Actually, the mercury based preservative, thimerosal has been taken out of almost all childhood vaccines. I pulled this blurb from an article in the Journal of American Physicians and Surgeons:
"Despite its removal from many childhood vaccines, thimerosal is still routinely added to some formulations of influenza vaccine administered to U.S. infants, as well as to several other vaccines (e.g. tetanus-diphtheria and monovalent tetanus) administered to older children and adults."
Despite the risks (there is risk in everything you do--like when you get in your car and drive), the benefit out-weighs the risk. All of those lovely things we are vaccinating against are now seeing a resurgence as more people are declining to vaccinate. Since thimerosal has been removed from most vaccinations, there has been a corresponding drop in the autism cases. I hope you would carefully consider the pros and cons. It is truly safer now than it was for even my children 10 years ago, and my guys are very normal....Good luck and hope this info helps.