Photo Credit PHIL
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Thiomersal, better known in the U.S. as thimerosal, is an organomercury compound commonly used in multi-dose vials of vaccines as a preservative. Unlike many other preservatives, it does not adversely affect the potency of the vaccine.
Its use has none-the-less been controversial, and despite reassuring data, over the past decade the United States and the European Union have been phasing out the use of Thiomersal in many pediatric vaccines in what was deemed a `purely precautionary measure’.
Eliminating Thiomersal is an expensive proposition, however. It normally requires moving to single-dose injectables - something that may be feasible in richer countries - but not easily done in the developing world.
Next week’s Weekly Epidemiological Record (7/20) will have details of a meeting between the WHO and the Global Advisory Committee on Vaccine Safety (GACVS) which met last month to discuss Thiomersal preservatives.
Today, however, we get a preview from a Q&A FAQ on Thiomersal, posted on the World Health Organization’s website.
Citing new studies that continue to show the safety of Thiomersal in vaccines, a lack of viable alternatives, and the exorbitant cost of moving to single-use injectable (which could reduce the total number of vaccinated each year), the WHO reaffirms the safety, and necessity of using Thiomersal in vaccines.
The entire FAQ: Questions and Answers on new facts and figures on vaccines and the global mercury treaty is worth reading, but they sum up their position by saying:
Based on multiple expert reviews, WHO concluded that there would be a clear risk (if reformulation with alternative preservatives or with no preservatives is required) that some products would become unavailable – particularly the current low cost vaccines.
There would be a high risk of serious disruption to routine immunization programmes and mass immunization campaigns if currently thiomersal-
preserved vaccines are not available. The consequences would be a negative health impact, due to the predictable and sizable increase in mortality through lack of access to vaccines, for very limited environmental impact.
WHO reaffirms that thiomersal-containing vaccines are very safe. They are essential and currently irreplaceable components of immunization programmes, especially in developing countries, and removal of these products would disproportionately jeopardize the health and lives of the most disadvantaged children worldwide.
Given the widespread public angst over the use of Thiomersal in vaccines (even if the scientific data doesn’t support it) - were there a viable alternative - I have to believe that this committee would have seized it.
But in a world with increasing global health problems and ever-shrinking global health budgets, moving to single-use injectables is a luxury that the WHO, and the millions of children who would be denied vaccination, simply cannot afford.
