* CDC admits: Its Own Vaccine Study Design Uninformative and Potentially Misleading - thimerosal

[Guest guest]

The new development described herein is very important. FOIA records

obtain from CDC in 2001 appx documented their original findings of

associations between thimerosal injections during vaccinations and ADHD,

autism, sleep disorders, etc. The FOIA documents also revealed the

deliberate diluting of data - by the CDC group whose diluted findings

were published in the formerly respected journal " Pediatrics " , as

Verstraeten et al 2003. Finally, the background facts are coming forth.

- - - -

CDC: Vaccine Study Design " Uninformative and Potentially Misleading "

Kirby

June 20, 2008

http://www.huffingtonpost.com/david-kirby/cdc-vaccine-study-design_b_108398.html

CDC Director Dr. Gerberding has delivered a potentially explosive

report

<http://evidenceofharm.com/VaccineDataLinkReporttoCongressFinal.pdf>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

<http://www.niehs.nih.gov/health/topics/conditions/autism/docs/thimerosalexposur\

einpediatricvaccines102606.pdf>

from the National Institute of Environmental Health Sciences (NIEHS),

which concluded that the CDC's flagship thimerosal safety study was

riddled with " several areas of weaknesses " that combined to " reduce the

usefulness " of the study.

" CDC concurs, " Dr. Gerberding wrote in an undated mea culpa 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.

In fact, Gerberding's report said, any continued use of the VSD for

similar ecological studies of vaccines and autism " 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 ever examining a

single patient in person.

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.

Verstraeten, an employee of vaccine maker GlaxoKline -- 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.

The final NIEHS report was a serious and thoughtful critique of where

the CDC went wrong in its design, conduct and analysis of the study. The

NIEHS panel " identified several serious problems, " with the CDC's

effort, criticism 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

criticisms and recommendations contained in the NIEHS panel report.

For example, the NIEHS had criticized CDC for failing 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.

The NIEHS also took CDC to task for eliminating 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 likely led to an " under-ascertainment " of

autism cases, the NIEHS reported.

" 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 was that the HMOs 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 is, in effect, " useless. "

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.

As questionable as the US thimerosal study 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 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.

//.