Robert Schechter 1 , Judith K Grether
Arch Gen Psychiatry. 2008 Jan;65(1):19-24.
doi: 10.1001/archgenpsychiatry.2007.1.
| AAP: Autism client data from the California Department of Developmental Services were analyzed between 1995-2007. Thimerosal was removed from recommended childhood vaccines after 2002, but autism cases continued to increase each quarter. The data do not show a decrease in autism in California even after trace levels of thimerosal were removed from nearly all childhood vaccines. Data did not support the hypothesis that exposure to thimerosal during childhood is a primary cause of autism. |
Abstract
Context: Previous analyses of autism client data reported to the California Department of Developmental Services (DDS) have been interpreted as supporting the hypothesis that autism is caused by exposure to the preservative thimerosal, which contains ethylmercury. The exclusion of thimerosal from childhood vaccines in the United States was accelerated from 1999 to 2001. The Immunization Safety Review Committee of the Institute of Medicine has recommended surveillance of trends in autism as exposure to thimerosal during early childhood has decreased.
Objective: To determine whether trends in DDS autism client data support the hypothesis that thimerosal exposure is a primary cause of autism.
Design, setting, and patients: Study of time trends in the prevalence by age and birth cohort of children with autism who were active status clients of the DDS from January 1, 1995, through March 31, 2007.
Main outcome measure: Prevalence of autism among children with active status in the DDS.
Results: The estimated prevalence of autism for children at each year of age from 3 to 12 years increased throughout the study period. The estimated prevalence of DDS clients aged 3 to 5 years with autism increased for each quarter from January 1995 through March 2007. Since 2004, the absolute increase and the rate of increase in DDS clients aged 3 to 5 years with autism were higher than those in DDS clients of the same ages with any eligible condition including autism.
Conclusions: The DDS data do not show any recent decrease in autism in California despite the exclusion of more than trace levels of thimerosal from nearly all childhood vaccines. The DDS data do not support the hypothesis that exposure to thimerosal during childhood is a primary cause of autism.
| “This study was supported through the California Department of Public Health.” |
14Studies.com
The entire study is based on the false premise that children’s vaccines no longer contain mercury. But, may be helpful in raising the larger point that mercury is not the sole problem with vaccines, and it looked at a lot of kids in a reliable state for data, California. Conflict is high: lead author is in charge of California’s immunization program.
Actual Question This Study Asked & Answered:
Q: Has the rate of autism in California decreased since thimerosal was “removed” from vaccines?
A: No.
Did the study look at unvaccinated children?
No.
Conflict of Interest (from the study itself):
“This study was supported through the California Department of Public Health.”
The lead author works in the immunization branch of the California Department of Health, his job is to give vaccines to children.
Ability to Generalize:
The study is so fatally flawed, there is nothing to generalize about. The study assumes that thimerosal was no longer in California’s vaccines for kids after 2002 which is simply a false assumption (see criticisms below for more detail). However, the study does make the point that autism continues to grow, which calls into question the entire vaccine schedule, rather than just one ingredient.
Post-Publication Criticism:
High, because the assumption of the study was flawed. Moreover, the study never looked at exposure data by child, it simply generalized and estimated.
Scoring (Out of 40 possible points):
Asked the Right Question: 1
Ability to Generalize: 0
Conflict of Interest: 0
Post-Publication Criticism: 0
Total Score: 1
Choice Excerpt from the Study:
“In the absence of exposure data for individuals or the population, we adjusted published estimates of maximum thimerosal exposure for infants and toddlers6 to reflect subsequent recommendations for influenza vaccine and the fact that the third doses of DTP, DTaP, Hib, and hepatitis B virus vaccines usually have not been recommended before 6 months of age. Based on these estimates, children aged 3 to 5 years (Figure 3) reported to the DDS since the first quarter of 2004 are assumed to have reduced exposure compared with children aged 3 to 5 years reported from 1995 through 2003.”
Meaning: We don’t have actual thimerosal exposure data by child, and we also did not consider if any of the mom’s received mercury-based vaccines while pregnant, a practice that was recommended starting in 2002 (for the flu shot).
