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Press Release: New Research Finds No Evidence That Thimerosal-Containing Vaccines Affect Behavior or Neuroanatomy in Infant Primates

30 Sep

Below is a press release from the Johnson Center for Child Health and Development (formerly Thoughtful House). The press release discusses a recent study which investigated the safety of vaccine schedules (present and past) using monkeys as test subjects.

The study is a follow on study to a previous series of pilot studies involving some of the same authors. The pilot studies were considered by many to be an indication of evidence that vaccines cause autism and other neurological conditions. This larger study shows no evidence of adverse effects from vaccines.

Here is the press release:

New Research Finds No Evidence That Thimerosal-Containing Vaccines Affect Behavior or Neuroanatomy in Infant Primates

(Austin, Texas) – September 28, 2015 – New research finds no evidence that thimerosal- containing vaccines cause negative behaviors or result in neuropathology in infant primates, according to a study that will be published today in the Proceedings of the National Academy of Sciences. In this study, conducted by Dr. Dwight German of the University of Texas Southwestern School of Medicine, and colleagues, infant rhesus macaques received several pediatric vaccines containing thimerosal (a mercury-based preservative) in a schedule similar to that given to infants in the 1990s. Other animals received just the measles-mumps- rubella (MMR) vaccine, which does not contain thimerosal, or an expanded vaccine schedule similar to that recommended for US infants today. Control animals received a saline injection.

Regardless of vaccination status, all animals developed normal social behaviors. Cellular analysis of three brain regions, the cerebellum, amygdala and hippocampus (all known to be altered in autism), was similar in vaccinated and unvaccinated animals.

“This comprehensive analysis of social behavior and neuropathology in 12-18 month old rhesus macaques indicated that vaccinated primates were not negatively affected by thimerosal; the same was true for animals receiving an expanded 2008 vaccine schedule, which is similar to that recommended for US infants today” explained Dr. Laura Hewitson of The Johnson Center for Child Health and Development, one of the principle investigators working on the study. Hewitson was part of a team of researchers from The Johnson Center; the University of Texas Southwestern; the Center on Human Development and Disability Infant Primate Research Laboratory; the Washington National Primate Research Center (WaNPRC) at the University of Washington, Seattle WA; and Texas A&M Health Science Center & Central Texas Veterans Health Care System.

According to Hewitson, the study was designed to compare the safety of different vaccination schedules, including the schedule from the 1990s, when thimerosal was used as a preservative in multi-dose vaccine preparations. The data from this study indicate that administration of TCVs and/or the MMR vaccine to rhesus macaques did not result in neuropathological abnormalities,or aberrant behaviors, like those often observed in autism.


Citation
Administration of thimerosal-containing vaccines to infant rhesus macaques does not result in autism-like behavior or neuropathology. Bharathi S. Gadad, Wenhao Li, Umar Yazdani, Stephen Grady, Trevor Johnson, Jacob Hammond, Howard Gunn, Britni Curtis, Chris English, Vernon Yutuc, Clayton Ferrier, Gene P. Sackett, C. Nathan Marti, Keith Young, Laura Hewitson and Dwight C. German. PNAS

This article can be downloaded for free here.

This study was supported by The Ted Lindsay Foundation, SafeMinds, National Autism Association, and the Johnson and Vernick families. This work was also supported by WaNPRC Core Grant RR00166 and CHDD Core Grant HD02274.

About The Johnson Center
The mission of The Johnson Center for Child Health and Development is to advance the understanding of childhood development through clinical care, research, and education.

Previous Press Releases
For Immediate Release
Contact: media@johnson-center.org
512-732-8400


By Matt Carey

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SafeMinds: why won’t you tell your membership about the vaccine safety study you funded? Perhaps because it says vaccines are safe?

28 Aug

Earlier this year a paper was published on vaccine safety: Examination of the Safety of Pediatric Vaccine Schedules in a Non-Human Primate Model: Assessments of Neurodevelopment, Learning, and Social Behavior. This was a followup study to earlier pilot studies that got a lot of attention in the “vaccines-cause-autism” groups (Delayed acquisition of neonatal reflexes in newborn primates receiving a thimerosal-containing hepatitis B vaccine: influence of gestational age and birth weight and Influence of pediatric vaccines on amygdala growth and opioid ligand binding in rhesus macaque infants: a pilot study.)

