ASSESSMENT OF MERCURY LEVELS IN INFANTS RECEIVING ROUTINE IMMUNIZATIONS

NIAID- supported studies at the University of Rochester and National Naval Medical Center in Bethesda, MD, assessed levels of mercury in the blood, hair, urine, and stool of 40 infants who received vaccines containing thimerosal and 20 infants who received vaccines without thimerosal, as controls. The infants studied were 6 months of age or younger. This study generated several important results.

• Mercury levels in blood and urine were low in all infants studied and in many cases too small to measure. There was no observed dose-dependent relationship between the level of thimerosal received through vaccination and the level of mercury in the body.
• Mercury levels in blood did not exceed, at any time, the blood levels that correspond to Environmental Protection Agency guidelines for exposure.
• Mercury levels in the stool of infants receiving vaccines containing thimerosal were relatively high compared to mercury levels in the stool of infants who were not exposed to thimerosal, providing evidence that mercury from thimerosal is eliminated in the stool of infants.

These results were recently published in The Lancet. For more information see http://www.niaid.nih.gov/factsheets/thimerosalqa.htm.