Mercury In Medicine Report
Mr. Speaker, I submit the following report prepared by the staff of the Subcommittee on Human Rights and Wellness, Committee on Government Reform. This report is the result of a three- year investigation initiated in the Committee on…
Mr. Speaker, I submit the following report prepared by the staff of the Subcommittee on Human Rights and Wellness, Committee on Government Reform. This report is the result of a three- year investigation initiated in the Committee on Government Reform.
Mercury in Medicine--Taking Unnecessary Risks
I. Executive Summary
Vaccines are the only medicines that American citizens are
mandated to receive as a condition for school and day care
attendance, and in some instances, employment. Additionally,
families who receive federal assistance are also required to
show proof that their children have been fully immunized.
While the mandate for which vaccines must be administered is
a state mandate, it is the Federal Government, through the
Centers for Disease Control and Prevention (CDC) and its
Advisory Committee for Immunization Practices that make the
Universal Immunization Recommendations to which the majority
of states defer when determining mandates. Since the early to
mid-1990s, Congress has been concerned about the danger posed
by mercury in medical applications, and in 1997, directed the
Food and Drug Administration (FDA) to evaluate the human
exposure to mercury through foods and drugs.
In 1999, following up on the FDA evaluation and pursuant to
its authority, the House Committee on Government Reform
initiated an investigation into the dangers of exposure to
mercury through vaccination. The investigation later expanded
to examine the potential danger posed through exposure to
mercury in dental amalgams. This full committee investigation
complemented and built upon the investigations initiated by
two of its subcommittees. In January 2003, the investigation
continued in the newly formed Subcommittee on Human Rights
and Wellness.
A primary concern that arose early in the investigation of
vaccine safety was the exposure of infants and young children
to mercury, a known toxin, through mandatory childhood
immunizations. This concern had been raised as a possible
underlying factor in the dramatic rise in rates of late-onset
or ``acquired'' autism. The symptoms of autism are markedly
similar to those of mercury poisoning.
Significant concern has been raised about the continued use
of mercury in medical applications decades after the
recognition that mercury can be harmful, especially to our
most vulnerable population--our children. This report will
address one form of mercury in medical applications,
Thimerosal, as a preservative in vaccines.
In July 2000, it was estimated that 8,000 children a day
were being exposed to mercury in excess of Federal guidelines
through their mandatory vaccines.
One leading researcher made the following statement to the
Committee in July 2000:
``There's no question that mercury does not belong in
vaccines.
``There are other compounds that could be used as
preservatives. And everything we know about childhood
susceptibility, neurotoxicity of mercury at the fetus and at
the infant level, points out that we should not have these
fetuses and infants exposed to mercury. There's no need of it
in the vaccines.''
The Food and Drug Administration's (FDA) mission is to
``promote and protect the public health by helping safe and
effective products reach the market in a timely way, and
monitoring products for continued safety after they are in
use.'' However, the FDA uses a subjective barometer in
determining when a product that has known risks can remain on
the market. According to the agency, ``at the heart of all
FDA's product evaluation decisions is a judgment about
whether a new product's benefits to users will outweigh its
risks. No regulated product is totally risk-free, so these
judgments are important. FDA will allow a product to present
more of a risk when its potential benefit is great--
especially for products used to treat serious, life-
threatening conditions.''
This argument--that the known risks of infectious diseases
outweigh a potential risk of neurological damage from
exposure to thimerosal in vaccines, is one that has
continuously been presented to the Committee by government
officials. FDA officials have stressed that any possible risk
from thimerosal was theoretical: that no proof of harm
existed. Upon a thorough review of the scientific literature
and internal documents from government and industry, the
Committee did in fact find evidence that thimerosal posed a
risk. The possible risk for harm from either low dose chronic
or one time high level (bolus dose) exposure to thimerosal is
not ``theoretical,'' but very real and documented in the
medical literature.
Congress has long been concerned about the human exposure
to mercury through medical applications. As a result of these
concerns, in 1997, Congress instructed the FDA to evaluate
the human exposure to mercury through drugs and foods.
Through this Congressionally mandated evaluation, the FDA
realized that the amount of ethylmercury infants were exposed
to in the first six months of life through their mandatory
vaccinations exceeded the Environmental Protection Agency's
(EPA) limit for a closely associated compound methylmercury.
The FDA and other Federal agencies determined that in the
absence of a specific standard for ethylmercury, the limits
for ingested methylmercury should be used for injected
ethylmercury. The Institute of Medicine, in 2000, evaluated
the EPA's methylmercury standard and determined that based
upon scientific data that it, rather than the FDA's, was the
scientifically validated safe exposure standard.
Rather than acting aggressively to remove thimerosal from
children's vaccines, the FDA and other agencies within the
Department of Health and Human Services (HHS) adopted an
incremental approach that allowed children to continue to be
exposed to ethylmercury from vaccines for more than two
additional years. In fact, in 2001, the Centers for Disease
Control and Prevention (CDC) refused even to express a
preference for thimerosal-free vaccines, despite the fact
that thimerosal had been removed from almost every childhood
vaccine produced for use in the United States.
On three occasions in the last 15 years, changes have been
made to vaccine policies to reduce the risk of serious
adverse effects. First, a transition from oral polio vaccine
to injected polio was accomplished in the United States to
reduce the transmission of vaccine-induced polio. Second, an
acellular pertussis vaccine was developed and a transition
from DTP to DTaP was accomplished to reduce the risk of
pertussis--induced seizures in children. And third, when the
Rotashield vaccine for rotavirus was linked to a serious
bowel condition (intersucception), it was removed from the
U.S. market. Ethylmercury has been largely removed from every
major childhood vaccine manufactured for use in the United
States, except the influenza vaccine, which continues to
contain trace amounts.