It is worth noting that the pilot studies didn’t link vaccines to autism. They did make claims that some early reflexes were delayed in the monkeys given thimerosal containing vaccines. If you see someone talking about “root” or “snout” or “suck” reflexes in a vaccine discussion, they are referring to the studies above. These were pilot studies–small preliminary studies to see if it is worth launching a larger study. As such the results should have been taken with caution. But caution is not what groups like SafeMinds (or any of the groups that promote the failed vaccine-autism link) are known for. Inflating any scrap of evidence that can support their political point of view, that’s what they are known for.

SafeMinds made a big deal out of the early studies. Mark Blaxill (then of SafeMinds) called the study a “blockbuster” in a four thousand word analysis. That’s a lot of space to devote considering the full study was eight thousand words. And, as noted already, preliminary. But politics is politics.

Now, an intellectually honest person, or group, would watch for the followup study and report on it no matter the result. Because, let’s face it, if you are going to spend 4000 words overstating the importance of a study, scaring people and instilling them with guilt and pain over their child’s disability, you have a responsibility to do a follow up.

If you are intellectually honest.

So, as noted above, the follow up study was published. It was published in April. Four months ago. And I don’t see anything from Mr. Blaxill on the Age of Autism blog (where he posted his “blockbuster” article) or at the SafeMinds website on the followup study. SafeMinds has their own blog, and if you search it for, say “snout”, you get this article (Ground-Breaking Monkey Study: Mercury-Containing Hepatitis B Vaccine Causes Brain Damage) on the pilot study, calling it “groundbreaking” and claiming that it demonstrates that the thimerosal containing HepB vaccine causes brain damage.

Very strong words. Words which, if overblown, are very damaging. Imagine going through life as a parent thinking that you agreed to a vaccine and that caused brain damage to your child. Now imagine that the evidence you used to draw that conclusion was (a) not strong to begin with and (b) now refuted.

Wouldn’t you want to know the truth? Wouldn’t you expect the people and the organizations that convinced you of this falshood to seek you out and correct their mistake?

And this is why people don’t hold Mr. Blaxill or SafeMinds in high regard. They are quick to scare but don’t have the courage to admit they were wrong. Courage isn’t standing up and saying unpopular truths. Courage is standing up and admitting that your “unpopular truth” was, in fact, not the truth at all.

Now, why pick on SafeMinds in specific here? A lot of people and groups jumped on the pilot study and spread a lot of fear. Check out the footnotes of the study.

This work was supported by the Ted Lindsay Foundation, SafeMinds, National Autism Association, the Vernick family, and the Johnson family

SafeMinds helped fund the new study. The one they are ignoring. They were likely aware of the results before they were published. But no word.

I expect more from decent advocacy organizations. But I am not surprised with SafeMinds, nor Mark Blaxill.

Yes, the National Autism Association did too and they need to step up as well (a point I hope to make in a later article).

How about the Johnson Family? Well, the Johnson Center stepped up and put out a press release New Research Finds No Evidence That Thimerosal-Containing Vaccines Affect Neurodevelopment and Behavior in Infant Primates. (all SafeMinds, the Age of Autism and the National Autism Association needs to do as a start is publish the press release).

Here’s the last sentence of the press release, quoting the lead researcher: “Despite these limitations, the data in this primate study overwhelmingly provides support for the safety of pediatric vaccines”

It would take a lot of courage for SafeMinds and Mark Blaxill to publicize such a statement. More than they have.


By Matt Carey

Press Release: New Research Finds No Evidence That Thimerosal-Containing Vaccines Affect Neurodevelopment and Behavior in Infant Primates

26 Apr

Below is a press release from the Johnson Center (formerly Thoughtful House). It is about a recent follow-up study they performed (discussed here). I’ll give the press release below with no further comment except to highlight this statement by the lead researcher: “Despite these limitations, the data in this primate study overwhelmingly provides support for the safety of pediatric vaccines.

