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.
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.
The objective of this study was to examine the safety of pediatric vaccine schedules in a non-human primate model.
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.
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.
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.
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