Guest Critic #1: Boyd Haley, Ph.D. Professor of Chemistry, University of Kentucky
RESPONSE TO 2008 R. SCHECHTER AND J. GRETHER PUBLICATION ‘CONTINUING INCREASES IN AUTISM REPORTED TO CALIFORNIA’S DEVELOPMENTAL SERVICES SYSTEM’ WHICH ADDRESSES CALIFORNIA DEPARTMENT OF DEVELOPMENT SERVICES DATA ON EVALUATION OF THE RELATIONSHIP BETWEEN THIMEROSAL AND AUTISM
8 January 2008
by Boyd Haley, Professor of Chemistry, University of Kentucky, Lexington, KY
We should all consider that there are two top priorities in the vaccine/autism issue every American should be concerned with. We need to develop a safe vaccination program, and we need to find the cause of autism and eliminate it if possible. I have been a strong proponent of investigating thimerosal as the casual agent for autism spectrum disorders based on the biological science that shows thimerosal to be incredibly toxic, especially to infants. I know of nothing remotely as toxic as thimerosal that numerous infants would be exposed to before 3 to 4 years of age. Below I present several comments regarding this issue and the 2008 Schechter-Grether study that I think are relevant. Mainly, while the Schechter-Grether study appears to be a well done study it suffers from the fatal flaw of assuming that thimerosal was removed to safe levels in vaccines by 2002. They also cut a fine edge as to time when a significant drop in autism rates would be expected. Further, no study exists that proves our vaccine schedule alone is safe, let alone the current one that still exposes infants to thimerosal, a concern they do not address. The alarming concern is that these authors seem more involved at providing material saying thimerosal is safe than they are concerned with the obvious fact, openly presented in their own data on autism rates, which strongly indicated that increased rates of autism started with the CDC mandated vaccine program. References to support the comments are readily available in many recent publications.
- Autism was not a known, described illness until about 1941-3, 8 to 10 years after the introduction of thimerosal and similar organic thiol-mercury compounds in biological mixtures used in medicine and other areas. This argues against autism being a genetic illness.
- In 1977, 10 of 13 infants treated in a single hospital by topical application of thimerosal for umbilical cord infections died of mercury toxicity. This same topical was used on adolescents without obvious ill effects which strongly supports the concept that infants are very susceptible to thimerosal toxicity.
- The recent increase (starting about 1990) of autism spectrum disorders correlated well with the advent of the CDC mandated vaccine program which increased thimerosal exposures with increased vaccinations. Due to its toxicity, thimerosal would have to be suspect for causing autism.
- As expected by science, extensive searching for a genetic cause of autism has not turned up a significant find that would explain the recent increased rate in autism. The latest genetic find, at best, might explain 0.5% of autism causation. Most agree that a genetic predisposition is likely (like those that lead to low glutathione levels), but that a toxic exposure is absolutely needed. Consider also, that this increased toxic exposure would have had to occur in all 50 states at about the same time as all states have reported similar increases in autism rates. Only something like the government recommended vaccine program fits this need for a time dependent, uniform exposure of a toxin throughout all the states.
- In the Schechter-Grether study it is implied or assumed that all thimerosal containing vaccines were gone by the end of 2002 due to their expiration dates. I don’t think this is a valid assumption. I have talked to mothers who asked to see the vaccine inserts as late as 2004 and found thimerosal present as a preservative in infant vaccines being used in certain clinics. Also, in 2004 the influenza vaccine was recommended by the CDC for infants 6 months of age and older. It would appear as if a thimerosal free vaccine time-frame would be very hard to identify, if one ever existed. I have read that the average age of autism diagnosis is near 44 months of age. Therefore, while it does seem reasonable to expect a decrease in autism after 4 to 5 years of complete thimerosal removal, assuming a consistent diagnostic protocol was used, it appears this has not been accomplished. This means the Schechter-Grether study is likely somewhat premature in reaching the conclusions reported in that enough time has not passed for the expected decrease to occur and that they were quite optimistic in identifying the dates of thimerosal reduction and underestimate exposures occurring between 2002-4.
If, indeed, the complete removal of thimerosal from vaccines was not followed in an appropriate time by a decrease in autism then this would be solid proof that thimerosal was not causal for autism. However, thimerosal has not been completely removed from vaccines and thimerosal used at the original levels in the manufacturing of these vaccines with a trace amounts left in the vaccines when bottled. I don’t know what level a ‘trace’ is since it is not a term used in science to describe an actual amount. Some called the 12.5 micrograms mercury in the older vaccines a a ‘trace’ amount. Bottom line, the infants are still getting some level of thimerosal, a ‘trace’amount that is free and an amount of ethylmercury that is bound to the proteins that induce the immune response.
