CDC Director Dr. Julie Gerberding has delivered a potentially explosive report to the powerful House Appropriations Committee, in which she admits to a startling string of errors in the design and methods used in the CDC's landmark 2003 study that found no link between mercury in vaccines and autism, ADHD, speech delay or tics.
Gerberding was responding to a 2006 report from the National Institute of Environmental Health Sciences (NIEHS), which concluded that methodology such as that used in the CDC's flagship thimerosal safety study is riddled with "several areas of weaknesses" that combine to "reduce the usefulness" of using the data in such a way.
"CDC concurs," Dr. Gerberding wrote in an undated report to Congress, (provided to me through a Capital Hill staffer) adding that her agency "does not plan to use" the database in question, the Vaccine Safety Datalink, (VSD) for any future "ecological studies" of autism (though that is exactly what they did in the 2003 study).
In fact, Gerberding's report said, use of the VSD for an ecological study now, comparing autism rates before and after the removal of most mercury from vaccines, "would be uninformative and potentially misleading."
Ecological vaccine studies are large, epidemiological analyses of risks and trends using computerized data from large populations -- in this case children enrolled at several big HMOs -- without linking results to actual individual outcomes.
CDC officials conducted at least five separate analyses of the data over a four-year period from 1999-2003. The first analysis showed that children exposed to the most thimerosal by one month of age had extremely high relative risks for a number of outcomes, compared with children who got little or no mercury: The relative risk for ADHD was 8.29 times higher; for autism, it was 7.62 times higher; ADD, 6.38 times higher; tics, 5.65 times; and speech and language delays were 2.09 more likely among kids who got the most mercury.
Over time, however, all of these risks declined into statistical insignificance, statistical inconsistency or else outright oblivion: The relative risk for autism plummeted from 7.62 in the first analysis, to 2.48 in the second version, to 1.69 in the third round, to 1.52 in the fourth, and down to nothing at all in the fifth, final, and published analysis printed in the Journal Pediatrics in November of 2003.
Vaccine officials attributed the steady drop to the elimination of "statistical noise" from the data through due diligence and the endeavor for excellence in governmental statistical analysis.
Indeed, the VSD study was the main pillar of a hugely influential 2004 report by the Institute of Medicine, which also concluded that there was no evidence of link between mercury, vaccines and autism.
To this day, public health officials routinely point to five "large epidemiological studies" representing the "highest quality science," none of which found any link to thimerosal.
In fact, the American VSD study has long been held up as the best and brightest of them all (the others were in Sweden, the UK, and two in Denmark). And this reputation has stuck in the minds of medicine and the media.
Curiously though, even the study's lead author -- Dr. Thomas Verstraeten, an employee of vaccine maker GlaxoSmithKline -- protested that the VSD study "found no evidence against an association, as a negative study would. In fact, he said that additional study was needed, which "is the conclusion to which a neutral study must come."
That's when Congress stepped in.
In 2005, a group of Senators and Representatives headed by Sen. Joe Lieberman wrote to the NIEHS (an agency of the National Institutes of Health) saying that many parents no longer trusted the CDC to conduct independent minded studies of its own vaccine program. Lieberman et al asked NIEHS to review the CDC's work on the vaccine database and report back with critiques and suggestions.
Among the official tasks given to the NIEHS panel were to "Identify the strengths and weaknesses of the VSD for evaluating the possible association between exposures to thimerosal-containing vaccines and AD/ASD." Another was to "Advise NIEHS and CDC on the feasibility of a new VSD study to compare autism rates before and after removal of thimerosal from most US childhood vaccines, using an ecologic study (an epidemiologic design where there is no linkage between individual-level data on exposure and health outcome).
The final NIEHS report was a serious and thoughtful critique of if an how the CDC improve on the design, conduct and analysis of VSD data in the future. Still, the NIEHS panel "identified several serious problems," with using VSD data for ecological studies -- including the 2003 study - something to which the agency had not responded -- until now.
In her letter to the House Appropriations Committee, the CDC Director responded directly to many -- though not all -- of the most important critiques and recommendations contained in the NIEHS panel report.
For example, the NIEHS had said the VSD data failed to account for other mercury exposures, including maternal sources from flu shots and immune globulin, as well as mercury in food and the environment.
"CDC acknowledges this concern and recognizes this limitation," the Gerberding reply says. This limitation would have applied to the 2003 Verstraeten study, as well as any future ecological analyses.
The NIEHS also questioned why CDC investigators eliminated 25% of the study population for a variety of reasons, even though this represented, "a susceptible population whose removal from the analysis might unintentionally reduce the ability to detect an effect of thimerosal." This strict entry criteria would likely lead to an "under-ascertainment" of autism cases, the NIEHS reported. Again, this would have been an issue in the Verstraeten data as well.
"CDC concurs," Gerberding wrote, again noting that its study design was "not appropriate for studying this vaccine safety topic. The data are intended for administrative purposes and may not be predictive of the outcomes studied."
Another serious problem is that the HMOs have changed the way they tracked and recorded autism diagnoses over time, including during the period when vaccine mercury levels were in decline. Such changes could "affect the observed rate of autism and could confound or distort trends in autism rates," the NIEHS warned.
"CDC concurs," Dr. Gerberding wrote again, "that conducting an ecologic analysis using VSD administrative data to address potential associations between thimerosal exposure and risk of ASD is not useful."
Read that sentence one more time. The head of the CDC is saying that its most powerful and convincing piece of exonerating evidence for thimerosal was based on anecological analysis of data whose methodology would be, in effect, "useless" for future study.
I hope everyone will read these documents, including the recommendations to make the VSD better, and the CDC's agreement with all of the suggestions. Hopefully, this data can still be used in some effective way.
