The enduring controversial debate concerning the measles-mumps-rubella (MMR) vaccine and autistic spectrum disorder (ASD) has created gaps and unanswered questions for healthcare professionals as well as concerned parents.

Numerous medical research articles cannot infer conclusively that MMR vaccines are ruled out completely, or confirm them as the causative agent of ASD.

The purpose of this descriptive study is to discuss the current empirical literature on the significance of a relationship of ASD and mercury, and offer an overview of the studies to date in the interest of helping nurses to engage in informed debate with concerned parents.

The Relationship to Autism and Mercury-Containing Vaccines

The prevalence of autism has risen from one in about 2,500 children in the mid-1980s to one in about 300 children in 1 (Parker,Schwartz, Todd,  & Pickering,  2004), and although numerous sources now confirm an autism epidemic in the United States, the vast number of medical studies published on the increased incidence of ASD and mercury-containing vaccines has been conflictive, and many fail to report on the safety of vaccinations.

As reported by Fredrickson, Davis, Arnold, Kennen, Humiston et al. (2004),  approximately 73% of children in the United States are immunized, and most parents permit their children to receive immunizations, but  a sizable minority of parents have concerns about immunizations, and a few refuse some, or all vaccines (p. 444).

With one exception, the reviews published by the Institute of Medicine (IOM) in 1994, sought to determine whether routine childhood immunization has long-term adverse effects. For two-thirds of the possible vaccine-related adverse events examined, the IOM found insufficient data to determine a causal relationship, and has not published vaccine safety since.

Nurses take different approaches to sharing information and educating parents, and although nurses should be well versed in the literature of vaccine safety, medical research has provided few straightforward answers. Knowledge of current research is an effective tool to provide the best information possible, so parents can make the best possible choices.

The Issues of the U.S. Vaccine Schedule

Exposure to mercury has previously been shown to cause immune, sensory, neurological, motor, and behavioral dysfunctions similar to traits defining or associated with autistic disorders, and with similarities in neuroanatomy, neurotransmitters, and biochemistry (Geier & Geier, 2006). The risk targeted in the MMR, influenza, and hepatitis B prepared injections contained thimerasol, mercury based preservative present in mutli-dose vials (Katz, 2006).

Similarily, as public awareness increased on the neurological changes from the levels of heavy metal environmental contamination in the 1990’s,  the surge of incidence of ASD from 1993 to 2001, and the “onset of ASD often occurred contemporaneously with the immunization schedule at 12 to 18 months of age, led the association and the conviction that the MMR vaccine and ASD had a causative relationship” (Katz, 2006).

In 1998, Wakefield, Murch, Anthony, Linnell, Casson, et al. (1998), published a report that identified an associated gastrointestinal disease post MMR vaccine that resulted in developmental regression in eight previously normal children, and  thimerosal was named as the probable etiology of ASD ( (Katz, S.L., 2006).

Within a short time after the initial report by Wakefield et al. (1998), many parents in the United Kingdom and the United States opted to refuse the MMR vaccine for their infants and children.

Parents were proposing questions to health care professionals about weighing the safety of the mumps, measles, and rubella (MMR) vaccines, and the dangers of choosing not to immunize their children. Infants and children that were not immunized were becoming at risk for contracting mumps, measles, and rubella, and parents’ answers were not being address due to the lack of formal knowledge afforded  pediatricians and nurses.

Despite the argument that the MMR vaccine had been widely in use since 1971, and the current literature denied any connection to ASD, The American Academy of Pediatrics, and the US Public Health Service recommended the discontinuation of the use of thimerosal, as a preservative in multi-dose pediatric vaccines, and was entirely removed from the MMR vaccine in the U.S. by 2001 (Katz, 2006).