If vaccines are causing autism and it appears this is a strong possibility based on the California data and, if removing thimerosal added as a preservative really does not reduce the autism rate then the causation is much more complex.
Consider the possibilities that:
A. Autism may be caused by a thimerosal modified protein that sets off an immune response or causes some other biological reaction that can cascade with injurious effects. Since the vaccines are manufactured with thimerosal present in abundance it is quite likely that any cysteine containing proteins would be modified with ethylmercury. Removal of most of the free thimerosal (or just not adding it) would not decrease the level of any toxic modified protein produced during the vaccines production that might be causal. Removing the thimerosal added as a preservative would not decrease the amount of this ethylmercury modified protein in those vaccines with a ‘trace’ thimerosal levels.
B. That autism could be caused in susceptible individuals by very low thimerosal or ethylmercury modified protein exposures due to their genetic susceptibility or other factors (general health, gender). In this scenario the higher thimerosal exposures are not required and the induction of autism is not thimerosal concentration dependent at the old and new thimerosal vaccine levels, but just requires a significant exposure level that is met by the vaccines containing the lower a ‘trace’ amounts of thimerosal and past thimerosal levels in vaccine production processes.
Bottom line, if genetic susceptibility is involved then causation of autism may not increase linearly with increased thimerosal exposure. Causation may only require low thimerosal exposure or exposure to modified proteins. It is possible that the reduction of thimerosal as in the a ‘trace’ was just not enough to produce a safe vaccine.
Not all toxins work like alcohol and the old ‘a dose makes the toxin’ is not always correct. As long as they are used, the mere use of ‘a trace’ thimerosal in vaccines along with higher levels in the flu vaccine will always prevent a conclusive answer to thimerosal’s involvement in autism causation. What should be studied is the “no exposure” versus the “exposed” populations with regard to autism rates.
If indeed autism is rare among the non-vaccinated Amish populations, as reported by Dan Olmstead, I find it an amazingly oversight that the CDC and others responsible for infant health do not fund a study in this area.
This study could go both ways, if the Amish have autism rates identical with the rest of the population the argument would be over — neither vaccines nor thimerosal would be causal for autism, and I personally would argue in this direction. If, however, the autism rates in the Amish are exceptionally low then vaccines would have to be considered as a prime suspect in causation with the presence of the highly toxic thimerosal the main suspect.
If the results in the 2008 Schechter-Grether study hold up with time, and complete removal of thimerosal does not cause a drop in autism rates and the autism rates in non-vaccinated populations are low then something else in the vaccines would have to be considered the major causation factor for autism. However, without doing the non-vaccinated population studies there cannot be a conclusive statement either way about either vaccines or thimerosal as being causal for autism. The steadfast refusal of the CDC and others to support such studies being done is part of the reason that many parents, scientists and physicians have severe doubts about the sincerity of their efforts to resolve this issue. This is how I think, when I review a paper submitted for publication I always ask why an obvious experiment wasn’t done. The study of non-vaccinated populations is a very obvious experiment that the CDC and its supporters appear to refuse to consider. This makes me suspicious that this knowledge exists and is being suppressed because knowledge of the rate among the non-vaccinated population would answer many questions.
Finally, the Schechter-Grether study may be good news to the vaccine manufacturers and those who recommended and use the mandated vaccine program as it serves as manufactured uncertainty about the thimerosal involvement in autism causation. However, it presents a major concern to the parents and families of infants since it implies that our vaccines, even with most of the free thimerosal removed, may not be safe and that our CDC does not have a clue about what to do make them safe. Common sense would lead most to attack finding the cause of autism instead of trying to prove something besides thimerosal is causal. The major question is “are our vaccines causing autism?” — only comparing the non-vaccinated to the vaccinated will answer this question. Common sense would have lead to this comparison being done first and being done 10-15 years ago. In the recent past I have recommended that parents vaccinate their children with thimerosal free vaccines as I considered them safe. If Schechter-Grether are correct, and vaccines, but not thimerosal, correlate with increased autism rates, then I am in error assuming vaccines are now safer with regards to autism risk than they were 2000.