As questionable as the US thimerosal methodology was, "it was an improvement on other studies, including the two in Denmark, both of which had serious weaknesses in their designs," Dr. Irva Hertz-Picciotto, Professor of Public Health at UC Davis Medical School and Chair of the NIEHS panel, told reporter Dan Olmsted at UPI.
That leaves very little for the CDC to go on in terms of proving that thimerosal and autism are not associated in any way.
Yes, there is always the study of disability services data from California -- which seem to be rising among the youngest cohorts of kids, who presumably received little or no mercury because thimerosal was largely removed from childhood shots.
But California is an "ecological study" with problems of its own.
"Although (this) information is often used by media and research entities to develop statistics and draw conclusions, some of these findings may misrepresent the quarterly figures," cautions the website of the California Department of Developmental Services (DDS). "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."
Even the CDC admits that "there are several limitations" with linking a VSD study design with the California data, Gerberding wrote to Congress, because, among other things, California only counts "persons who were referred to and/or voluntarily entered" the disability system."
It will be interesting to see how the House Committee -- and the mainstream media -- react to this rather breathtaking confession by the CDC, which does seem to want to conduct the best vaccine-autism science possible (see Gerberding's replies to NIEHS recommendations for improving the VSD: CDC officials are currently conducting in- depth follow up studies with VSD patients).
As the waning months of the Bush administration get underway, I can't help but wonder if a little housecleaning might be going on at some of our top health agencies.
(And on that note, please see my blog about the upcoming HHS/FDA/CDC/NIH workshop on autism triggers in mitochondrial disorders (ie, Hannah Poling and her five vaccines).
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No offense Simon.
http://epi
"This is a personal blog, reflecting the opinions of Epi Wonk. Statements on this blog do not represent the opinions of anyone other than the author. They do not represent the opinions or position of the author’s former universiti
*I have to admit it: the idea for and content of this disclaimer was stolen from Orac."
That's what I like to see -- an open mind. Because the guy mostly agrees with CDC on vaccines, you refuse to read his learned interpreta
* You and your 'vaccine defenders' on the one hand say the 'increase' in ASD is simply due to better diagnosing
Personally
* For the CDC/p.h. authoritie
I predict that they will now cling to their " thimerosal has been removed" mantra in an attempt to once again distract and mislead. However those of us who have followed this controvers
We know the CDC is quickly losing all credibilit
Never under estimate the skill evil exercises in deceiving humanity.
Wake up!
a. Because thimerosal has not "been gone" from scheduled childhood vaccines since 2002, check the CDC webstie to verify that. Those stores of thimerosal laden shots (which you can find in doctor's offices across the country) are just now reaching their expiration dates. I believe it was Dr. Jay Gordon who said if you take the "trace amount" of thimerosal we find in today's childhood vaccines and put it in a glass of water, you render that glass of water toxic. Thimerosal is a neurotoxin
and,
b. Because it's not just the thimerosal
Not relevant? Excuse me. My son was born in 1992 when the full amount of mercury was in the shots!
The fact that they are now *phasing out* mercury is great for the children rec'ing the shots today, but that will *NEVER* alter the fact that my son rec'd a boatload of mercury and was injured as a result.
You bet your ass it's relevant!!
Kelli Ann Davis
Wow. Read that sentence again. This is logic turned on its head. So far there has been no link shown between autism and mercury . Many studies indicate a lack of linkage. If there are flaws in these studies, these can (and will be) addressed in future studies. The CDC and other medical research groups aren't evil or trying to cover up anything.
If there is a link, it needs to be demonstrat
Also, if you are only saying genetics is the sole cause of autism, you have been living in a cave these past 5 years or a small cubicle within CDC.
Teresa
I refuse anything with mercury in it.
I used thimerosal contact fluid at first, but I became allergic to it. So did lots of people.
Mercury=ba
We have known this for hundreds of years.
Multiple vaccines seem like a bad idea too. The difference between a vaccine reaction and getting sick can be small. That is you get just sick enough with vaccine to build up the anti bodies. Well if you take several at once, you either give up the strong reaction per vaccine and the the effectiven
Some hypothesiz
Mercury is a ubiquitous pollutant ( he criticizes the CDC above for not including the environmen
Mercury=ba
So vaccines reactions are additive. You have evidence of this or you just pulled it out of your a...Oh, don't know if your species have such a thing. You have evidence of antigens "overwhelm
More hints. This solar system or another?
As to Mercury, Yes, it's a black and white issue. If you don't believe me, go drink some mercury and get back to me. (please don't drink mercury!)
http://www
"The number of antigens a baby is exposed to via vaccines has decreased during the past century, despite the increase in the actual number of vaccines being used. In 1960, babies routinely received five vaccines containing more than 3,000 types of antigen; now they receive about 11 vaccines with up to 126 antigens. By Offit's calculatio
That's from the study of multiple vaccines?
If concludes that infants can take 10000 vaccines at once. But that is not at all what the "theoretic
I blithely claims that you can take them all at once, due to the number of T-cells created per day.
No Epidemiolo
Maurine Meleck
in fact its been known for many years that there is a link between autism and vacines as well as untold deaths resulting from not only so called medical vacines but from experiment
anyone caring to know can find the truth.
most dont.
I hope research will continue to focus on the many variables that may contribute to the autism spectrum disorder.
What is explosive is she is FINALLY verbalizin
Houseclean
So while it is probably true that some houseclean
This seems more like a backdoor approach to still getting their (CDC) way...no one gets thae VSD data. ANd making Congress believe this is perfect. They won't order the CDC to allow anyone to use it. Everyone is no concurring it is no good?????
Help, this makes no sense to me:(
Thanks to David Kirby and many dedicated parents this issue WILL be resolved.