New Research Finds No Evidence That Thimerosal-Containing Vaccines Affect Neurodevelopment and Behavior in Infant Primates

(Austin, Texas) – February 18, 2015 – A research study published today in Environmental Health Perspectivesreported that vaccination of infant macaques with thimerosal-containing vaccines did not negatively impact neurodevelopment, cognition, or behavior. In this study animals received several pediatric vaccines containing thimerosal (a mercury-based preservative) in a schedule similar to that given to infants in the 1990s. Other animals received just the measles-mumps-rubella (MMR) vaccine, which does not contain thimerosal, or an expanded vaccine schedule similar to that recommended for US infants today. Control animals received a saline injection. Regardless of vaccination status, all animals developed normally.

“This comprehensive study of infant primate development, including analyses of learning, cognition, and social development, indicated that vaccinated primates were not negatively affected by thimerosal or the MMR vaccine; the same was true for animals receiving an expanded vaccine schedule” explained Dr. Laura Hewitson of The Johnson Center for Child Health and Development, the principle investigator of the study.

Hewitson worked with a team of researchers at the Center on Human Development and Disability Infant Primate Research Laboratory and the Washington National Primate Research Center (WaNPRC) at the University of Washington, Seattle WA. According to Hewitson, the study was designed to compare the safety of different vaccination schedules, including the schedule from the 1990s, when thimerosal was still used as a preservative in multi-dose vaccine preparations. Although in 1999 the FDA and the American Academy of Pediatrics recommended that thimerosal be removed from vaccines in the US, it is still used as a preservative in multi-dose flu shots, which are recommended for pregnant women and children 6 months of age and older.

“This is the first time the safety of the entire pediatric vaccine schedule has been investigated in a relevant animal model,” said Dr. Judy Van de Water from the UC-Davis MIND Institute, who was not involved in this study.

Hewitson also noted, “As with any animal study, assessments were implemented under controlled laboratory conditions. We did not test all of the interacting variables that could contribute to an adverse outcome, such as birth weight, gestational age, genetic vulnerability, or in utero and post-natal chemical exposures. The interaction between multiple environmental exposures or genetic factors that may impact vaccine response, which is an important aspect of the vaccine debate, was not addressed in this study. Despite these limitations, the data in this primate study overwhelmingly provides support for the safety of pediatric vaccines.”

Citation

Examination of the Safety of Pediatric Vaccine Schedules in a Non-Human Primate Model: Assessments of Neurodevelopment, Learning, and Social Behavior. Britni Curtis, Noelle Liberato, Megan Rulien, Kelly Morrisroe, Caroline Kenney, Vernon Yutuc, Clayton Ferrier, C. Nathan Marti, Dorothy Mandell, Thomas M. Burbacher, Gene P. Sackett and Laura Hewitson. Environmental Health Perspectives, Feb 18, 2015; doi:10.1289/ehp.1408257.
Once the embargo lifts, this article can be downloaded for free at http://ehp.niehs.nih.gov/1408257.

This study was supported by The Ted Lindsay Foundation, SafeMinds, National Autism Association, the Vernick family, and the Johnson family. This work was also supported by WaNPRC Core Grant RR00166 and CHDD Core Grant HD02274.

About The Johnson Center

The mission of The Johnson Center for Child Health and Development is to advance the understanding of childhood development through clinical care, research, and education.


By Matt Carey

Comment on: Examination of the Safety of Pediatric Vaccine Schedules in a Non-Human Primate Model: Assessments of Neurodevelopment, Learning, and Social Behavior.

21 Feb

There is a common myth one hears from one group of autism parents: there is no research on autism and vaccines being performed. Usually this is combined with the insinuation that the government is scared of vaccine/autism research. The claims are often made by people who should (and likely do) know better.

One of the few places one can find a discussion of the ongoing vaccine/autism work is here at Left Brain/Right Brain. In a post last year I address the question of Why won’t the government fund vaccine/autism research?, which was really a post about how there is work being funded. In case the title was unclear, I also wrote More of that vaccine/autism research that doesn’t exist. Other articles include What projects are being funded in autism research? Part 1: vaccines and GI issues.

In one of those articles I wrote:

There’s a study by Gene Sackett’s group, A PRIMATE MODEL OF GUT, IMMUNE, AND CNS RESPONSE TO CHILDHOOD VACCINES. This appears to be a follow on project to the Laura Hewitson studies that were discussed a great deal online a few years ago.

