evidence: Vaccine ingredients, including the preservative thimerosal, do not cause autism. Ingredients in vaccines currently routinely recommended to the general population in the U.S.* have not been shown to cause any other adverse events. [...] Other vaccine ingredients including preservatives, adjuvants, or manufacturing residuals, can sound scary to the general public, especially when they are poorly understood. This has caused some understandable, albeit unfounded, concerns regarding the safety of these ingredients. Examples of this are aluminum and formaldehyde, which are known toxins for humans when consumed in large quantities. However, one must always keep the dosage in mind, as a great many things can be toxic with a high enough exposure. In the case of these vaccine ingredients, they present no danger in the miniscule quantities in which they are used in vaccines (which is typically much less than is found naturally in the body, common food or the environment), and serve only to stabilize the vaccine or enhance the immune response 4. More information is available on the FDA website (link). A full list of components by vaccine can be found on our Components page. [...] 11. Parker SK, Schwartz B, Todd J, Pickering LK. Thimerosal-containing vaccines and autistic spectrum disorder: a critical review of published original data. Pediatrics 2004; 114(3): 793-804.