This success, however, does not change the fact that
millions of American children were exposed to levels of
mercury through vaccines that exceeded comparable federal
guidelines. Many parents, and a growing number of scientists,
believe that this mercury exposure may have contributed to
the explosive growth in autism spectrum disorders, and
neurological and behavioral disorders that this country has
experienced. The scientific evidence in this area is
considered by some to still be inconclusive, in large part
due to the lack of serious, effective inquiry by our health
agencies. The federal government has an obligation to
vigorously pursue the necessary research to determine the
extent of the impact of these heightened exposures to
ethylmercury on our population.
A second concern that arose during the investigation was
the continued use of mercury in dental amalgams. Mercury has
been used as a component in dental fillings since the Civil
War era. The American Dental Association and its member
dentists have taken a position that the mercury in fillings,
which are considered toxic until placed in the tooth, and is
considered toxic when removed from the mouth, is completely
safe while in the human mouth. This position seems counter
even to the ADA-funded research that shows the daily release
of small amounts of mercury vapors in the human mouth where
dental amalgams are present, as well as minute chipping and
swallowing of the mercury fillings over time.
Babies and young children are exposed to this additional
mercury. As developing fetuses, babies are exposed to mercury
through the placenta. If pregnant women have mercury
amalgams, they are unknowingly excreting low levels of
mercury on a daily basis to their fetuses. Additionally,
children who receive dental services through Medicaid are
also potentially exposed to mercury. When these children need
dental fillings, because of the low cost, only mercury
amalgams are available for use. This concern remains under
investigation by the Subcommittee on Human Rights and
Wellness.
II. Findings and Recommendations
A. Findings
Through this investigation of pediatric vaccine safety, the
following findings are made:
1. Mercury is hazardous to humans. Its use in medicinal
products is undesirable, unnecessary and should be minimized
or eliminated entirely.
2. For decades, ethylmercury was used extensively in
medical products ranging from vaccines to topical ointments
as preservative and an anti-bacteriological agent.
3. Manufacturers of vaccines and thimerosal, (an
ethylmercury compound used in vaccines), have never conducted
adequate testing on the safety of thimerosal. The FDA has
never required manufacturers to conduct adequate safety
testing on thimerosal and ethylmercury compounds.
4. Studies and papers documenting the hyperallergenicity
and toxicity of thimerosal (ethylmercury) have existed for
decades.
5. Autism in the United States has grown at epidemic
proportions during the last decade. By some estimates the
number of autistic children in the United States is growing
between 10 and 17 percent per year. The medical community has
been unable to determine the underlying cause(s) of this
explosive growth.
6. At the same time that the incidence of autism was
growing, the number of childhood vaccines containing
thimerosal was growing, increasing the amount of ethylmercury
to which infants were exposed threefold.
7. A growing number of scientists and researchers believe
that a relationship between the increase in
neurodevelopmental disorders of autism, attention deficit
hyperactive disorder, and speech or language delay, and the
increased use of thimerosal in
vaccines is plausible and deserves more scrutiny. In 2001,
the Institute of Medicine determined that such a relationship
is biologically plausible, but that not enough evidence
exists to support or reject this hypothesis.
8. The FDA acted too slowly to remove ethylmercury from
over-the-counter products like topical ointments and skin
creams. Although an advisory committee determined that
ethylmercury was unsafe in these products in 1980, a rule
requiring its removal was not finalized until 1998.
9. The FDA and the CDC failed in their duty to be vigilant
as new vaccines containing thimerosal were approved and added
to the immunization schedule. When the Hepatitis B and
Haemophilus Influenzae Type b vaccines were added to the
recommended schedule of childhood immunizations, the
cumulative amount of ethylmercury to which children were
exposed nearly tripled.
10. The amount of ethylmercury to which children were
exposed through vaccines prior to the 1999 announcement
exceeded two safety thresholds established by the Federal
government for a closely related substance--methylmercury.
While the Federal Government has established no safety
threshold for ethylmercury, experts agree that the
methylmercury guidelines are a good substitute. Federal
health officials have conceded that the amount of thimerosal
in vaccines exceeded the EPA threshold of 0.1 micrograms per
kilogram of bodyweight. In fact, the amount of mercury in one
dose of DTaP or Hepatitis B vaccines (25 micrograms each)
exceeded this threshold many times over. Federal health
officials have not conceded that this amount of thimerosal in
vaccines exceeded the FDA's more relaxed threshold of 0.4
micrograms per kilogram of body weight. In most cases,
however, it clearly did.
11. The actions taken by the HHS to remove thimerosal from
vaccines in 1999 were not sufficiently aggressive. As a
result, thimerosal remained in some vaccines for an
additional two years.
12. The CDC's failure to state a preference for thimerosal-
free vaccines in 2000 and again in 2001 was an abdication of
their responsibility. As a result, many children received
vaccines containing thimerosal when thimerosal-free
alternatives were available.
13. The Influenza vaccine appears to be the sole remaining
vaccine given to children in the United States on a regular
basis that contains thimerosal. Two formulations recommended
for children six months of age or older continue to contain
trace amounts of thimerosal. Thimerosal should be removed
from these vaccines. No amount of mercury is appropriate in
any childhood vaccine.
