Activists who claimed that the preservative thimerosal - ethyl mercury - in vaccines was causing neurotoxic effects, including autism in children managed to push manufacturers and physicians into banning it in vaccines in the U.S. more than a decade ago. The result of their campaign was lower vaccination rates in the U.S. and higher costs for routine childhood vaccinations. Part of the higher costs is the result of switching to single dose vaccines that must be refrigerated as opposed to multidose vaccines that can be stored and transported without refrigeration.

Now the same activists are trying to get the World Health Organization (WHO) to favor a global ban on the preservative. However, many poor countries do not have the funds or facilities to manufacture, store and safely transport vaccines requiring refrigeration. More importantly, there is no scientific evidence that the tiny amounts of ethyl mercury in multidose vaccine vials causes any health problems. The American Academy of Pediatrics (AAP) has just issued a statement urging the WHO to approve vaccines that are made safe using thimerosal. The AAP's, "Global Vaccination Recommendations and Thimerosal" states:

Overwhelmingly, the evidence collected over the past 15 years has failed to yield any evidence of significant harm, including serious neurodevelopmental disorders, from use of thimerosal in vaccines. Dozens of studies from countries around the world have supported the safety of thimerosal-containing vaccines. Specifically, the Institute of Medicine, and others have concluded that the evidence favors rejection of a link between thimerosal and autism. Careful studies of the risk of other serious neurodevelopmental disorders have failed to support a causal link with thimerosal...

As advocates for the health of all children, we strongly support these efforts also. Immunization prevents ∼2.5 million deaths a year globally. Millions more deaths could be prevented if global immunization efforts are bolstered. The preponderance of available evidence has failed to demonstrate serious harm associated with thimerosal in vaccines. As such, we extend our strongest support to the recent Strategic Advisory Group of Experts recommendations to retain the use of thimerosal in the global vaccine supply.

Unfortunately, back in 1999 the AAP endorsed the removal of thimerosal from vaccines "out of an abundance of caution." The 1999 ruling by the AAP very likely stoked anti-vaccine hysteria with the result that thousands of kids suffered, and yes, some even died, needlessly from preventable infectious diseases. This is the precautionary principle in action.