Vaccines, Mercury, & Autism

Trace amounts of a form of mercury called thimerosal have been used as a preservative in some vaccines. Some people have suggested that there may be a link between this preservative and autism. What happens when you look at all kids with autism in an entire country over a thirty-year period? Researchers at the University of Aarhus in Denmark scrutinized data from all of the children diagnosed with autism in Denmark between 1971 and 2000. The striking results were published in the September 2003 Pediatrics. While thimerosal was present in vaccines, autism rates were pretty stable. But when thimerosal was removed from vaccines in Denmark in 1992, autism rates went up, and continued to climb. While larger doses of mercury certainly harm neurodevelopment, the trace amounts used in vaccines could not be correlated with autism in this study. The latest reports from Britain also suggest that vaccines containing thimerosal are not harmful, and go so far as to suggest that those containing thimerosal are more effective. I find the Denmark study to be encouraging further evidence of the relative safety of trace amounts of thimerosal. Nevertheless, mercury is an active and toxic substance about which we still have much to learn. I continue to favor thimerosal-free vaccines. All of the routine vaccines for children in the U.S. are available without thimerosal.