14. The CDC in general and the National Immunization
Program in particular are conflicted in their duties to
monitor the safety of vaccines, while also charged with the
responsibility of purchasing vaccines for resale as well as
promoting increased immunization rates.
15. There is inadequate research regarding ethylmercury
neurotoxicity and nephrotoxicity.
16. There is inadequate research regarding the relationship
between autism and the use of mercury-containing vaccines.
17. To date, studies conducted or funded by the CDC that
purportedly dispute any correlation between autism and
vaccine injury have been of poor design, under-powered, and
fatally flawed. The CDC's rush to support and promote such
research is reflective of a philosophical conflict in looking
fairly at emerging theories and clinical data related to
adverse reactions from vaccinations.
B. Recommendations
1. Access by independent researchers to the Vaccine Safety
Datalink database is needed for independent replication and
validation of CDC studies regarding exposure of infants to
mercury-containing vaccines and autism. The current process
to allow access remains inadequate.
2. A more integrated approach to mercury research is
needed. There are different routes that mercury takes into
the body, and there are different rates of absorption.
Mercury bioaccumulates; the Agency for Toxic Substances and
Disease Registry (ATSDR) clearly states: ``This substance may
harm you.'' Studies should be conducted that pool the results
of independent research that has been done thus far, and a
comprehensive approach should be developed to rid humans,
animals, and the environment of this dangerous toxin.
3. Greater collaboration and cooperation between federal
agencies responsible for safeguarding public health in regard
to heavy metals is needed.
4. The President should announce a White House conference
on autism to assemble the best scientific minds from across
the country and mobilize a national effort to uncover the
causes of the autism epidemic.
5. Congress needs to pass legislation to include in the
National Vaccine Injury Compensation Program (NVICP)
provisions to allow families who believe that their
children's autism is vaccine-induced the opportunity to be
included in the program. Two provisions are key: First,
extending the statute of limitations as recommended by the
Advisory Commission on Childhood Vaccines from 3 to 6
years. Second, establishing a one to two-year window for
families, whose children were injured after 1988 but who
do not fit within the statute of limitations, to have the
opportunity to file under the NVICP.
6. Congress should enact legislation that prohibits federal
funds from being used to provide products or pharmaceuticals
that contain mercury, methylmercury, or ethylmercury unless
no reasonable alternative is available.
7. Congress should direct the National Institutes of Health
to give priority to research projects studying causal
relationships between exposure to mercury, methylmercury, and
ethylmercury to autism spectrum disorders, attention deficit
disorders, Gulf War Syndrome, and Alzheimer's Disease.
III. Thimerosal Has Been Used In Vaccines And Other Medical Products
For Decades
A. A brief description of mercury
Mercury is a silver-colored metal, which unlike any other
metal, is a liquid at room temperature. It flows so easily
and rapidly that it is sometimes called quicksilver. The
chemical symbol for Mercury is Hg.
Mercury has many properties that have made it popular for a
number of commercial uses. For example, mercury expands and
contracts evenly when heated or cooled. It also remains
liquid over a wide range of temperatures and does not stick
to glass. These properties have prompted its use in
thermometers. Mercury conducts electricity and is used in
some electric switches and relays to make them operate
silently and efficiently. Industrial chemical manufacturers
use mercury in electrolysis cells to charge substances with
electricity. Mercury vapor, used in fluorescent lamps, gives
off light when electricity passes through it. Before its
health effects were well understood, mercury compounds were
widely used in such common products as house paints and
paper.
Various alloys (mixtures of metals) containing mercury have
many uses. Mercury alloys are called amalgams. These would
include silver amalgam, a mixture of silver and mercury that
dentists use to fill cavities in teeth.
Mercury comes in many different forms--organic, inorganic,
elemental, and metallic. As a result of its many practical
uses, mercury became widespread in the environment. However,
it is now widely recognized that overexposure to all forms of
mercury can harm the central nervous system (brain) and the
renal system (kidneys). This has led to regulatory actions to
reduce the exposure of humans to mercury on many fronts.
According to the Agency for Toxic Substances and Disease
Registry (ATSDR): ``The nervous system is very sensitive to
all forms of mercury.''
B. Thimerosal, which contains ethylmercury, has been used in medicines
since the 1930's
In addition to its many commercial applications, mercury
has been used in a number of medical applications. One such
product that came into frequent use during the twentieth
century was thimerosal. Thimerosal is an organic compound
made up of equal parts of thiosalicylic acid and
ethylmercury. It is 49.6 percent ethylmercury by weight.
Thimerosal was developed by Dr. Morris Kharasch (1895-1957;
Ukraine/USA), a chemist and Eli Lilly fellow first at the
University of Maryland (1922-1927) and then at the University
of Chicago. He filed for a patent on June 27, 1929, for what
he described as an alkyl mercuric sulfur compound
(thimerosal), which he felt had potential as an antiseptic
and antibacterial product. Dr. Kharasch was considered a
pioneer in his field, contributing to the development of
plastics and the creation of synthetic rubber. He also went
on to found the Journal of Organic Chemistry.
In October 1929, Eli Lilly and Company registered
thimerosal under the trade name Merthiolate. Merthiolate was
used to kill bacteria and prevent contamination in antiseptic
ointments, creams, jellies, and sprays used by consumers and
in hospitals. Thimerosal was also used in nasal sprays, eye
drops, contact lens solutions, immunoglobulins, and most
importantly here--vaccines.
Thimerosal was patented the same year that Alexander
Fleming discovered penicillin. But because it took more than
a decade for penicillin to be fully developed, and large-
scale production to begin, thimerosal was widely used in the
interim. To the medical profession, who were without
antibiotics during the 1930's and 1940's, thimerosal
(marketed as Merthiolate) and other antiseptic products were
gladly received.
