Poison In Our Vaccines

By Lyn Redwood
Issue 115, November/December 2002

More than 60 years ago, the Food and Drug Administration (FDA) approved a little-known product, thimerosal, to be used as a preservative. Today, many parents question if this product is responsible for the current epidemic of children diagnosed with learning disabilities and autism.

Thimerosal
Current thinking suggests that exposure to mercury comes primarily from environmental and dietary sources, dental amalgams, and rare catastrophic events. Recently, however, another common and pervasive source of mercury exposure has been identified. Called thimerosal, it was first approved as an additive by the FDA in the 1930s and has been utilized as a preservative to prevent bacterial contamination in a number of blood and biological products, including vaccines, immune globulins, and over-the-counter eye and nose drops.

The danger that thimerosal presents is that it contains 49.5 percent ethyl mercury by weight. Mercury is a potent human toxicant and has long been the source of many serious health problems. It is especially toxic to the rapidly developing fetal and infant brain. Federal agencies have published acceptable levels for exposure; but in actual fact mercury is a poison at any level. Chemically, thimerosal is a water-soluble, cream-colored crystalline powder. In the human body it is metabolized to ethyl mercury and thiosalicylate. The literature on thimerosal metabolism and excretion is old, and toxicological information is limited. In the past there have been case reports of toxicity and death following inadvertent massive exposures to thimerosal.

The FDA's Discovery
The FDA Modernization Act, signed into law in 1997, included an amendment requiring the agency to compile a list of drugs and foods that contain intentionally introduced mercury compounds and to provide a quantitative and qualitative analysis of the mercury compounds on the list. One may ask why the FDA did not routinely perform this task. The FDA's mission is to ensure purity, safety, potency, and efficacy of individual products, yet such analyses have never been a required part of the permitting process. In its review, which took two years to complete, the FDA discovered that infants who receive vaccines containing thimerosal may be exposed to more mercury than recommended by federal guidelines for total mercury exposure.

Infant vaccines that routinely contained thimerosal were DPT (diphtheria-pertussis-tetanus), hepatitis B, and Hib (Hemophilus influenzae type b). Following the vaccination schedule recommended by the Centers for Disease Control (CDC), infants were exposed to anywhere from 0.0 to 187.5 mcg of ethyl mercury, depending on the vaccine manufacturer, and total exposure over 18 months could be as high as 237.5 mcg. The dose the Environmental Protection Agency (EPA) deems allowable is 0.1 mcg per kilogram per day. If an average 5 kg-infant received all thimerosal-containing vaccines at his two-month visit, his exposure that day would be 62.5 mcg ethyl mercury--125 times as great as the EPA guideline.

In its analysis, the FDA multiplied EPA's daily exposure levels of 0.1 mcg per kilogram by 180 days, even though the exposures had occurred on only four days during this time period. It is perplexing that the FDA chose to average an infant's total exposure to mercury over the first six months of life as though children were being exposed on a daily basis, and reported that amounts were only slightly above one of the federal guidelines. According to toxicologists, because of the inherent pharmokinetics of mercury and its long half-life in the body, the effect of a large injected dose cannot be calculated as though it were ingested in small amounts over a longer period of time. This method of analysis inaccurately minimizes the levels of exposure. If one were to look at the mercury in thimerosal from a daily dose perspective, no one vaccine containing thimerosal would meet EPA's guidelines for safe exposure. A simple analogy can be made that since one may safely consume four Tylenol a day in six-hour intervals for a month, consuming 120 Tylenol in one day would be equally safe. (In fact, it would be a fatal dose.) At the same time the FDA findings were released, the American Academy of Pediatrics (AAP) published an interim report to physicians on thimerosal in vaccines. In the report, the AAP and Public Health Service agreed that the use of thimerosal-containing vaccines should be reduced or eliminated, stating that any potential risk was of concern.1 While this report discussed much of the uncertainty regarding the potential effect of mercury exposure in vaccines, it clearly stated that there was no evidence of harm having occurred from such exposure. The report also said, "Infants and children who have received thimerosal-containing vaccines do not need to have blood, urine, or hair tested for mercury since the concentrations would be quite low and would not require treatment." Without such tests, of course, it was impossible to know for a fact that there was no "evidence of harm."

Historical Perspective
It is interesting to note that thimerosal was introduced only a few years before Leo Kanner, MD, described a new mental disorder that differed "markedly and uniquely from anything reported" before.2 In its early history autism was diagnosed more frequently in affluent families, but by the 1970s it had become more evenly distributed socioeconomically. This apparent widening in demographics paralleled the increasing availability of vaccines to all children through federally sponsored programs.