A new international agreement to reduce mercury contamination of air and water was recently adopted by 140 countries, without a proposal that threatened to limit access to vaccines in much of the world. The credit goes to public health authorities and medical experts who challenged a provision blocking production of vaccines with the preservative thimerosal, the formulation necessary for efficient vaccine distribution in developing countries. Banning thimerosal in vaccines “would be a tragedy” that put millions of children at risk, stated Global Alliance for Vaccines & Immunization (GAVI) director Seth Berkley in the New York Times (Jan. 17, 2013).
The attack on efficient vaccine production and distribution arose from anti-thimerosal patient advocates, who sought to advance their own agenda through the United Nations Environmental Program initiative to limit mercury emissions. The UN campaign arose from a mercury poisoning catastrophe in Minimata, Japan that sickened and killed thousands in the 1950s. The main focus of the treaty is to curb toxic emissions of mercury from coal-fired power plants and certain gold-mining activities, and also reduce mercury in thermometers, batteries, dental fillings and other products. As the negotiations moved into their final stage last year, patient advocates who link thimerosal in vaccines to autism lobbied to ban the preservative from human and animal vaccines. Fortunately, the presentation of extensive scientific evidence on the safety and benefits of these products thwarted the effort.
Thimerosal is an organic substance containing ethyl-mercury, not the more toxic methyl mercury in harmful emissions. Even so, families concerned with neurodegenerative diseases such as autism insist that vaccines with the preservative are dangerous and should be removed. Such claims gained credibility in the late 1990s and prompted the Food and Drug Administration to instruct vaccine manufacturers to switch to thimerosal-free formulations for pediatric vaccines, a change that requires use of more costly single-dose vials to avoid contamination. Since 2001, FDA has not licensed any new vaccines for children that contain thimerosal and approved an influenza vaccine without the preservative in 2005. The agency sticks to this policy despite analyses by the Institute of Medicine (IOM) in 2001 and 2004 that found no link between vaccines and autism and new research discrediting the original claims.
But multi-dose vials of vaccines with thimerosal are common overseas, particularly in less developed regions where distribution and storage of single-dose vials would be difficult and much more costly. Without an effective preservative, Berkley noted, “far fewer vaccines would reach children in developing countries.”
The World Health Organization (WHO), the American Academy of Pediatrics (AAP), the IOM and GAVI countered the anti-thimerosal campaign by providing extensive documentation of thimerosal benefits, the importance of childhood immunization and the tragic consequences of such a ban in the mercury treaty. Eric Uram of the autism advocacy group SafeMinds blasted WHO, FDA and AAP, claiming that “children’s health took a backseat to special interests.”
In reality, the special interest advocates were the ones trying to hijack this international effort to improve global public health. Most parties regard the final document as only a first step towards reducing sources of mercury contamination, but at least it avoids erecting roadblocks to vaccination of children.