Dr. H. Vasken Aposhian, Professor of Molecular and Cellular
Biology and Pharmacology, University of Arizona discussed
thimerosal's history during Congressional testimony:
``In the early thirties, in fact the 1940's and up until
the mid-1950's, mercurials were used in medicine . . . The
medical community . . . had nothing better to use. They had
nothing better to use as a preservative at that time than
thimerosal. And I would venture the opinion that it has just
been going on because no one has objected to it. And there's
no need for it any longer. And I don't know any medical
community or scientific community that would agree to the
need for having thimerosal in any vaccine.''
Thimerosal became the most widely used preservative in
vaccines and other medical products. Its use in antiseptic
products to prevent infections was common. By the time that
the FDA conducted its review of mercury in 1999, more than 50
licensed vaccines contained thimerosal.
While thimerosal became widely used, there were repeated
references in the scientific literature to the lack of
substantial understanding of its safety. In numerous
publications, researchers suggested that caution be taken in
human exposure. For example, a paper published in 1934 noted,
``little is known about the mercuric compounds when
inoculated into humans. It is therefore preferable to use the
minimum amount of this preservative.''
Eli Lilly ceased its production of vaccines in 1974.
Shortly after the FDA advisory committee determined that
thimerosal in over-the-counter products was no longer
``generally recognized as safe,'' Eli Lilly and other
companies chose to cease production of products such as
merthiolate and mercurichrome. By the mid-1980's, Eli Lilly
was completely out of the business of manufacturing or
selling thimerosal-containing products. However, thimerosal
continued to be used in vaccines. In the 1990's, thimerosal
was manufactured by numerous companies, including Sigma-
Aldrich, Inc.; EM Industries, Inc. (now EMD Chemicals Inc.,
the North American extension of Merck KGaA); Dow Chemical
Company; Spectrum Laboratory Products, Inc. (formerly
Spectrum Quality Products, Inc.); and GDL International, Inc.
C. Mercury is a known neurotoxin, but methylmercury has been more
carefully studied than ethylmercury
After more than a century of research, it has become widely
accepted in the scientific and medical communities that
mercury is a neurotoxin. While debate continues over what
levels of exposure to mercury are safe, it is unquestioned
today that overexposure to mercury in any form can cause
neurological and renal damage. There is also a growing
consensus around the theory that some individuals are more
susceptible to harm from mercury than others, confounding
efforts to adopt a population-level threshold for safe levels
of mercury in the environment. A research paper published in
2002 summarized the scientific consensus very succinctly:
``Mercury and its compounds are cumulative toxins and in
small quantities are hazardous to human health.''
Because of its many commercial applications and its
widespread presence in the environment, methylmercury
received the lion's share of the attention in the scientific
community during the twentieth century. A concise history of
the early development of scientific knowledge about
methylmercury is found in Dr. Thomas Clarkson's, ``The Three
Modern Faces of Mercury'':
``The first methylmercury compounds were synthesized in a
chemical laboratory in London in the 1860s. Two of the
laboratory technicians died of methylmercury poisoning. This
so shocked the chemical community that methylmercury
compounds were given a wide berth for the rest of the century
. . . early in the twentieth century the potent anti-fungal
properties . . . were discovered, leading to applications to
seed grains, especially for cereal crops . . . Despite the
widespread use, few cases of poisoning were reported for the
first half of the twentieth century. However, in the late
1950s and 1960s serious outbreaks of alkyl mercury poisoning
(methylmercury) erupted in several developing countries . . .
Also in the late 1950s, evidence emerged of environmental
damage from treated grain. It was observed in Sweden that
predatory birds were developing neurological disorders . . .
analysis . . . indicated a sharp rise in mercury levels.''
Public health concerns about methylmercury in the edible
tissue of fish suddenly erupted in 1969 when fish from Lake
St. Clair bordering Michigan were found to have high levels.
This and other findings . . . have maintained public health
concerns over this form of mercury.''
As a result of these emerging concerns, public health
officials worldwide began researching methylmercury. Today,
the scientific literature is replete with evidence on toxic
effects of methylmercury. In 2000, the National Academy of
Sciences published Toxicological Effects of Methylmercury,
which concluded:
Methylmercury is highly toxic.
The data indicate that the adverse effects of methylmercury
exposure can be expressed in multiple organ systems
throughout the lifespan.
The research in humans on the neurodevelopmental effects of
methylmercury is extensive.
Damage to renal tubules and nephron has been observed
following human exposure to inorganic and organic forms of
mercury. Symptoms of renal damage have been seen only at
mercury exposures that also caused neurological effects.
The cardiovascular system appears to be a target for
methylmercury toxicity in the same dose range as
neurodevelopmental effects--at very low mercury exposures.
Studies in humans on the carcinogenic effects of
methylmercury are inconclusive.
Methylmercury may increase human susceptibility to
infectious disease and autoimmune disorders by damaging the
immune system.
Methylmercury may adversely affect the reproductive system.
The medical literature is replete with references to the
dangers to methylmercury:
``The major toxic effects of methylmercury are on the
central nervous system. Its toxic action on the developing
brain differs in both mechanism and outcome from its action
on the mature organ . . . the action of methylmercury on
adults is characterized by a latent period between exposure
and onset of symptoms. The period can be several weeks or
even months, depending on the dose and exposure period . . .
paresthesia, numbness or a `pins and needles' sensation is
the first symptom to appear at the lowest dose. This may
progress to cerebella ataxia, dysarrthia, constriction of the
visual fields, and loss of hearing. . . . Cardiovascular
disease . . . accelerated progression of carotid
arteriosclerosis.''
