Posted: Jun 06, 2013 8:14 am
As an example of the disingenuous nature of the anti-vax woo campaigners, they loudly proclaimed that vaccines "caused" autistic spectrum conditions, despite a raft of peer reviewed papers pointing to an entirely different biological basis. In particular, they claimed that thimerosal, used as a preservative in vaccines, was somehow "causing" these conditions.
Just one problem. If their hypothesis had been correct, then the moment thimerosal was removed from vaccines, we should have seen a decrease in childhood autistic spectrum diagnoses, starting from the date when thimerosal was removed. Denmark banned thimerosal in vaccines some years ago, yet childhood autistic spectrum diagnoses have continued to rise despite this, destroying any assertions that there exists a causal link between the two. Yet the anti-vaxers still continue peddling their lethal pseudoscience and duplicitous apologetics.
EDIT: A relevant peer reviewed paper is this one, comparing the outcomes in children who received a vaccine containing thimerosal, and a vaccine in which thimerosal was absent.
Full paper downloadable from here.
From that paper, we learn:
If the anti-vaxers' assertions bore any connection to reality, the figures should have been wildly divergent from this.
Just one problem. If their hypothesis had been correct, then the moment thimerosal was removed from vaccines, we should have seen a decrease in childhood autistic spectrum diagnoses, starting from the date when thimerosal was removed. Denmark banned thimerosal in vaccines some years ago, yet childhood autistic spectrum diagnoses have continued to rise despite this, destroying any assertions that there exists a causal link between the two. Yet the anti-vaxers still continue peddling their lethal pseudoscience and duplicitous apologetics.
EDIT: A relevant peer reviewed paper is this one, comparing the outcomes in children who received a vaccine containing thimerosal, and a vaccine in which thimerosal was absent.
Context Mercuric compounds are nephrotoxic and neurotoxic at high doses. Thimerosal, a preservative used widely in vaccine formulations, contains ethylmercury. Thus it has been suggested that childhood vaccination with thimerosal-containing vaccine could be causally related to neurodevelopmental disorders such as autism.
Objective To determine whether vaccination with a thimerosal-containing vaccine is associated with development of autism.
Design, Setting, and Participants Population-based cohort study of all children born in Denmark from January 1, 1990, until December 31, 1996 (N = 467 450) comparing children vaccinated with a thimerosal-containing vaccine with children vaccinated with a thimerosal-free formulation of the same vaccine.
Main Outcome Measures Rate ratio (RR) for autism and other autistic-spectrum disorders, including trend with dose of ethylmercury.
Results During 2 986 654 person-years, we identified 440 autism cases and 787 cases of other autistic-spectrum disorders. The risk of autism and other autistic-spectrum disorders did not differ significantly between children vaccinated with thimerosal-containing vaccine and children vaccinated with thimerosal-free vaccine (RR, 0.85 [95% confidence interval {CI}, 0.60-1.20] for autism; RR, 1.12 [95% CI, 0.88-1.43] for other autistic-spectrum disorders). Furthermore, we found no evidence of a dose-response association (increase in RR per 25 µg of ethylmercury, 0.98 [95% CI, 0.90-1.06] for autism and 1.03 [95% CI, 0.98-1.09] for other autistic-spectrum disorders).
Conclusion The results do not support a causal relationship between childhood vaccination with thimerosal-containing vaccines and development of autistic-spectrum disorders.
High doses of mercuric compounds are nephrotoxic and neurotoxic.1 Thimerosal, an organic compound that contains ethylmercury, has been widely used since the 1930s as a preservative in certain vaccines. In the 1990s, an increasing number of different vaccines containing thimerosal were introduced in immunization schedules around the world, and thus the average cumulative exposure to thimerosal in infants has increased in recent years. This has led to the suggestion that childhood vaccination with thimerosal-containing vaccines increases the risk of neurodevelopmental disorders, such as autism, attention-deficit/hyperactivity disorder, and language and speech delay.
In a recent independent review conducted by the Immunization Safety Committee, on behalf of the Institute of Medicine, it was concluded that the evidence was inadequate to accept or reject a causal relationship between thimerosal-containing vaccine and neurodevelopmental disorders.2 However, based on comparison with the toxicology of methylmercury, the biological plausibility of a link remained. Further research was recommended. We examined the hypothesized association by comparing children vaccinated with a thimerosal-containing pertussis vaccine with children vaccinated with the same pertussis vaccine formulated without thimerosal and following them with respect to development of autism and other autistic-spectrum disorders.
Full paper downloadable from here.
From that paper, we learn:
In our cohort, only 20755 (4.4%) children did not receive any whole-cell pertussis vaccine, 446695 (95.6%) were vaccinated at least once, 416081 (89.0%) were vaccinated twice, and 293 186 (62.7%) received 3 doses of whole-cell pertussis vaccine. Among those who received at least 1 thimerosal—containing pertussis vaccine (n= 138953), 118593 received 1 subsequent dose and 65725 received 2 subsequent doses of thimerosal-containing vaccine. Furthermore, 42032 children who received at least 1 dose of thimerosal—containing vaccine subsequently received at least 1 dose of thimerosal-free vaccine. In those receiving at least 1 dose of whole-cell pertussis vaccine, there were 407 cases of autism (303 receiving thimerosal-free and 104 receiving thimerosal—containing vaccine) and 751 cases of other autistic spectrum disorders (430 receiving thimerosal-free and 321 receiving thimerosal-containing vaccine).
If the anti-vaxers' assertions bore any connection to reality, the figures should have been wildly divergent from this.