And, guess what? A study by Gene Sackett, together with Laura Hewitson and others, has just been published: Examination of the Safety of Pediatric Vaccine Schedules in a Non-Human Primate Model: Assessments of Neurodevelopment, Learning, and Social Behavior. It may not be the study referenced above as that study was government funded, but this new study addresses some of the concerns raised by previous studies published by Laura Hewitson’s team. If you wonder what I mean by “addressed”, here’s the last phrase of the abstract: the study “…provided no consistent evidence of neurodevelopmental deficits or aberrant behavior in vaccinated animals.”

No evidence of harm.

Gene Sackett was a collaborator on one of those previous studies by Laura Hewitson: Delayed acquisition of neonatal reflexes in newborn primates receiving a thimerosal-containing hepatitis B vaccine: influence of gestational age and birth weight. This study was discussed a great deal by those promoting the vaccine/autism link (say here, here, here and elsewhere. It was called a “blockbuster” study by Mark Blaxill (then of SafeMinds, now of the Canary Party, both groups who promote the failed idea that the rise in autism diagnoses was caused by thimerosal in vaccines) on the Age of Autism blog. Dan Olmsted (of the same blog) called the results “explosive”. They both downplayed the preliminary nature of the study and the small sample size and way overplayed the importance of the results.

And as this new study clarifies, both were wrong. Both spread guilt and fear: one can still find parents talking online about how their child was delayed in one of the reflexes discussed in the study and, thus, was harmed by thimerosal in vaccines. Just an example of the harm the people pushing the idea that vaccines and autism are linked have caused.

As noted above, this new study clears up the concerns raised by the earlier studies. If history is any guide, Mr. Olmsted and Mr. Blaxill will not demonstrate the courage needed to admit their mistakes nor try to correct the damage they have caused. I would love to be wrong and have to write an apology to them.

Here is the abstract to Examination of the Safety of Pediatric Vaccine Schedules in a Non-Human Primate Model: Assessments of Neurodevelopment, Learning, and Social Behavior.

Abstract
BACKGROUND:
In the 1990s, the mercury-based preservative, thimerosal, was used in most pediatric vaccines. While there are currently only two thimerosal-containing vaccines (TCVs) recommended for pediatric use, parental perceptions that vaccines pose safety concerns are affecting vaccination rates, particularly in light of the much expanded and more complex schedule in place today.
OBJECTIVES:
The objective of this study was to examine the safety of pediatric vaccine schedules in a non-human primate model.
METHODS:
We administered vaccines to 6 groups of infant male rhesus macaques (n=12-16/group) using a standardized thimerosal dose where appropriate. Study groups included the recommended 1990s pediatric vaccine schedule, an accelerated 1990s primate schedule with or without the measles-mumps-rubella (MMR) vaccine, the MMR vaccine only, and the expanded 2008 schedule. We administered saline injections to age-matched control animals (n=16). Infant development was assessed from birth-12 months of age by examining the acquisition of neonatal reflexes, the development of object concept permanence (OCP), computerized tests of discrimination learning, and infant social behavior. Data were analyzed using ANOVAs, multi-level modeling, and survival analyses, where appropriate.
RESULTS:
There were no group differences in the acquisition of OCP. During discrimination learning animals receiving TCVs had improved performance on reversal testing, although some of these same animals performed poorer in subsequent learning set testing. Analysis of social and non-social behaviors identified few instances of negative behaviors across the entire infancy period. While some group differences in specific behaviors were reported at 2 months of age, by 12 months all infants, irrespective of vaccination status, had developed the typical repertoire of macaque behaviors.
CONCLUSIONS:
This comprehensive five-year, case-control study, which closely examined the effects of pediatric vaccines on early primate development, provided no consistent evidence of neurodevelopmental deficits or aberrant behavior in vaccinated animals.

Let’s repeat that conclusion for emphasis: This comprehensive five-year, case-control study, which closely examined the effects of pediatric vaccines on early primate development, provided no consistent evidence of neurodevelopmental deficits or aberrant behavior in vaccinated animals.