The research is explicit that fetal brains are more
sensitive than the adult brains to the adverse effects of
methylmercury, which include:
Severe brain damage
Delayed achievement of developmental milestones
Neurological abnormalities such as brisk tendon reflexes
Widespread damage to all areas of the fetal brain, as
opposed to focal lesions seen in adult tissue
Microcephaly
Purkinje [neuron] cells failed to migrate to the cerebellum
Inhibition of both cell division and migration, affecting
the most basic process in brain development
Additionally, elevation in both systolic and diastolic
blood pressure in seven year olds correlated with prenatal
exposure to methylmercury . . . indicative of later
cardiovascular problems.
Despite the fact that ethylmercury has been widely used in
common medical treatments, ranging from vaccines to nasal
sprays to ointments, comparatively little research has been
done on its health effects. The few studies that have been
done tend to indicate that ethylmercury is just as toxic as
methylmercury.
The FDA never required the pharmaceutical industry to
conduct extensive safety studies on thimerosal or
ethylmercury. It appears that our Federal regulatory
framework (the FDA and its predecessor organizations) failed
to require manufacturers to prove thimerosal was safe. They
failed to require industry to conduct adequate testing to
determine how thimerosal is metabolized. The FDA failed to
require that industry conduct studies to determine the
maximum safe exposure level of thimerosal. These basic issues
should have been proven prior to the introduction of
thimerosal into the marketplace, but more than 70 years after
its introduction, these issues have still not been adequately
addressed. The introduction of thimerosal appears to have
been based on a single uncontrolled and poorly reported human
study in the 1920s, possibly in combination with animal and
laboratory studies. However, this sole human study was not a
true safety study and produced a faulty foundation on which
to build a robust vaccine program in which young children
would be forced to be repeatedly injected with multiple doses
of ethylmercury.
During the pre-antibiotic 1920's, meningitis was a killer.
Out of sheer desperation, the treating physician at a
hospital dealing with dozens of patients facing a sure death
from meningitis, tested thimerosal on about two-dozen
patients. He injected the thimerosal intravenously, without
apparent side effects. However, the treatment was not
successful and all of the patients died. The leading industry
scientists of that era involved in thimerosal research
published a paper that made a brief reference to this study:
``Merthiolate was injected intravenously into 22 persons . .
. these large doses did not produce any anaphylactoid or
shock symptoms.'' In the paper, the authors acknowledge that
Dr. K.C. Smithburn, the clinician who treated the meningitis
patients, was not convinced of its efficacy: ``beneficial
effects of the drug were not definitely proven.'' Drs. Powell
and Jamieson also noted in 1930 that a ``wide range of
toxicity and injury tests should be done.'' There is no
evidence that Drs. Powell and Jamieson took their own advice
and conducted studies to address these concerns.
As a result, in 1999, 70 years after the product was first
licensed, neither the FDA nor the industry had followed
through on determining a safe exposure level to thimerosal or
ethylmercury. Thus, when facing a policy decision on
thimerosal and vaccines, the FDA had to work from an
``assumption'' that the toxicity of ingested methylmercury
was the same as injected ethylmercury.
One study that compared the toxicology of ethyl and
methylmercury was published in 1985 in the Archives of
Toxicology, written by researchers from the Toxicology Unit
of the Medical Research Council of England. The researchers
exposed rats to ethyl and methylmercury to ``compare total
and inorganic mercury concentrations in selected tissues,
including the brain, after the daily administration of methyl
or ethylmercury and to relate these findings to damage in the
brain and kidneys.'' This study found that both ethyl and
methylmercury caused damage to the brains and the kidneys. It
also found that male and female rats were affected
differently:
``It has been well documented that one of the first toxic
effects of methylmercury in rats is depressed weight gain or
even weight loss . . . based on this criteria, ethylmercury
proved to be more toxic than methylmercury . . . in both
sexes . . . the concentration of total mercury (the sum of
organic and inorganic mercury) and organic mercury was
consistently higher in the blood of ethylmercury-treated rats
. . . both alkymercurials damaged the dorsal root ganglia and
9.6 mg Hg/kg/day ethylmercury caused more damage than 8.0 mg
Hg/kg/day methylmercury. Ethylmercury was more renotoxic than
methylmercury . . . tubular dilation was frequently present .
. . in kidneys . . . both damage and mercury deposits
were more widely spread in ethylmercury-treated rats.''
While there is frequent reference to the paucity of science
in understanding the harm that ethylmercury can do, there is
more understanding in the scientific community than
government officials have shared with the Committee. The
following dialogue between Congressman Dave Weldon (R-FL) and
Dr. David Baskin during the Committee's December 10, 2002
hearing sheds a great deal of light onto the true nature of
ethyl versus methylmercury.
Dr. Weldon: ``I have a couple of questions for Dr. Baskin
about ethylmercury versus methylmercury. I have had some
people say that data on methylmercury is fairly good, but we
don't have good data on ethylmercury. I take it from your
testimony there is actually quite a bit of data on
ethylmercury and it's as toxic as methylmercury.''
