An exception to this is the influenza
vaccine, which is available in a variety of formulations, some of which contain Thimerosal, while others do not.
Although there is no clear scientific evidence that small amounts of Thimerosal in vaccines cause harm, in July 1999, leading U.S. public health and medical organizations and
vaccine manufacturers agreed that Thimerosal should be reduced or eliminated from vaccines as a precautionary measure.