Federal Activity – Food & Drug Administration Overview
As part of the Food and Drug Administration (FDA) Modernization Act, an assessment of thimerosal (a mercury containing vaccine preservative) use in vaccines was conducted from 1997 to 1999. The FDA investigation was unable to locate any clinical studies formally evaluating the use of thimerosal before its initial marketing in the 1930’s. The only study found was from 1931 where thimerosal was administered to individuals suffering from meningitis. The study was not designed to specifically examine toxicity; no clinical assessments were described nor were laboratory studies reported. In the paper, the authors acknowledge the clinician who treated the meningitis patients was not convinced of its efficacy stating “beneficial effects of the drug were not definitely proven.” Industry scientists noted in 1930 that a “wide range of toxicity and injury tests should be done” but they were not.
In 2002 the FDA nominated thimerosal to the National Toxicology Program (NTP) in March 2002 to further study whether there is a potential for thimerosal-preservative induced neurodevelopmental toxicity, to assess the comparative toxicity of ethyl- and methylmercury, to evaluate the metabolism and elimination of ethylmercury compared to methylmercury, and to evaluate the effect of intermittent intramuscular doses of thimerosal from vaccines compared with chronic low dose oral exposure to methylmercury.
The NTP nomination of thimerosal was reviewed by the Interagency Committee for Chemical Evaluation and Coordination (ICCEC) in April 2002. At that time the nomination was discussed within the framework of ongoing studies. In September 2002, the Board of Scientific Counselors reviewed the nomination to the NTP and endorsed the ICCEC’s recommendations to examine data from ongoing developmental studies on mercury and related compounds and to proceed with design efforts for potential studies. The ICCEC deferred the study FDA nominated to the NTP until ongoing studies of thimerosal and methylmercury kinetics in non-human primates (Burbacher et al, 2005, Comparison of blood and brain mercury levels in infant monkeys exposed to methylmercury or vaccines containing thimerosal, Environ Health Perspect. 113(8):1015-1021) and similar studies in mice (Berman et al, 2008, Low-level neonatal thimerosal exposure: Further evaluation of altered neurotoxic potential in SJL mice. Toxicol. Sci.i 101(2), 294-309) were completed.
Also, at this time several epidemiological studies were initiated or ongoing which examined whether there was any association of vaccines containing thimerosal-preservative with neurodevelopmental disorders, as well as studies researching blood mercury pharmacokinetics in human infants (Thompson et al, 2007, Early Thimerosal exposure and neuropsychological outcomes at 7 to 10 years, N. Engl. J. Med. 357: 1281-1292, Fombonne et al, 2006, Pervasive developmental disorders in Montreal, Quebec, Canada: Prevalence and links with immunizations, Pediatrics 118:e139-e150; Pichichero et al, 2008, Mercury levels in newborns and infants after receipt of thimerosal-containing vaccines, Pediatrics, 121: e208 – e214).
Due the the reduction of mercury in vaccine, the FDA is considering data from published studies to determine if gaps in knowledge remain that would need to be addressed and thus, whether it is justified to proceed with the deferred study in non-human primates nominated by the FDA to the NTP in 2002.
Burbacher study findings were that ethylmercury more rapidly converted to inorganic mercury in the brains of the primates, which resulted in increasing levels of inorganic mercury. Primates exposed to ethylmercury retained at least twice as much inorganic mercury in their brains compared to the primates exposed to methylmercury. Exposures to mercury were found to disrupt the growth and migration of neurons, with the potential to cause irreversible damage to the central nervous system. The Burbacher study clearly indicates that the toxicokinetics of thimerosal differ greatly from those of methylmercury. With the current safe standard for thimerosal being based on methylmercury and not ethylmercury, the Burbacher study demonstrates the necessity of the deferred study.
While use of thimerosal in vaccines has been reduced, the majority of influenza vaccines administered to children under six and pregnant women continue to be thimerosal containing and expose children to at least ten times over the safe standard. Thus, concern pertaining to the toxicokinetics of thimerosal continue to be relevant. In part, the charge of the National Toxicology Program (NTP) “is to evaluate agents of public health concern by developing and applying tools of modern toxicology and molecular biology.” Additionally, the executive summary of the nomination stated “that in order to provide a more complete assessment of the toxicity of thimerosal during the critical period of neurodevelopment, well designed studies are needed to address these gaps in knowledge in appropriate animal model(s).”
