Vaccines

Health Care Without Harm Position on Thimerosal in Vaccines

Vaccination programs provide important public health benefits. Health Care Without Harm (HCWH) recognizes that the continuity and ongoing development of essential vaccination programs are key to achieving global public health. We also recognize the importance of responding to concerns about Thimerosal in vaccines.

Thimerosal contains a kind of organic mercury called ethylmercury, used in vaccines as a preservative. Methylmercury, another kind of organic mercury, is a potent developmental neurotoxicant. Although not as thoroughly studied, ethylmercury is similar enough to methylmercury and has properties sufficient to raise legitimate concerns about its impact on the developing brains of children who are exposed to thimerosal in vaccines.

HCWH supports a precautionary approach regarding the use of thimerosal in vaccines, based on available scientific information.

• Despite the lack of conclusive scientific evidence of harm from thimerosal, enough plausible concern has been raised to justify reformulating vaccine preparations so that they do not require thimerosal.
• This conclusion is justified because organic mercury is a neurodevelopmental toxicant and there are viable alternatives to vaccine formulation without sacrificing safety or efficacy.
• Regulators, public health officials and pharmaceutical companies have recognized this and moved to phase-out thimerosal use in the US and in several European countries.
• Such phase-outs, by switching to single-dose vaccines that do not require thimerosal as a preservative, are positive steps, but do not address the broader problem of multi-dose vaccine preparations in developing countries, where thimerosal use continues.
• In this regard, viable options for the delivery of multi-dose vaccines in developing countries should be developed as a matter of priority. This effort should be led by the World Health Organization, with participation from other intergovernmental agencies, national governments, pharmaceutical companies, international NGOs and foundations.