COVID-19 vaccine ingredients: FOI release

Information request and response under the Freedom of Information (Scotland) Act 2002

Information requested

You asked for the following information:

1) Has thimerosal (mercury) actually been tested for safety in human consumption?

2) Being a so called preservative in a vaccine this would be extremely toxic being injected straight into the bloodstream would it not?

3) Who does the checks for vaccine ingredients in Scotland nowhere else we have our own toxicological experts I want this stuff investigated properly?


The answers to your questions, as at the time of writing (28/10/2021), are as follows:

1) The World Health Organization (WHO) and the European Medicines Agency (EMA, previously EMEA) have both stated that there is no evidence of risk from thiomersal in vaccines. Any and all medicines or vaccines go through detailed testing for safety, quality and efficacy before they can be made available in the UK.

2) In the US, UK and Europe, thiomersal was removed from vaccines as a precaution between 2003 and 2005. This was in line with the global goal of reducing environmental exposure to mercury from all sources. However, there was no evidence that thiomersal in vaccines caused harm. Thiomersal contains a compound called ethyl mercury, but concern about mercury in the environment has centred on a different compound called methyl mercury, which accumulates in the food chain and in the human body.

More detailed information can be found on the US National Institute of Allergy and Infectious Disease. A study from 2008 showed that the ethyl mercury in thiomersal does not appear to accumulate in the bodies of even very small babies. It is cleared from the blood in 30 days, and the evidence suggests that it is passed out in the baby’s stool.

Furthermore, a 2014 Australian study of over a million children found no evidence of a link between thiomersal in vaccines and autism development.

3) The Medicines and Healthcare products Regulatory Agency (MHRA) are the UK-wide regulator of medicines and vaccines.

You will also wish to be aware that thiomersal is not present in any of the annual flu vaccines currently in use in the UK.

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Please quote the FOI reference
Central Enquiry Unit
Phone: 0300 244 4000

The Scottish Government
St Andrews House
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