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Thimerosal Linked to Autism in Confidential CDC Study

     Controversy is mounting regarding the Center for Disease Control's (CDC) Thimerosal Vaccine Safety Data-Link Study (VSD) presented to the public at the July 15, 2001, Institute of Medicine (IOM) meeting on "Thimerosal-Containing Vaccines and Neurodevelopmental Outcomes." Thimerosal is the mercury preservative used in vaccines and other biologics. The CDC study evaluated nuerodevelopmental injury and cumulative exposures to Thimerosal at one and three months of age by studying the health records of over 100,000 children at four HMOs.
     The organization SAFEMINDS (Sensible Action for Ending Mercury-Induced Neurological Disorders) has obtained an earlier, confidential February 2000 version of the VSD study through the
Freedom of Information Act, as well as transcripts from a scientific review of this earlier study, which took place at Simpsonwood Retreat Center in Georgia. Serious disparities exist between the
neurodevelopmental outcomes of the two different versions of the study. For over a year, SAFEMINDS and Congressman Dan Burton (R-Indiana) have been requesting the VSD raw data from the CDC for
independent review. So far their requests have been denied.
     The Texas firm Waters and Kraus leads the consortium of 25 law firms in as many states in the first civil suit brought against vaccine manufacturers and alleges that the February 2000 confidential version of the VSD study clearly demonstrates "an exposure to more than 62.5 micrograms of mercury within the first three months of life significantly increases a child's risk of developing nuerodevelopmental orders such as speech and language delay, autism, stuttering, and attention deficit disorder." In fact, the study
indicates that children at this exposure level are more than twice as likely (2.48) to develop autism as those not exposed. Waters and Kraus note: "Courts of law have generally upheld that a relative risk of 2.0 or higher is sufficient to substantiate that a given exposure causes disease.

   When the VSD study was presented at the July 2001 IOM meeting, the relative risk of autism had been reduced to 1.69. According to Mark Blaxill of SAFEMINDS, all previous versions of the study had used the same dataset. Yet for the version presented at the IOM meeting had an additional 34,334 children added to the database. The majority of the additional children were added by altering the
inclusion criteria, as well as by updating the HMO data cycle by adding an additional year, 1998. The additional children were too young to have been diagnosed autistic since they were just turning two at the time the analysis was performed. Autism is diagnosed on the average at 44 months.
     When the author of the VSD study, Tom Verstraeten, first presented the confidential version for scientific review by a panelof experts at Simpsonwood in June 2000, he said, "One thing that is for sure, there is certainly an under-ascertainment of all these [neurodevelopmental disorders] because some of the children are just not old enough to be diagnosed. So the crude incidence rates are probably much lower than what you would expect because the cohort is still very young."
     The FDA and EPA called for the removal of mercury in infant vaccines beginning in 1999. At that time, vaccine manufacturers agreed to have thimerosal-free vaccines available at the beginning of 2001 and later offered voluntary exchange for all remaining thimerosal vaccines still on the shelf. In July of 1999, the American Academy of Pediatrics (AAP), under the leadership of pediatric vaccinologist Dr. Neal A. Halsey, met with officials from the CDC to ask that the birth dose of Hepatitis B be pushed back as far as six months of age. The CDC and members of its National Immunization Program (NIP) refused, arguing that there was no evidence of harm done. They didn't want to undermine public
confidence in the vaccination program. After much negotiation, the CDC released an ambiguous and weak statement that suggested that in certain low-risk populations physicians could wait until babies were two months of age before they administered their first hepatitis B vaccine.

The Advisory Committee on Immunization Practices (ACIP), the CDC committee that recommends the vaccines for the Childhood Immunization Schedule, has yet to state a preference for thimerosal-free
vaccines. It was the ACIP that approved of the additions to the Childhood Immunization Schedule of hepatitis B and Hib in the late 1980s and early 1990s, two thimerosal-containing vaccines that pushed
infant ethyl mercury exposure levels far above any existing federal methyl mercury exposure guidelines.
At the June 2000 Simpsonwood meeting, the following comment was made by a participant, "This association leads me to favor a recommendation that infants up to two years old not be immunized with
thimerosal-containing vaccines if suitable alternative preparations are available… Forgive this personal comment, but I got called out at eight o'clock for an emergency phone call, and my daughter-in-law
delivered a son by C-section. [This is] our first male in the line of the next generation, and I do not want that grandson to get a thimerosal-containing vaccine until we know better what is going on…"
SAFEMINDS, a group founded by parents of children suffering from what they know to be mercury-induced neurological disorders, believes that everybody's child should have had this knowledge and option in June of 2000.

Just how much thimerosal is too much for an infant? It depends on whom you ask. Chair of the IOM's Immunization Safety Review Committee, Dr. Marie McCormick, gave assurances to the public last October that it would be rare for any child who follows the vaccine schedule to exceed federal guidelines for methyl mercury exposure. Yet the confidential CDC study found that "the majority of children in their cohort exceeded the EPA limits at one and three months of age." The EPA guidelines allow for 0.1 mcg per kilogram of body weight per day. Depending on her weight, a three-month-old infant who received 62.5 micrograms of mercury in one day would exceed the EPA guidelines upwards of 78 times. And, as researchers were quick to point out at the July IOM meeting on thimerosal, the EPA's safe limit is based on gradually ingested methyl mercury via fish consumption. It was never meant to be used as a safety limit for injected bolus doses of ethyl mercury, which permeate the blood-brain barrier.
According to Dr. Boyd Haley, head of the chemistry department at the University of Kentucky, and an internationally recognized researcher on the toxicity of mercury compounds, says no amount of thimerosal is a safe amount. He says, "It is well known that infants do not produce significant levels of bile or have adult renal capacity for several months after birth. Bilary transport is the major biochemical route by which mercury is removed from the body, and infants cannot do this very well." Haley adds that thimerosal is more toxic than mercury and that "giving a ten-pound infant a single vaccine in a day is the equivalent of giving a 100 pound adult 40 vaccines in a day." He goes on to say, "We are not talking about causing death; we are talking about causing autism. As a scientist, you have to ask yourself, what's the most obvious neurotoxin that these children are being exposed to that could cause this? Thimerosal."