Thiomersal, a preservative used in vaccines and bugbear of the anti-vaccinators, has been given a clean bill of health [PDF] by the Committee on Safety of Medicines:

‘Three new studies reinforce CSM advice from 2001 that there is no evidence of neurological adverse effects caused by thiomersal in vaccines according to the routine UK immunisation schedule. The balance of benefits and risks of thiomersal-containing vaccines therefore remains overwhelmingly positive.’