Dr. Baskin: ``There is more data, more and more data on
ethylmercury. The cells that I showed you dying in cell
culture are dying from ethylmercury. Those are human frontal
brain cells. You know, there has been a debate about . . .
ethyl versus methyl. But from a chemical point of view, most
chemical compounds that are ethyl penetrate into cells better
than methyl. Cells have a membrane on them, and the membrane
is made of lipids, fats. And ethyl as a chemical compound
pierces fat and penetrates fat much better than methyl. And
so, you know, when I began to work with some of the Ph.D.s in
my laboratory and discuss this everyone said, `oh gosh, you
know, we've got to adjust for ethyl because it's going to be
worse; the levels are going to be much higher in the cells.'
So . . . I think at best they're equal, but it's probably
highly likely that they are worse. And some of the results
that we are seeing in cell culture would support that.''
Dr. Baskin explained that according to scientific research
in humans and animals, brain tissue absorbs five times more
mercury than other tissues in the body.
Dr. Weldon: ``Now, you said several times in your testimony
that uptake in the brain is probably much higher than in
other tissues. What do you base that statement on?''
Dr. Baskin: ``Well, the literature on methylmercury is much
better than ethyl on this issue. And if you look at the
studies, the brain is 2 percent of the body weight but took
10 percent of the exposure. So that's a five-fold
preferential uptake.''
The testimony of Dr. Baskin builds upon earlier testimony
that the Committee received from recognized experts in
chemistry, toxicology and pharmacology. It includes the
following statement from Dr. H. Vasken Aposhian, Professor of
Molecular and Cellular Biology, and Pharmacology at the
University of Arizona, who provided the Committee the
following information about the evidence on mercury toxicity
at the July 18, 2000 hearing:
``The mercury amalgams in your mouth, the so-called silver
fillings, contain 48 to 50 percent of elemental mercury.
These fillings continuously emit mercury vapor, which will go
to the brain and is converted to mercuric mercury . . .
Certain fish contain methylmercury; again, very rapidly taken
up from the GI tract, transported quickly to the brain, and
converted very slowly to mercuric mercury . . . thimerosal,
which again will be taken up by the brain and quickly
converted to mercuric mercury--all three forms are
neurotoxic.
``By neurotoxic, we mean it will damage nerves and it will
damage brain tissues.
``Let me just say as a final statement that there is no
need to have thimerosal in a vaccine.''
In making a presentation to the Institute of Medicine's
Immunization Safety Review Committee, in July 2001, the
former Director of the Environmental Toxicology Program at
the National Institutes of Health, Dr. George Lucier,
proffered the following conclusions:
Ethylmercury is a neurotoxin.
Infants may be more susceptible than adults.
Ethylmercury should be considered equipotent to
methylmercury as a developmental neurotoxin. This conclusion
is clearly public health protective.
Ethylmercury exposure from vaccines (added to dietary
exposures to methylmercury) probably caused neurotoxic
responses (likely subtle) in some children.
While the debate over whether ethyl or methylmercury is
more toxic will probably not be resolved in the near future,
a consensus appears to be emerging that exposure to these
different types of mercury cannot be considered in isolation.
Rather, witnesses before the Committee stressed that in
determining safe levels of mercury exposure, the cumulative
level of exposure to all types of mercury must be considered.
Dr. Jeffrey Bradstreet made the following observation at the
July 19, 2002 hearing:
``More concerning to me in the Institute's treatment of
mercury problems, was the almost complete absence of regard
for compounding effect of thimerosal on preexisting mercury
levels. The NHANES Study from the CDC had already established
that perhaps one in ten children is born to mothers with
elevated mercury burden.''
D. Because of its toxicity, mercury has become heavily regulated.
As the dangers of mercury have become better understood,
the United States and other governments around the world have
taken actions to reduce the release of mercury into the
environment. In 1972, the federal government halted the use
of mercury compounds for many industrial uses, such the paint
used on the hulls of ships and compounds used to prevent the
growth of fungi in lumber, because the mercury had leached
into the environment and found its way into the human food
chain.
In 1972, while certain agencies within the federal
government recognized that mercury was a cumulative poison
that damaged brain cells, the FDA's vaccine division seems to
have ignored the issue until 1999.
1. The EPA is Regulating the Release of Mercury Into the Environment
The Environmental Protection Agency (EPA) under the Clean
Air Act regulates airborne emissions of mercury. In December
2000, the EPA announced that it would issue new regulations
on the emissions of mercury from coal and oil-fired power
plants. That action was taken because, ``mercury has been
identified as the toxic of greatest concern among all the air
toxics emitted from power plants.''
More recently, President Bush announced on February 14,
2002, that mercury emissions from power plants would be
reduced 69% under his Clear Skies Initiative. Under this
plan, mercury emissions would be reduced from the current
level of 48 tons nationally to 15 tons by 2018. The EPA also
regulates mercury emissions from municipal waste combustors,
medical waste incinerators, and hazardous waste incinerators.
The EPA works both domestically and internationally to
reduce mercury exposures in the environment. The ``Canada-
United States Strategy for the Virtual Elimination of
Persistent Toxic Substances in the Great Lakes Basin'' is an
example of these activities.
2. Different Limits to Exposure to Mercury Have Been Established by
Different Agencies
In the course of regulating mercury, different government
agencies have established different minimum risk levels for
daily exposure to mercury. Exposure to less than the minimum
risk level is believed to be safe, while exposure that
exceeds that level is believed to increase the chances of
injury. All of the levels apply specifically to ingested
methylmercury.
The EPA established the most conservative level: 0.1
micrograms of mercury per kilogram of body weight per day.