Guest Critic #2: Deirdre Imus Environmental Center for Pediatric Oncology
Statement on California Autism Study
In reviewing a new study published in the Archives of General Psychiatry, “Continuing Increases in Autism Reported to California’s Developmental Services System” (January 7, 2007),1 The Deirdre Imus Environmental Center for Pediatric Oncology finds the study’s conclusions premature and inconsistent with published clinical research.
Using epidemiological data from the California Department of Developmental Disabilities (DDS), researchers Schechter and Grether reviewed the trends in autism in conjunction with decreasing amounts of thimerosal ethyl mercury exposure. The authors concluded, “The DDS data do not support the hypothesis that exposure to thimerosal during childhood is a primary cause of autism.”
We do not believe this conclusion is supported by the methodology and results presented in the article. The study’s authors incorrectly cite how long mercury-containing vaccines remained in circulation in California and failed to account for the impact of the reintroduction of the mercury-containing influenza vaccine. The study also failed to provide evidence that thimerosal did not cause autism in a significant subset of children.
The American Academy of Pediatrics (AAP) and the Centers for Disease Control and Prevention (CDC) began recommending the influenza vaccine for infants and pregnant women in May 2002. This recommendation reintroduced significant amounts of mercury exposure in utero and again at 6 and 7 months of age.
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5102a1.htm
It should be noted that existing stocks of mercury-containing vaccines were not recalled; they remained on clinic shelves.
We also have no way of knowing precisely how much mercury remains in children’s vaccines today. Neither the FDA nor the CDC performs any oversight testing to validate the level of mercury currently remaining in children’s vaccines. Vaccine manufacturers report the amount of mercury in vaccines but we have no independent confirmation of those amounts. We are essentially expected to trust the manufacturers regarding mercury content in these vaccines. While “trace” amounts of thimerosal are still incorporated in several routine childhood vaccines, numerous studies have found very small amounts of mercury to be a potent developmental neurotoxin capable of causing the characteristics we see in children with autism. (Parran et al. Toxicol Sci 2005; 86: 132-140). Decades of published research have shown mercury to be particularly toxic to the developing fetus, infants and young children. Thimerosal is mercury and, as the AAP has noted, “Mercury in all its forms is toxic.”
The 2004 California law that would ban the use of mercury-containing vaccines for pregnant women and children under the age of three did not go into effect until December of 2006. The California’s DDS does not include children under the age of three years of age in their data. Because of the recommendation to give the mercury-containing influenza vaccine to pregnant women and young children, in combination with other “trace” amounts in other vaccines, it is clear that pregnant women and infants continued to receive mercury-containing vaccines. Therefore it is far too soon to leap to the conclusions made by the study’s authors.
The study fails to rule out that a subset of the population could have regressed into autism after inoculations with mercury-containing vaccines. If we are unable to exclude this possibility, and the subset is only 5% of the children diagnosed with autism, this could still represent thousands of children.
The authors’ reliance on strictly epidemiological data, while acknowledging the “absence of exposure data”, along with the failure to consider the toxicological significance of thimerosal documented in other studies, calls into question the study’s findings and the misleading conclusions reported in the media. The tripling of immunizations during the 1990’s, many of which contained mercury amounts that exceeded EPA safety guidelines cannot yet be dismissed as contributing to the increased prevalence of autism spectrum disorders in the United States.
Thimerosal may not be the only or the primary cause of autism. We cannot conclude that it has been eliminated as a possible contributor in a significant number of children. We wonder why are researchers still defending its use — why aren’t we simply removing all of it, even trace amounts, when this is clearly technically feasible? Would it make sense to inject trace amounts of lead into our babies?
The only valid conclusion based on the data presented is that autism is sadly still on the rise in California, as we’ve seen across the world. Given the continued use of thimerosal in routine childhood vaccines along with other ongoing environmental exposures to heavy metals, it is not possible to eliminate mercury as a contributing factor to this epidemic rise in autism. As we still do not know what causes the vast majority of autism cases, we should be studying all possible environmental triggers while cautiously avoiding any potential neurotoxin exposures.
We are in the midst of a public health crisis in need of urgent and immediate attention.
