Letters: Compounds proven safe for vaccines

Published on Saturday 28 November 2009 19:12

IN RELATION to Richard Derek Porter's comment titled "Deadly toxin in swine flu jab" (Debate, 22 November), ethylmercury (in the form of thiomersal) has been used in some vaccines for decades.

It is an important component in one of the swine flu vaccines in use in the UK to prevent bacterial contamination in the multi-dose vaccine vial once opened.

There is no credible evidence linking the small amount of thiomersal in vaccines to neurological disorders such as autism, Alzheimer's disease or multiple sclerosis. Indeed, several large population-based studies have failed to support the alleged links with autism.

The claim that thiomersal was withdrawn from childhood vaccines five years ago due to links with brain damage is simply inaccurate. The presence of thiomersal was not the reason the UK switched vaccines at the time, we simply switched to using different types of vaccine antigen. The new vaccines happened to be thiomersal-free.

There is a general shift towards reducing, or removing, thiomersal from medicines wherever possible, to reduce overall environmental exposure to mercury compounds – not because of a safety concern. European regulators continue to accept that there may be a need to use thiomersal in vaccines (as in the current situation).

It is equally inaccurate to claim that the squalene included in the vaccine is linked to the development of auto-immune disorders. Squalene is a natural oil found in plants, animals and in humans too. More than 45 million doses of a seasonal flu vaccine which also contains squalene have been used in other countries with no safety concerns. The World Health Organisation has fully reviewed the safety of squalene in vaccines and concluded that any fears over its safety are unfounded.

Dr June Raine, Director of Vigilance and Risk Management of Medicines, Medicines and Healthcare products Regulatory Agency (MHRA)