But even in his broken promise blog post, Dr. Gorski admits a flaw in the database used by Schechter and Grether:

“The weaknesses of the CDDS is that its data is derived from an administrative system that was designed to track enrollment and fiscal data and is not as well suited to measuring the occurrence of developmental disabilities in the population.”

Unlike the California Department of Developmental Services, however, the Alabama Autism and Developmental Disabilities Monitoring (ADDM) Network is designed for just that purpose of measuring the occurrence of autism and developmental disabilities, hence the name.

And what has happened in this system's most recently reported prevalence of autism in eight-year-old children from 2008 compared to eight-year-old children in 2006? A 20% decline in prevalence – the first statistically significant decline to have occurred anywhere in the US CDC's ADDM Network. And what was Dr. Gorski's promise seven years ago?

“If rates fall by less than 50% but still inarguably statistically significant, I will concede that this would be pretty good epidemiological evidence that there might be a connection...”

Dr. Gorski has yet to make good on this promise, even though he stated in an April 2, 2012 blog post on the latest ADDM autism prevalence report (which included the declining in Alabama):

“If mercury in vaccines were a cause of autism, we’d expect to start to see a decline in autism prevalence.”

He then immediately contradicts himself with the following statement:

“Even if the cause of this apparent increase in autism prevalence is better detection, broadening of the diagnostic criteria, and increased awareness, this report is not good news for those who believe that mercury in vaccines cause autism.”

The fact is, this report is “good news” for “those who believe that mercury in vaccines cause autism” because it does show a decline in autism prevalence – albeit in one state. Who this report is not “good news” for are people like Dr. Gorski. Is he going to argue that “this apparent decrease in autism prevalence is worse detection, restricting of the diagnostic criteria, and decreased awareness” and that this phenomenon only occurred in Alabama?

Of course, that argument does not make sense, especially for a state like Alabama where the autism prevalence in eight-year-olds, prior to the drop in 2008, saw the second-fastest increase in prevalence of any other state in the system. Alabama's Gross State Product for 2008 has increased since 2006 and the poorer ADDM client state of South Carolina saw a continued increase, so he could not argue the drop is due to economic factors. So what would suddenly cause such a dramatic change to occur? The year 2000 was the first birth year reported in ADDM after the 1999 joint statement by the American Academy of Pediatrics and the Public Health Service issued the call to remove thimerosal from vaccines as soon as possible. No reliable thimerosal estimates exist, but according to the Council of State Governments, thimerosal was not completely out until “early 2004.” Was Alabama the first reported ADDM client state where thimerosal-free vaccines became widely available?

Health Maintenance Organizations cover specific geographic areas and purchase vaccines in bulk for given years. So the age and place of residence of a patient could certainly impact the types of vaccines that patient receives, including whether or not those vaccines are preserved in thimerosal. By matching participants in the Vaccine Safety Datalink Project with and without autism on the basis of shared birth year and HMO/geographic region, the CDC was effectively able to erase any elevated risk for autism associated with thimerosal exposure; it’s called over-matching. Even though the CDC admits that changes in thimerosal exposure are unknown, let alone for certain states, a decrease in autism starting in one particular state before others is the type of trend one can expect to see in autism prevalence if indeed thimerosal causes autism.

What makes Alabama's reported prevalence all the more valuable is that the ADDM Network only includes a small fraction of US states, and unlike Alabama, not all states in ADDM are consistently reported. Some are removed permanently, others are newly added, and then there are states that were removed from the network only to be added during later years. So the ADDM Network overall is not dealing with a consistent population of people, which makes consistently tracked prevalence from states like Alabama the most informative and the fact that the autism prevalence decreased in Alabama when it did particularly damning of thimerosal. Additionally, prior to the CDC’s 2008 autism prevalence report, Alabama’s prevalence was increasing faster than all but one other state in the network. Had its prevalence continued to grow at the same trajectory, instead of declining in 2008, the state prevalence would have been roughly approximate to the average prevalence of all the states in the network.

Although Dr. David Gorski broke his promise to concede that this decrease in autism prior to both 2015 and even 2010 is “pretty good epidemiological evidence that there might be a connection,” he still implicitly said the connection is plausible.

Add this quote of his to former CDC director Dr. Julie Gerberding conceding on CNN that vaccines cause autism, millionaire vaccine industrialist Dr. Paul Offit admitting vaccines cause autism spectrum disorders in his interview with Medscape, former CDC Epidemic Intelligence Service Officer Dr. Thomas Verstraeten saying in email to his colleagues that he would conclude thimerosal causes harm, namely autism, former AAP president Dr. Renee Jenkins going so far as saying on Good Morning America that the benefits of vaccines far outweigh  risks since vaccines cause autism in less than three percent of all children and even Dr. Gorski’s blogging buddy Dr. Steven Novella inadvertently linking more vaccines to the onset of autism. The result is a growing number of doctors from CDC, AAP and even the vaccine industry conceding that there is proof or at least “pretty good evidence” that vaccines and vaccine ingredients cause autism, like the mercury-based neurotoxic vaccine preservative thimerosal.

Jake Crosby has Asperger Syndrome and is a contributing editor to Age of Autism. He is a 2011 graduate of Brandeis University with a BA in both History and Health: Science, Society and Policy. He currently attends The George Washington University School of Public Health and Health Services where he is studying for an MPH in epidemiology.