The full paper is available online. In it you can read this:

This data is in contrast to our previous pilot study in which a delay in the acquisition of the root, suck, and snout survival reflexes were reported for primate infants following exposure to the birth dose of the thimerosal containing Hep B vaccine (Hewitson et al. 2010a). This discrepancy is most likely due to the larger number of animals in the present study providing more accurate estimates. Furthermore, in the present study reflexes were examined from birth to 21 days of age, during which some animals received multiple TCVs (not just a single Hep B vaccine as was used in the previous 23 study), and yet no detrimental effects on the acquisition of survival reflexes were reported for these animals.

Hewitson 2010a is Delayed acquisition of neonatal reflexes in newborn primates receiving a thimerosal-containing hepatitis B vaccine: Influence of gestational age and birth weight. This is the “blockbuster” study according to Mark Blaxill. Ironically, Mr. Blaxill’s article links to the first publication of the “blockbuster”, the version that was retracted.

The first thing that people who promote the vaccine/autism link would do with a study like this, one that doesn’t find a link between vaccines and harm, is claim that it isn’t “independent” and the authors and/or funding agencies are too biased. So, let’s look at the authors

Britni Curtis,1 Noelle Liberato,1 Megan Rulien,1 Kelly Morrisroe,1 Caroline Kenney,1 Vernon Yutuc,1 Clayton Ferrier,1 C. Nathan Marti,2 Dorothy Mandell,3 Thomas M. Burbacher,1,4 Gene P. Sackett,1,5 and Laura Hewitson1,6,7

1Infant Primate Research Laboratory (IPRL), Washington National Primate Research Center, and Center on Human Development and Disability (CHDD), Seattle, Washington, USA; 2Abacist Analytics, LLC, Austin, Texas, USA; 3Independent Consultant, Austin, Texas, USA; 4Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA; 5Department of Psychology, University of Washington, Seattle, Washington, USA; 6The Johnson Center for Child Health and Development, Austin, Texas, USA; 7Department of Psychiatry, University of Texas Southwestern, Dallas, Texas, USA

Laura Hewitson was the lead researcher in the previous macaque studies, the ones often quoted as providing evidence of a link between thimerosal and autism. Her organization (The Johnson Center for Child Health and Development) was formerly referred to as Thoughtful House and was directed in that time by Andrew Wakefield. Thomas Burbacher and Gene Sackett have also been involved with previous animal studies on thimerosal, including this one often cited again as evidence of a link between vaccines and autism.

The funding?

This work was supported by The Ted Lindsay Foundation, SafeMinds, National Autism Association, the Vernick family, and the Johnson family. This work was also supported by WaNPRC Core Grant RR0166 and CHDD Core Grant HD02274.

Both SafeMinds and the National Autism Association are strong proponents of the idea that vaccines cause autism.

Under competing financial interests we read:

Competing financial interests: Drs. Marti and Mandell provided consulting services as independent contractors in regards to the data analyses. Neither person has provided services to pharmaceutical companies that manufacture vaccines or their representatives, nor have they been an expert witness in thimerosal, or similar suits. The other authors declare they have no actual or potential competing financial interests.

I will leave you with the final paragraph of the new study

In summary, we did not find evidence of an adverse impact of vaccination status on early neurodevelopmental measures, including the acquisition of neonatal reflexes and the development of object permanence. This was true for animals receiving TCVs, as well as animals in the 2008 group, which received the expanded pediatric vaccine schedule that remains very similar to the currently recommended schedule. Although some animals receiving TCVs performed better in the reversal phase of discrimination learning compared to controls, this association was not consistent across all study groups with thimerosal exposure. Furthermore, learning set performance appeared to be poorest for animals in the TCV group but this observation was not mirrored in the 1990s Primate group. Finally, all infants, irrespective of vaccine status, developed the typical social behaviors for this age of animal, with very few instances of negative behaviors reported. While the data as a whole does not support a consistent adverse effect of TCVs on primate development, factors that may modulate the toxicokinetics and toxicodynamics of thimerosal, such as genetics, gender, birth weight, gestational age, maternal health, and chemical co-exposures, should be thoroughly investigated.


