favourite explanation by far is that there are children at risk from autism, and that every time their bodies are put under significant stress (such as the high fevers associated with vaccination), there is a chance that a regression will be triggered. That’s a very loose theory, granted, but there are others – one very interesting suggestion is that the study quoted in today’s news articles focuses on children aged 10 – 12, and if those children had persistent measles infection from vaccination at or around 2 years old, it would not be evident from antibodies in the bloodstream, but in the spinal column. I don’t know how true that claim is, though.

Now, you might say that the studies that have suggested a link between MMR and autism are also biased in their construction, and designed to give the results that would imply such a link.

I agree.

An appropriate study, in my opinion, would be to select candidates who are “at risk” from autism – where a member of the family has autism, or where a member of the family is an engineer, or where there is higher-than-average incidence of college education – and follow their babies from birth through age five or so. Some of the group would be given the MMR in one visit, as is the current method of operation, others would be given separate Measles, Mumps and Rubella shots in three visits, several weeks apart. A little tricky to do this as a double-blind study, but not impossible – the MMR patients would simply receive a saline shot instead for two of their three visits.

Such a study would get over the issue that, with an incidence rate of 1 in 150, and only a fraction of that being suggested as related to MMR vaccination, autism causes disappear into statistical noise; such a study also allows for possible weighting factors to be recognised and balanced (by assigning study members such that particular combinations of weighting factors appear more or less equally in each cohort), in a way that has not been possible, or not been tried, with other studies.

While there are many irrational views on both sides of this debate, sadly it seems as though these are the views that make the loudest noise.

A scientific approach to this discussion has not yet been considered, in my opinion.

Most parents of autistic and at-risk children I have spoken to (and granted, that’s not in the hundreds that would be required for a good sample) are not looking to make the choice between MMR or not vaccinating their children – they are artificially limited by the government to making that choice. The lack of availability of individual vaccines for Measles, Mumps and Rubella makes the choice one of “MMR and possible-to-likely autistic regression” versus “possible measles, mumps or rubella infection – maybe in someone else’s kid”. I think that particularly when it comes to illnesses like Rubella, where the risk is to the in-utero fetus of an infected mother-to-be, perhaps we ought to consider whether it is safer to vaccinate girls as they approach their fertile years, rather than vaccinating everyone a year or two after birth, in an attempt to provide “herd immunity”.

Another thing I’m not looking for is to blame all (or even most!) cases of autism on the MMR vaccine, or thimerosal, or any of a number of other causes. There are so many stories of autistic onset, from the kid who “everyone could see he was different from the moment he was born”, to the kid who develops normally into a babbling toddler and then suddenly shuts up and retreats into his mental cocoon over the course of a few days. Clearly, there’s a genetic component that at least creates a susceptibility, but for something to happen so suddenly, and so coincidentally “on time”, it seems like there has to be an environmental component that acts like a trigger.

With the government continually feeding us crap science, and no physical method to reliably screen for a majority of autism cases, it’s no wonder many parents feel like emulating their children at their worst autistic moments, repeatedly banging our heads against the wall, because it’s better than not knowing why our heads hurt.

Autism Screening at 18 months and 2 years

I’m excited by the news that the American Academy of Pediatricians is recommending that all children be screened at their regular 18 month and 24 month checkups for autism.

As regular readers will know, my son was diagnosed with Asperger’s Syndrome, at age five, having been in a special education programme (but without a specific diagnosis) since the age of three. Thanks to the various efforts of therapists with specialities in speech, occupational and physical therapy, social development and other skills, for the most part, you wouldn’t think he’s any different from any other child.

The last kid in his neighbourhood to ride a bicycle without training wheels at age 7, he now rides a unicycle. There are many other examples where he has proven not only to be capable of those things that he needed help to learn, but also that he can excel.

