There is an epidemic of vaccine-induced autism. Must be, we’ve been hearing this for about 10 years. During that time, many datasets have been manipulated to “prove” the epidemic. The two datasets that come to mind most readily are the U.S. special education data (IDEA data) and the California Department of Developmental Services data (CDDS). Neither were intended for true epidemiology.
That intro should be a warning: be prepared for more armchair epidemiology. Interested in the short answer? A new dataset is out that just doesn’t fit the idea of an “epidemic” of vaccine induced autism. No huge increases in autism counts.
The new dataset available is the 2007 National Survey of Children’s Health. The NSCH data includes questions about autism. So it should come as no surprise that it was spun into support for the “epidemic” already.
As a bit of background, let’s start with the US special education data. It’s a favorite dataset for those pushing the epidemic. Here’s a graph hosted on the Thoughtfulhouse website (click to enlarge):
Wow. That’s an epidemic. 16 year olds have an “incidence” (their word) of 0.4 per 10,000 while younger kids are at nearly 20? That’s an increase of 50 times. Impressive. Until we look at the NSCH data.
By coincidence the Thoughfulhouse data are from 2007, the same year as the NSCH data. What happens if we plot the NSCH data like the graph above? Again, click to enlarge. Sorry, I couldn’t format it to look just like the ThoughtfulHouse graph.
Doesn’t even look close to the data on the Thoughtfulhouse website. First, the “incidence” numbers for around age 16–0.4 for ThoughtfulHouse’s graph, 93 for the NSCH data. I wanted to graph the data on the same graph, but the newer, NSCH numbers just dwarf the IDEA numbers that ThoughfulHouse used.
Besides the difference in overall magnitude, what about the “epidemic”. What about the huge increases in autism “incidence” or “prevalence”. Numbers like 273% increase, or more, in autism are commonly quoted for the increase in autism diagnoses in the 1990′s. Well, those increases just aren’t observed in the NSCH data. Keep in mind, the 17 year olds in the NSCH data graph were born in 1990. There just isn’t the dramatic increase in an autism count in those data.
There is a a much smaller trend of increased autism count when moving from about age 17 down to about 12. The “incidence” increasing by about 40%. That’s a big number. Not hundreds of percent, but a big number.
The “incidence” goes down for younger kids–which must be partially or completely due to the average age of diagnosis being about 5. There is at least one blogger who is “sparking the debate” that this could be a sign that the removal of thimerosal has resulted in lower autism counts. The same blogger has stated at different times that we should have already seen any drop in the CDDS data and, later, that we won’t be able to see any trends until sometime well past 2010. That’s covering your bases! Either we saw it already, we are seeing it now, or we need to wait until the future to see it.
But, back to the NSCH data. Pretty much, those data are flat for birth year 1995 to 2003. Noisy but flat. That’s when the “epidemic” was in full force.
Or, another way to put it–there is no good evidence of an epidemic in the NSCH data.