By Matt Carey

Laura Hewitson has left the University of Pittsburgh

26 Jul

Laura Hewitson is the lead researcher on a series of studies on comparing vaccinated and unvaccinated macaque monkeys. This work became public first in the 2008 IMFAR conference. At that time and since, the work from these studies has been strongly criticized. Dr. David Gorski of Science Based Medicine discussed those abstracts. It is very likely that the new conflict of interest declaration policy for IMFAR resulted from Ms. Hewitson’s lack of declaration of her own COI at IMFAR (she has filed a claim with the vaccine court on behalf of her child). One paper resulting from that study was withdrawn before it was published (discussed by Countering Age of Autism and Respectful Insolence). More recently, a study from this series was published in which conclusions were drawn based on only 2 control animals. Those control animals underwent brain shrinkage during a critical period of infant growth. In other words, there was something seriously wrong with the control animals and, hence, the entire study. The study (and subsequent discussions by groups such as SafeMinds) spun the brain shrinkage around to claim that the “The vaccinated primates also showed altered maturation of their brains’s [sic] amygdalas.”

Ms. Hewitson has listed here professional affiliations as:

1Department of Obstetrics and Gynecology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA;
2Thoughtful House Center for Children, Austin, TX, USA;

In 2008 she was listed as Associate Professor of Obstetrics, Gynecology & Reproductive Sciences on the University of Pittsburgh’s website. That is the last date for an internet archive version of that page. A google cache version of the page from June 2010 listed her as “adjunct” Associate Professor. Adjunct faculty are typically part time or people from other institutions who are working in some capacity with the University.

Ms. Hewitson’s webpage link at Pitt is no longer active. She is no longer listed on the faculty page for the Pittsburgh Development Center (PDC). The PDC confirmed that she is no longer on the faculty there.

Before people start speculating, the most likely explanation is that it simply became too difficult to balance a career at Thoughtful House in Texas with a faculty appointment in Pennsylvania.

This will mean that in the future Ms. Hewitson will be unable to use her University of Pittsburgh affiliation to bolster the credibility of her research. Studies begun while at Pitt will likely continue to show that affiliation (such as the recently published study on the amygdalas of macaques).

Whatever the reason for her departure, I welcome it. I don’t believe that a fine institution like Pitt should have its name attached to the level of research in the recent paper. It is difficult to simply put into simply how poor the quality of that study was.

The genie is out of the bottle. Part II – more genies, more bottles

16 Jul

Was it any surprise that the journal that published the recent Hewitson stinker did so? Not really. Straight from the opening lines of the Editorial the direction this journals ‘science’ would take was clear:

This issue of Acta Neurobiologiae Experimentalis is fully devoted to the issues of autism. The idea for this topic came from Professor Dorota Majewska…

Did it indeed? I wonder if this is the same Professor Dorota Majewska who has signed her name at We Support Andy Wakefield? I’m not sure how common this name is but it would be a monumental coincedence if they weren’t one and the same person.

Getting back to the Editorial, we see some familar names from the outliers of scientific credibility – Hitlan, DeSoto, Geier – that give pause to the peer review process this journal makes its papers undertake. Are they aware of how little regard these names and their associated ‘science’ is held in in more prestigious journals and law courts?

The Editor discusses the Hewitson paper thusly:

An alarming finding is reported by Hewitson and coworkers (Ref. 4), showing that, in infant monkeys that were immunized, the amygdala does not show the normal pattern of maturation but is hypertrophied. Although these are only preliminary data, given the well-known role of the amygdala in generation of fear and other negative emotions, they support the possibility that there is a link between early immunization and the etiology of autism

How is it that an Editor and his peer review team missed that which LB/RB’s own Sullivan caught immediately? That according to this ‘alarming’ paper, pieces of the control subjects brains apparently shrank during the course of the experiment. That would certainly be an alarming result – if it were in any way true. How could it be accounted for? Too few animals in the control group or maybe just bad maths. Either way, to describe this paper as alarming might be accurate – but not necessarily for the reason that the Editor obviously feels.

They also seemed to miss Sullivan’s other finding – that two of the subjects just disappeared from the paper. To quote Sullivan:

Weren’t there 4 monkeys in the control group and 12 monkeys in the vaccinated group? What happened to the other 2 of the control subjects?

Shoddy.

