Washington Federal health officials won't put new restrictions on the use of a mercury-based preservative in vaccines and other medicines, denying a petition that sought the limits because of health concerns.
A group called the Coalition for Mercury-free Drugs petitioned the Food and Drug Administration in 2004 seeking the restrictions on thimerosal, citing concerns that the preservative is linked to autism. In a reply dated Sept. 26 but made public only Tuesday, the FDA rejected the petition.
"Only a small number of licensed and approved products still contain thimerosal, and the available evidence supports FDA's conclusion that all currently licensed vaccines and other pharmaceutical drug products containing thimerosal are safe," Dr. Jeffrey Shuren, the FDA's assistant commissioner for policy, wrote in denying the petition.
Thimerosal, about 50 percent mercury by weight, has been used since the 1930s to kill microbes in vaccines. There have been suspicions that thimerosal causes autism. However, studies that tracked thousands of children consistently have found no association between the brain disorder and the mercury-based preservative. Critics contend the studies are flawed.