This morning I received the following e-mail from Jennifer:

The above article was quite comprehensive and thoughtful but a few things haunt me. One is the fact that just because thimerosal was removed in around 2003 does not mean there will be a neat distinction in the numbers of autism (presuming thimerosal is the cause-some even see it as a symptom now of autism rather than the cause). This could be for many reasons,  including:

using up of thimerosal stocks already in existance up until the expiry date.
flu shots or multi-dose vials (containing mercury) could still be in use.
pregnant ladies are actually given flu shots and these may contain mercury
immigrant children ( from countries where thimerosal is not removed) may move to areas and be inluded in epid. studies
Also, you do not mention many shots at once and the lack of safety studies in regard to this.
Also,also, recently the mumps portion of the MMR was reduced. It was quadrupled in 1990 from what it was. This may also play a role in autism development.
What about all the kids with seizures and asthma these days. Why is MSG in the shots. EWWWW

I frequently receive similar e-mails, and similar questions appear in the comments of this blog whenever I write on the issue of vaccine and autism.  Jennifer touches on many of the current points in the moving target of anti-vaccine propaganda.

The “above article” she is referring to is Fear Not:Vaccine do not Cause Autism, which I wrote in June of 2005. While this was a fairly detailed article, it was far from comprehensive. The issue of vaccines and autism is very complex, with many relevant published studies. The article was more of an overview of the controversy. It is no also three and a half years out of date.

Here is a more recent article I wrote on the topic for Skeptical Inquirer – The Anti-Vaccine Movement, written in October 2007. It contains more information, but also is now more than a year behind the times. Of course, this blog contains many more entries on the vaccine and autism issue.

Here is an expanded version of my brief answers to Jennifer’s specific questions:

– using up of thimerosal stocks already in existance up until the expiry date.
A published inspection of 447 pediatric clinics and offices found only 1.9 percent of relevant vaccines still had thimerosal by February 2002 (Centers for Disease Control and Prevention Advisory Committee on Immunization. 2002. Practice Records of the meeting held on February 20–21, 2002, Atlanta Marriott North Central Hotel.) Those remaining few vaccines would have soon expired. So we now have a reliable 7 years after the removal of thimerosal without any decrease in the rate of increase of autism diagnoses, let alone the absolute decrease predicted by the “mercury militia.”

– flu shots or multi-dose vials (containing mercury) could still be in use.

Flu shots are optional, and even if children get flu shots thetotal dose of thimerosal from them would be much smaller than the maximal dose in the schedule in 2001. Some states, like CA, banned thimerosal containing vaccines, and many flu shots come without thimerosal. Of note, the primary source of data for the increase in autism diagnoses comes from CA, where flu vaccines do not contain thimerosal. The bottom line is this – toxicity is all about dose; the original argument for a link between thimerosal and autism was that both were on the rise in
the 1990’s, but now we have 7 years after thimerosal was dramatically reduced and the autism numbers have continued to rise without a blip. This is fatal to the thimerosal hypothesis.

– pregnant ladies are actually given flu shots and these may contain mercury

A 2007 study (Miles, J.H., and T.N. Takahashi. 2007. Lack of association between Rh status, Rh immune globulin in pregnancy and autism. American Journal of Medical Genetics, Part A1. 143(13):1397–407.) looked at the issue of exposure to mercury and vaccines during pregnancy and found no correlation with autism.

– immigrant children (from countries where thimerosal is not removed) may move to areas and be inluded in epid. studies

The data does not support this hypothesis. The number of immigrants with autism (while this is a separate and interesting question) does not account for the rise in autism diagnoses in the US. For example, the recent UC Davis study (even though I disagree with their conclusions) eliminated immigrants from the data base and showed they represented a very small number.

– Also, you do not mention many shots at once and the lack of safety studies in regard to this.

That is simply an anti-vaccine myth. Vaccines are tested both individually and as part of the overall schedule, including as multi-shots.Vaccines are tested, in fact, much more than drugs need to get FDA approval, by about an order of magnitude. Further, vaccine safety is monitored by the CDC.

– Also, also, recently the mumps portion of the MMR was reduced. It was quadrupled in 1990 from what it was. This may also play a role in autism development.

Numerous studies show no correlation between MMR and autism (MMR never contained thimerosal, btw). Vaccine constituents are monitored and tweaked as new evidence comes in. There is nothing sinister in this. This is nothing but anomaly hunting on the part of anti-vaccine
cranks who then try to imply sinister implications to facts, without putting them into any context.

– What about all the kids with seizures and asthma these days. Why is MSG in the shots. EWWWW

Asthma is on the rise. This is an area of ongoing research. So far there is no reason to link this to vaccines.

Seizure frequency rises and falls over the years, without any clear trend. Rates were higher in the 1990’s then they are today, although the last few years have seen a rise. There are rare reactions to vaccines, which can include seizures, although this is mostly due to febrile seizures – vaccine reactions can cause fever, and the fever can trigger a seizure is some children. A CDC study found “1 additional febrile seizure for every 3,000-4,000 doses (of MMR) administered.” It is important to note that febrile seizures does not equal epilepsy, and most children with febrile seizures do not continue to have seizures and do fine. In other words, there is no permanent harm.

Of note, an extensive CDC study found no correlation between vaccines and 43 measures of neurological development.

MSG is used in the manufacturing process of a few vaccines as a stabilizer. The overall dose is tiny – and again, there is no data linking this to any neurological disorders.

Conclusion

I don’t know if Jennifer is anti-vaccine, or is just reacting to some confusing and concerning information she picked up on the internet – the fruits of the anti-vaccine misinformation machine.   But what we see here is a manifestation of the basic strategy of the antivaccinationists – throw whatever they can against the wall, make it sound as sinister as possible, and hope that something sticks. At the very least it generates fear – it creates the uneasy feeling that something must be going on.

The “EWWWW” comment is pithy and insightful – that raw emotional disgust at the notion that there are weird chemicals in vaccines is exactly the reaction desired by the antivaccinationists. But there are chemicals in everything – the real question is, are they safe at the doses of exposure.

A critical examination of each point shows it to be invalid or a gross misrepresentation of the facts. But no matter how often we clean up their mess, the antivaccine movement will continue to find more stuff to throw against the wall.