""Merck, as well as other vaccine manufacturers, uses two well-established human cell lines to grow the virus for selected vaccines," Merck said in a statement to ABC News. "The FDA has approved the use of these cell lines for the production of these Merck vaccines." Other common vaccines, including those for chicken pox, hepatitis and rabies, are also propagated in cells originating from legally aborted human fetuses, according to the FDA. "These abortions, which occurred decades ago, were not undertaken with the intent of producing vaccines," said a spokeswoman for the U.S. Centers Disease Control and Prevention. The original cells were obtained more than 50 years ago and have been maintained under strict federal guidelines by the American Type Culture Collection, according to Merck."