Autism-thiomersal claim dismissed
The Health Protection Agency has dismissed claims by US researchers of a link between the rise in autism and thiomersal in vaccines.
Professor Richard Deth from Northeastern University in Boston found that thiomersal, aluminium, lead and alcohol all inhibited cellular pathways in neuroblastoma cells in vitro causing problems with methylation a process that regulates gene expression.
In a paper published in Molecular Psychiatry online and widely reported in the national media, Professor Deth concluded that the enzyme inhibited by the toxins methionine synthase was likely to have a role in disorders where children had impaired attention, such as autism.
He said his findings added 'mechanistic plausibility' to the possibility that vaccines were responsible for the rise in autism by 'linking the actions of thiomersal to a biological process that could account for clinical features of the disorder'.
But Dr Liz Miller, head of the immunisation division at the Government's Health Protection Agency, said any relevance to developmental disorders was 'purely hypothetical'.
She added: 'The epidemiological studies conducted to date have shown no evidence of risk and their conclusions are not affected by this laboratory-based study.'
In the UK, thiomersal is still used in diphtheria, tetanus, whole-cell pertussis and some flu and hepatitis B vaccines.