evidence: Despite widespread misleading reporting about links between the measles–mumps–rubella vaccine and autism from the end of the 1990s, there is no evidence that any vaccines or their components cause autism101,102. Indeed, the evidence now overwhelmingly shows that there is no increased risk of autism in vaccinated populations. Thiomersal (also known as thimerosal) is an ethyl mercury-containing preservative that has been used widely in vaccines since the 1930s without any evidence of adverse events associated with it, and there is also no scientific evidence of any link between thiomersal and autism despite spurious claims about this102. Thiomersal has been voluntarily withdrawn from most vaccines by manufacturers as a precautionary measure rather than because of any scientific evidence of lack of safety and is currently used mainly in the production of whole-cell pertussis vaccines.