The article was written by Baker and published in 2008. He focused on the controversy surrounding the use of thimerosal in vaccines. Rather than studying the relevance of thimerosal to autism, he concentrated on three aspects that led to the stated controversy. Firstly, he discussed about the introduction of thimerosal as a preservative in vaccines (Baker 244). Secondly, he focused on the delay, after the discovery of toxic effects of mercury, in accusing thimerosal as a causative agent for autism (Baker 244). Finally, he discussed the factors that resulted in linking vaccines to autism (Baker 244).
In late 19th and early 20th centuries, the concern over the contamination of vaccines in poor hygienic conditions had led researchers to try various preservatives for vaccines that can prevent bacterial contamination (Baker 244). In due course of time, the emergence of organomercurials as effective agents in combating bacterial contamination of vaccines slowly resulted in the research on and inclusion of thimerosal, a white crystalline powder in the form of ethylmercury bound to thiosalicylate, in vaccines as a preservative (Baker 245). The advantages of thimerosal were depicted in its safety at tested low doses and efficiency in maintaining the biological effects of vaccines over existing preservatives like phenol and cresol (Baker 245).
However, in light of the discovery of severe toxic effects of organomercurials, methylmercury in particular, people started suspecting the safety of thimerosal (Baker 246). To be precise, the Minamata disaster of 1950s and the Iraq’s disaster in early 1970 that resulted from consumption of food contaminated with methylmercury led to wide spread concerns over the toxicity of organomercurials (Baker 246&7). In these incidents, many children were identified with developmental neurological disorders (Baker 247).
Moreover, various experiments on the effects of methylmercury on human health resulted in different conclusions. As a result, the permissible dose of methylmercury was set differently by various agencies in the US, such as Federal Drug Administration (FDA) and Environmental Protection Agency (EPA) that ranged from 0.1 to 0.4 µg per Kg body weight per day (Baker 247).
Meanwhile, the change in the perspective of researchers from defining autism in psychoanalytical terms to biomedical terms, and broadening the characteristics of the disorder with labels such as pervasive developmental disorders and autistic spectrum disorders resulted in detection of more children with autism (Baker 248&9). Also, the detection of autism in children who had vaccinations recently led to the opinion among parental groups than professionals that thimerosal could be the cause for autism (Baker 249).
Moreover, exaggerated reports on thimerasol’s relation to autism that were widespread on Internet and media made people to campaign against the use of thimerosal in vaccines (Baker 249&250). However, the Center for Biologics Evaluation and Research (CBER) made a risk assessment of thimerosal and concluded that it was harmless at doses used in vaccines, but should be avoided in vaccines soon in view of rising concerns (Baker 250).
All in all, the author provided comprehensive information regarding factors that resulted in controversies over the use of thimerosal in vaccines.
Works Cited
Baker, Jeffrey P. “Mercury, Vaccines and Autism: One Controversy, Three Histories.” American Journal of Public Health 98.2 (2008): 244-253.