Under this standard, an 11-pound baby (roughly 5 kilograms)
could be exposed to up to 0.5 micrograms of mercury per day
and be considered safe. This exposure standard is a marked
contrast to the 25 micrograms of mercury that was contained
in several childhood vaccines until very recently.
The most lenient federal minimum risk level for mercury is
the FDA's, which sets its limit at 0.4 micrograms per
kilogram of body weight per day. (The United Nations' World
Health Organization sets a slightly higher limit of 0.47
micrograms per kilogram of bodyweight per day.) Falling in
between is the U.S. Agency for Toxic Substances and Disease
Registry (ATSDR) at 0.3 micrograms.
In 2000, the National Academy of Sciences issued a report
titled, Toxicological Effects of Methylmercury, validating
the EPA's lower limit as a ``scientifically appropriate level
that adequately protects the public.''
------------------------------------------------------------------------
Methylmercury guidelines -------------------------------------------------------------------------
Guideline
value for
maximum
daily
consumption
(g/kg/day)
Agency (micrograms Guideline `type'
per kilogram
of
bodyweight
per day) ------------------------------------------------------------------------ EPA 0.1 Reference dose (RfD). ATSDR 0.3 Minimal risk level. FDA 0.4 Tolerable daily intake. WHO 0.47 Provisional daily tolerable
intake (converted from a
weekly tolerable intake). ------------------------------------------------------------------------
The Committee repeatedly heard from government officials
that merely exceeding the guideline was not cause for
concern. One Merck official, in teaching a Grand Rounds
session to staff in November of 1999, postulated that the
minimum risk level would need to be multiplied by ten to
reach a level at which harm would be expected through
exposure. Dr. Roberta McKee of Merck wrote:
``A number of environmental and public health agencies have
set a Minimum Risk Level (MRL) for toxic substances. An MRL
for ingestion is conceptually equivalent to the Reference
Dose of the US Environmental Protection Agency, the
Acceptable Daily Intake of the US FDA, and the Tolerable
Daily Intake of the WHO. Any exposure to the substance below
the MRL is assured to be safe, while exposure to ten times
the MRL is assumed to place one at risk of overdose. Exposure
at or near the MRL is assumed to be safe but should trigger
deliberate and careful review.''
Based on Dr. McKee's explanation, many babies were exposed
to levels of mercury that ``placed one at risk of overdose,''
and were exposed to amounts well over ten times the EPA's
scientifically validated reference dose. For example, at a
recent Committee hearing, Chairman Dan Burton (R-IN)
discussed his own family's experience with vaccine injuries:
``My grandson received vaccines for nine different diseases
in one day. He may have been exposed to 62.5 micrograms of
mercury in one day through his vaccines. According to his
weight, the maximum safe level of mercury he should have been
exposed to in one day is 1.5 micrograms, so that is 41 times
the amount at which harm can be caused.''
According to the analysis of Dr. McKee, based on the
methylmercury ingestion guidelines, the Chairman's grandson
would have
exceeded the ``ten times the MRL'' and therefore was placed
``at risk of overdose.'' In fact, with a 62.5 microgram
exposure alone, the EPA, ATSDR, and FDA levels would have
been exceeded by 10 times. Because the FDA chose not to
recall thimerosal-containing vaccines in 1999, in addition to
all of those already injured, 8,000 children a day continued
to be placed ``at risk for overdose'' for at least an
additional two years.
It should also be noted that none of the Federal guidelines
on mercury exposure have been included specific provisions
for safe exposure limits for infants and children. It is
widely accepted that infants and young children would be five
times more sensitive to the toxic effect of mercury or other
neurotoxins than adults. ``Exposures early in life are
reasonably of greater health concern . . . because of greater
brain organ susceptibility.''
The FDA has conceded in recent years that many children
received doses of ethylmercury through their vaccinations
that exceeded the EPA's minimal risk level for methylmercury.
However, it is also clear that many infants received doses of
ethylmercury that exceeded the FDA's higher threshold.
3. Warnings Have Been Issued About Mercury in Seafood
The FDA's actions regarding the risk of medical exposures
to mercury have differed greatly from their actions regarding
food exposures to mercury. The agency has a long history of
issuing warnings to the public to monitor their fish
consumption due to concerns about mercury exposure. During
the 1990's, the FDA repeatedly issued warnings advising
pregnant women and young children to avoid certain fish, or
to limit their consumption of these fish because of their
mercury content. In September of 1994, the FDA issued an
advisory entitled, ``Mercury in Fish: Cause for Concern?'' in
which they stated:
``Swordfish and Shark taste great--especially grilled or
broiled. But reports which state that these and other large
predatory fish may contain methylmercury levels in excess of
the Food and Drug Administration's 1 part per million (ppm)
limit has dampened some fish lover's appetites. . .`there is
no doubt that when humans are exposed to high levels of
methylmercury that poisoning and problems in the nervous
system can occur' . . . the types of symptoms reflect the
degree of exposure . . .
``During prenatal life, humans are susceptible to the toxic
effects of high methylmercury exposure because of the
sensitivity of the developing nervous system . . .
Methylmercury easily crosses the placenta, and the mercury
concentration rises to 30 percent higher in fetal red blood
cells than in those of the mother . . . none of the studies
of methylmercury poisoning victims have clearly shown the
level at which newborns can tolerate exposure . . . Pregnant
women and women of child bearing age, who may become
pregnant, however, are advised by FDA experts to limit their
consumption of shark and swordfish to no more than once a
month.''