All this because of interventions applied as early as we could get them, sometimes requiring us to fund expensive therapy ourselves, because our health insurance company states without a hint of irony that the brain does not develop past the age of seven. My thought is that this policy was drafted by someone who dropped out of school at that age, and it’s certainly out of line with current neurological science, particularly the theory of brain plasticity.

“Early intervention” is a strong rallying cry among supporters of autistic children – but it is equally important to recognise that there is no age beyond which an autistic person cannot be helped – and no age beyond which autism is “grown out of”

I should note that I’m not an official source of information, and I’m only going off what I have noticed when interacting with autistic spectrum (AS) and neurotypical (NT) children. Here are some of the signs I think you should watch for in your own children:

  • Pointing – does your child point to show you stuff? [Pointing to something that he wants you to get is common, even among AS kids, but pointing to show you something cool, that’s something NT kids do.]
  • Speech – is your child late to speech-related milestones? Babbling, single words, simple sentences – these all come in a logical progression for NT kids, but for AS kids, they may come late, steps may be skipped, or there may be a regression. An AS child may have a couple of words early on, then stop speaking altogether, later speaking full sentences without first building simple sentences.
  • Social play – does your child play with other kids, or just play near them? In the park, an AS child will play on the same swings and roundabouts as everyone else, but will interact less with the children on those toys.
  • Wheels – AS children are typically interested in wheels and spinning things of all types. [A story goes that Albert Einstein saw his sister when she was first born, and said “It’s all very well, but where are its wheels?”]
  • Physics Experiments – Kids with AS generally have an interest in finding out how things work, whereas NT kids are likely to be more interested in learning how people interact.
  • Obsessive behaviour – one classically autistic behaviour in children is to line up toys – straight lines, often ordered by some characteristic – colour, size, number of wheels, etc.
  • Lack of imaginative play – this doesn’t mean that AS kids don’t invent or imagine with their play, but by and large, a toy car will always be a toy car, and not a duck or a boat or an airplane. Pick up a toy car and pretend it’s an airplane, and an autistic child may very well express irritation at your stupidity in thinking it’s not a car. Similarly, even a child with little or no expression of language will get irritated if you point to a page in a book and say “this is a cow”. It’s not a cow, after all, it’s a _picture_ of a cow.
  • Lack of balance, clumsiness – particularly when an autistic child is distracted, there may be an inability to tell where the body and its various parts are. This is known as “proprioception”. In combination with typically low muscle tone, this can leave the distinct impression that the AS child is more clumsy than his peers.
  • One or more parent has at one time or another been described as “engineer”, “mathematician” or “scientist”. Seriously, in many support groups I’ve predominantly met parents who match this description.
  • Inflexibility – when you say “we’re going in five minutes”, if your child throws a tantrum because five minutes have gone by, and you’re not quite ready, or if you can’t go to the park today because it’s raining, or the cable is out and they can’t watch their favourite television show.
  • Transition trouble – do problem behaviours mount when you move from one task to another? Does your child get inconsolably distraught when a movie or playtime is over?
  • Shutdown on overload – does your child appear completely non-responsive at times? At one time, we wanted to test Colin’s hearing, because he wouldn’t respond to his own name shouted from across the room. Other times, it was clear that his hearing was super-sensitive, as he would respond to his name whispered from across the house.

Make sure to compare your child with other children his own age, and watch for the milestones that you’ll find listed everywhere in the parenting books. I’ve met autistic children with only a handful of the above signs, and some NT children who had several – but as a rough and ready guideline, I hope you’ll find this set useful.

Above all, listen to your gut. Your pediatrician is an expert on kids on average and in general – you are an expert in your child, and you know far more on that subject than any pediatrician. If your child’s behaviour shows a significant departure from those of other kids his age, push for an explanation. If you still have concerns and your pediatrician appears simply to be calming your fears, insist that your child be tested; visit another pediatrician if you must, get a second opinion, and keep trying to explain and accept, but work with, your child’s differences.