From IMFAR to Poland: how a monkey study can totally change

16 Jul

I just blogged about a new paper “proving” once again that vaccines cause autism. This is a paper from Mr. Wakefield’s team. Thanks to a link provided by KWombles of the Countering Age of Autism blog, we can compare the current paper to what the authors claimed two years ago.

Here is the new paper (published in a journal from Poland):
Influence of pediatric vaccines on amygdala growth and opioid ligand binding in rhesus macaque infants: A pilot study

by Hewitson L. Lopresti B, Stott C, Mason N.S., Tomko.

Here is the abstract from IMFAR in 2008:

Pediatric Vaccines Influence Primate Behavior, and Amygdala Growth and Opioid Ligand Binding

L. Hewitson , Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA
B. Lopresti , Radiology, University of Pittsburgh, Pittsburgh, PA
C. Stott , Thoughtful House Center for Children, Austin, TX
J. Tomko , Pittsburgh Development Center, University of Pittsburgh, Pittsburgh, PA
L. Houser , Pittsburgh Development Center, University of Pittsburgh, Pittsburgh, PA
E. Klein , Division of Laboratory Animal Resources, University of Pittsburgh, Pittsburgh, PA
C. Castro , Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA
G. Sackett , Psychology, Washington National Primate Research Center, Seattle, WA
S. Gupta , Medicine, Pathology & Laboratory Medicine, University of California – Irvine, Irvine, CA
D. Atwood , Chemistry, University of Kentucky, Lexington, KY
L. Blue , Chemistry, University of Kentucky, Lexington, KY
E. R. White , Chemistry, University of Kentucky, Lexington, KY
A. Wakefield , Thoughtful House Center for Children, Austin, TX

Background: Macaques are commonly used in pre-clinical vaccine safety testing, but the combined childhood vaccine regimen, rather than individual vaccines, has not been studied. Childhood vaccines are a possible causal factor in autism, and abnormal behaviors and anomalous amygdala growth are potentially inter-related features of this condition.

Objectives: The objective of this study was to compare early infant cognition and behavior with amygdala size and opioid binding in rhesus macaques receiving the recommended childhood vaccines (1994-1999), the majority of which contained the bactericidal preservative ethylmercurithiosalicylic acid (thimerosal).

Methods: Macaques were administered the recommended infant vaccines, adjusted for age and thimerosal dose (exposed; N=13), or saline (unexposed; N=3). Primate development, cognition and social behavior were assessed for both vaccinated and unvaccinated infants using standardized tests developed at the Washington National Primate Research Center. Amygdala growth and binding were measured serially by MRI and by the binding of the non-selective opioid antagonist [11C]diprenorphine, measured by PET, respectively, before (T1) and after (T2) the administration of the measles-mumps-rubella vaccine (MMR).

Results: Compared with unexposed animals, significant neurodevelopmental deficits were evident for exposed animals in survival reflexes, tests of color discrimination and reversal, and learning sets. Differences in behaviors were observed between exposed and unexposed animals and within the exposed group before and after MMR vaccination. Compared with unexposed animals, exposed animals showed attenuation of amygdala growth and differences in the amygdala binding of [11C]diprenorphine. Interaction models identified significant associations between specific aberrant social and non-social behaviors, isotope binding, and vaccine exposure.

Conclusions: This animal model, which examines for the first time, behavioral, functional, and neuromorphometric consequences of the childhood vaccine regimen, mimics certain neurological abnormalities of autism. The findings raise important safety issues while providing a potential model for examining aspects of causation and disease pathogenesis in acquired disorders of behavior and development.

Emphasis added by me.

Why? First, to point out the change in the author list. Of 13 authors on the original abstract, only 4 remain. One can speculate as to why the others were dropped (or pulled their names) from the author list.

A new author was added, N.S. Mason.

How about other changes? Well, 2 years ago they had data on 13 vaccinated monkeys. Now it is only 9. Two years ago they had data on 3 controls. Now it is only 2.

What happened?

OK, while you are working that one out, here’s the big one. Two years ago the vaccinated monkeys “showed attenuation of amygdala growth”

Now, the amygdalas are larger in the vaccinated monkeys. What? Yep. Before they had “attenuated growth” and now they are growing faster than the unvaccinated animals?