In the absence of a plausible explanation for a disorder that has gone from 1 in 10,000 to 1 in 150 in less than 20 years, we call on the CDC to declare autism a national emergency and for Congress to initiate oversight hearings to investigate what has happened to a generation of America’s children. This is an epidemic and we believe environmental factors are clearly implicated. There is no such thing as a genetic epidemic.
The Deirdre Imus Environmental Center for Pediatric Oncology® continues to support the need for an independent study that will investigate autism rates in vaccinated versus non-vaccinated populations and a significant investment of financial resources directed specifically towards environmental exposures and their affects on children’s health.
CRITIQUES OF THE STUDY
Thimerosal Removal Not Complete Until 2003 – The authors’ statement that “The exclusion of thimerosal from childhood vaccines in the United States was accelerated from 1999 to 2001” is inaccurate. Vaccine makers were asked to voluntarily remove thimerosal from childhood vaccines in July of 1999, a process that took a few years. Likewise, the authors claim their study is inconsistent with a thimerosal association because “the prevalence of autism in childrenreported to the DDS has increased consistently for childrenborn from 1989 through 2003, inclusive of the period when exposureto TCVs has declined.” The last TCVs (with the exception of the influenza vaccine) were manufactured in 2001, but expired in 2003.
Youngest Cohort Data is Unreliable – The study states that there were more 3-5-year olds in the first quarter of 2007 (children born from 2002-2004) than among 3-5 year olds in the first quarter of 2006 (born from 2001-2003). But diagnoses among younger children can vary, depending especially on the average age of diagnosis in any given area. This is why the CDC waits until children are 8 years of age in order to conduct its own autism surveillance studies, which are considered to be the most accurate in the United States. Unfortunately, the CDC surveillance system does not include children in California.
Falling Age of Diagnosis Creates Artificial Increase – One reason that CDC waits until children are 8 years of age is because each year, the average age of autism diagnoses goes down. The result is that, each year, more and more three-year-olds are diagnosed as compared to prior years. This is supported by a study published in the December 2008 issue of Archives of Pediatric and Adolescent Medicine.[75] “Shifts in age at diagnosis inflated the observed prevalence of autism in young children in the more recent cohorts compared with the oldest cohort,” the authors wrote. “This study supports the argument that the apparent increase in autism in recent years is at least in part attributable to decreases in the age at diagnosis over time.”
IOM: California Data Not Reliable For Incidence Studies – In its 2004 report on thimerosal and autism, the IOM Immunization Safety Committee discussed two reports from California’s DDS system (from 1999 and 2003) that showed a large increase in autism cases from 1987 to 2002. Those data were “widely cited as evidence of an increase in the incidence of ASD in the United States,” the panel wrote. But, it cautioned: “The report stresses that the study was not designed to measure trends in autism incidence, and the data should therefore be interpreted with caution. Several methodological limitations have been cited, including the failure to account for changes over time in the population size or composition, in diagnostic concepts, in case definitions, or in age of diagnosis.” (Emphasis added).
DDS: Be Careful Drawing Conclusions – On a webpage titled “Data Interpretation Considerations and Limitations,” the DDS cautions: “Although information published by DDS in the Quarterly Client Characteristics Report is often used by media and research entities to develop statistics and draw conclusions some of these findings may misrepresent the quarterly figures.” In addition, it says, “Increases in the number of persons reported from one quarter to the next do not necessarily represent persons who are new to the DDS system.”[76]
Authors: Findings Must Be Confirmed – The authors concluded that “Continuing evaluation of the trends in the prevalence of autism for children born in recent years is warranted to confirm our findings.”Unfortunately, that will never be possible in California, where entry criteria for DDS services were broadly expanded to include children with PDD-NOS and Asperger’s Disorder in January, 2008. “Information from these new items will not be comparable to prior information,” a DDS statement says.
SUMMARY – The conclusions of this study rely solely on one year of data in one state among the youngest children who presumably received markedly less thimerosal in their vaccines. Basing such a conclusion on the youngest cohort data is unreliable, partly because the falling age of diagnosis creates an artificial increase. The IOM said the California data is not reliable for incidence studies, the California Department of Developmental Services cautioned against drawing conclusions from the database, and the authors themselves warned that their findings must be confirmed from later data, something that has not happened – and cannot happen.