Global Justice and the Proposed Ban on Thimerosal-Containing Vaccines

* Abbreviations: HICs — : high-income countries LMICs — : low- and middle-income countries Thimerosal is an ethyl mercury–containing compound that has been used safely for >60 years as a preservative in multidose vials of vaccines to prevent bacterial and fungal contamination of those vials when they are repeatedly entered to withdraw doses.1,2 In the late 1990s, preservative-free single-dose vials were widely introduced into high-income countries (HICs). This was a precautionary move in response to theoretical concerns, now known to be unfounded, that ethyl mercury in thimerosal could build up in vaccine recipients’ bodies at a rate to similar methylmercury (a known toxin) causing toxicity.3 For low- and middle-income countries (LMICs), where the burdens of vaccine-preventable deaths are most profound, multidose vials of thimerosal-preserved vaccines are a critical part of immunization programs. Extensive additional resources associated with increased manufacturing, shipping, cold-chain storage, administration, and waste-handling infrastructure would be required by a move away from multidose vaccines; for example, a shift to single-dose vials would increase the annual cost of Pan American Health Organization– or UNICEF–supplied vaccines by >$300 million.4 In January 2013, governments are set to finalize the products and processes that will be prohibited in a multilateral environmental treaty, backed by the United Nations Environment Programme, which aims to restrict human and environmental exposure to mercury.5 As a mercury derivative, thimerosal could potentially be included within the treaty. Although supportive of the objectives of reducing human and environmental exposure to mercury, the World … Address correspondence to Shane K. Green, PhD, Sandra Rotman Centre, MaRS Building, South Tower, 101 College St, Suite 406, Toronto, ON, Canada, M5G1L7. E-mail: shane.green{at}srcglobal.org