The language from the nomination suggests that toxicological studies in the form of animal models would be preferred determining criteria, while the mission statement for the NTP further reiterates that focus, putting into question the use of epidemological studies as a basis to go forward with the NTP’s investigation of thimerosal. SafeMinds has requested clarification on this point from the FDA as well as the NTP, and have been advised that the information is only available through FOIA. SafeMinds awaits the fulfillment of their FOIA request for clarification of the use of epidemiological studies, as well as a timeline on the review and studies under consideration.
Today, the scientific literature is flush with research that documents deleterious effects of thimerosal on numerous organ systems, including the immune, metabolic and nervous, in mammals and humans. These effects may vary depending on the dose, the genetics of the individual, and the timing of exposure. This research strongly suggests that ethyl mercury exposure from thimerosal containing vaccines given to infants or pregnant women has the potential to cause harmful effects.
Therefore, in the interest of precaution, removal of mercury from vaccines given to vulnerable populations is warranted. Actions that lead to removal of thimerosal, particularly given that sufficient supplies of mercury free vaccines are readily available, should be supported.
In addition, all of the recommendations for additional research from the Institute of Medicine Immunization Safety Review report: Thimerosal Containing Vaccines and Neurodevelopmental Disorders, 2001 should be conducted immediately. The 2004 report from the Institute of Medicine in this regard, Immunization Safety Review: Vaccines and Autism, did not fulfill the recommendations from the 2001 report, regarding clinical and biological science, and relied heavily on epidemiological studies containing serious design flaws and conflicts of interest.
SafeMinds Summary of Science, sumbitted to the NTP, is a brief summary of recently published science, conducted in the many fields of research recommended in the initial report by the Institute of Medicine in 2001, regarding thimerosal at doses which correspond to levels found in vaccines, or at concentrations that are likely to result from vaccine administration.
A brief summary of research supporting other forms of mercurials and their role in autism, autism behaviors and known biological anomalies have been included in the science summary, as mercury from all vectors is known to impact development.
SafeMinds also started new inquiries a year ago based on the FDA’s published policy on the principal protections of vaccine safety that requires the firm to test samples from each lot for safety, potency and purity, and carries out spot-testing of its own.
Our inquiries were simple, did FDA spot testing encompass post licensure verification of the manufacturer’s purification process in the removal of mercury in the production of vaccines and how often did they perform spot testing post licensure? The FDA stated they can conduct spot checks but would not confirm that spot checks have ever been conducted post licensure and stated that current litigation prevented further comment. Emails also confirmed that the FDA relies heavily on data furnished by the manufacturer in any review of vaccines with specific test results available via the Freedom of Information Act (FOIA), which is currently experiencing a backlog of requests. SafeMinds currently has two outstanding FOIA with FDA to gain insight into reduction of thimerosal in vaccines and independent verification of the purification process in use to remove mercury for currently licensed vaccines.
That requests for clarification of published policy regarding vaccine safety are denied and all communications with FDA officials on the matter ended with a disclaimer stating that the communication does not constitute a formal opinion or position undermines public trust in vaccine safety and impedes transparency. The attitude was noted in the FDA Science and Mission at Risk Report from the Subcommittee on Science and Technology issued late last year that stated the “FDA is engaged in reactive regulatory priority setting or a fire-fighting regulatory posture instead of pursuing a culture of proactive regulatory science,”.
SafeMinds supports banning the use of mercury (thimerosal) in all prescription and over the counter products approved by the FDA due to the failure of the FDA to:
- conduct adequate safety studies prior to marketing thimerosal as a vaccine preservative;
- account for thimerosal’s track record as an ineffective and toxic preservative;
- safeguard against mercury exposure from thimerosal-containing vaccine administration resulting in mercury levels where adverse outcomes are documented to occur;
- significant deposition of inorganic mercury in the brain from exposure to thimerosal crossing the blood brain barrier;
- lead with effective U.S policy, which is falling behind other countries on this important health issue and is not in keeping with the Institute of Medicine’s 2001 recommendations;
- state a preference for mercury-free vaccines resulting in reduced public confidence in the National Immunization Program.
Articles of Interest
SafeMinds Director Deirdre Imus Huffington Posts on the FDA