GAVI praises exclusion of vaccine preservative from ban

The GAVI Alliance expressed its praise on Friday for the U.N.'s decision to recognize the safety of a mercury-based vaccine preservative by excluding it from a list of banned substances in a mercury treaty.

Delegates at the United Nations Environment Program specifically included thimerosal, a widely used vaccine preservative, as an exception in a treaty on the release of mercury into the environment. Allowing thimerosal to count as an exception in the treaty was endorsed by the World Health Organization, UNICEF, GAVI and other civil organization societies.

Thimerosal has been used widely since the 1930s to prevent fungal and bacterial contamination of multi-dose vials of vaccines. Of 2.5 million deaths prevented annually through vaccines, 1.4 million are prevented using thimerosal-preserved vaccines.

Because thimerosal contains small amounts of ethylmercury, it was included in UNEP treaty negotiations. The negotiations were meant to rid the planet of risks posed to human health and the environment from mercury.

Unlike methylmercury, which can move through the food chain and accumulate in the body, ethylmercury is broken down by the body and flushed out within a few days.

The treaty specifically excludes vaccines containing thimerosal as a preservative and focuses on restricting major sources of environmental mercury releases.

More than 140 countries and 900 delegates were involved in the final negotiations to protect access to vaccines.