Similarly, a March 2001 FDA advisory states:
``Some fish contain high levels of a form of mercury called
methylmercury that can harm an unborn child's developing
nervous system if eaten regularly. By being informed about
methylmercury and knowing the kinds of fish that are safe to
eat, you can prevent any harm to your unborn child and still
enjoy the health benefits of eating seafood.. . . While it is
true that the primary danger from methylmercury in fish is to
the developing nervous system of the unborn child, it is
prudent for nursing mothers and young children not to eat
these fish as well.''
In addition to the public advisories, the FDA, in January
of 2001, established an aggressive ``Education Plan on Methyl
Mercury.'' In January 2001, Associate FDA Commissioner
Melinda Plaiser, responding to Congressman William J. Coyne
(D-PA) regarding the National Academy of Sciences' report on
Methylmercury, wrote:
``[L]et me reiterate, the FDA's commitment to protecting
the public's health and the environment regarding mercury.''
Furthermore, in their training materials for employees, the
FDA reflects a slightly different emphasis on mercury's
toxicity than what they presented to the Committee:
``People are exposed every day to a tremendous number of
substances in our environment. These substances include major
and trace elements that may or may not be essential for
sustaining life . . . Other elements are not known to be
essential but are constantly found in living tissues . . . Of
these elements that have no known nutritional value, some
have been found to be toxic at concentrations well below
those of other nonessential elements. Lead, cadmium, and
mercury are examples of elements that are toxic when present
at relatively low levels.''
Other HHS entities have taken very strong mercury reduction
positions. For example, the National Institutes of Health's
(NIH) Division of Safety has initiated a program to make the
NIH mercury-free. According to the Division's own website:
``Elemental (metallic) mercury and its compounds are toxic
and exposure to excessive levels can permanently damage or
fatally injure the brain and kidneys. Elemental mercury can
also be absorbed through the skin and cause allergic
reactions. Ingestion of inorganic mercury compounds can cause
severe renal and gastrointestinal toxicity. Organic compounds
of mercury such as methylmercury are considered the most
toxic forms of the element. Exposures to very small amounts
of these compounds can result in devastating neurological
damage and death.
``For fetuses, infants, and children, the primary health
effects of mercury are on neurological development. Even low
levels of mercury exposure, such as result from a mother's
consumption of methylmercury in dietary sources, can
adversely affect the brain and nervous system. Impacts on
memory, attention, language and other skills have been found
in children exposed to moderate levels in the womb.
``The Campaign for a Mercury Free at the NIH seeks to
eliminate, as far as possible, the use of mercury in NIH
facilities; to encourage the use of safer alternatives in
biomedical research; to increase general awareness of mercury
hazards; and to prevent mercury pollution.''
This NIH program has initiated a ``Hatters Pledge'' program
to recruit scientists to reduce the use of mercury at the NIH
and to educate children on the dangers of mercury.
The NIH Hatters Pledge:
I will:
Improve my awareness of mercury hazards and how to reduce
them.
Replace mercury thermometers and other mercury-containing
items with non- or low-mercury alternatives if suitable
alternatives are available.
Dispose of mercury wastes following NIH procedures.
Report spills of mercury.
On the NIH campus, call the Fire Department (911) who are
the NIH hazardous material (HAZMAT) emergency responder.
Off campus, call the local fire department or facility's
hazardous material (HAZMAT) emergency responder.
Have areas that might have been contaminated by mercury
surveyed and decontaminated, if necessary.
4. Over the Course of Two Decades, the FDA Slowly Removed Ethylmercury
From Many Medicinal Products
In 1980, the FDA began a lengthy regulatory process to
remove ethylmercury products from over-the counter products
like topical ointments, diaper rash creams, and
contraceptives. Topical ointments are products used on the
skin either for the treatment or prevention of skin
infections or inflammatory processes. They are typically
divided into four categories, first-aid products to be
applied to small superficial wounds to prevent infection;
skin wound protectant to provide a protective barrier to
small wounds; antibiotic or antifungal creams to prevent
or treat overt skin infection; and anti-inflammatory
agents used to reduce inflammation and inhibit pruritis.
In 1980, the FDA asked their Over-the-Counter (OTC) Review
Panel to conduct a massive review of OTC products. The panel
opted to divide the task into categories, one of which was a
review of OTC products containing ethylmercury.
As a result of the panel's work, in 1982, the FDA issued a
proposed rule to ban thimerosal from OTC topical ointments.
In addition to raising questions about the general
effectiveness of thimerosal for preventing infections, the
FDA found that thimerosal was too toxic for OTC use. Among
the findings that they published were the following:
At the cellular level, thimerosal has been found to be more
toxic for human epithelial cells in vitro than mercuric
chloride, mercuric nitrate, and merbromim (mercurichrome).
It was found to be 35.3 times more toxic for embryonic
chick heart tissue than for staphylococcus aureus.
Delayed hypersensitivity in 50 percent of the guinea pigs
tested, indicating that thimerosal is highly allergic and
that it is reasonable to expect humans to be equally
allergic.
The FDA concluded that while it has been suggested that
hypersensitivity may be due to the thiosalicylate portion of
the molecule and not the ethylmercury, this was not
confirmed.
They noted a Swedish study which found in healthy subjects
the following levels of hypersensitivity to thimerosal: 10%
of school children; 16% of military recruits; 18% of twins,
and 26% of medical students.
In 1982, the FDA advisory panel concluded that thimerosal
was not generally recognized as safe: ``The Panel concludes
that thimerosal is not safe for OTC topical use because of
its potential for cell damage if applied to broken skin and
its allergy potential. It is not effective as a topical
antimicrobial because its bacteriostatic action can be
reversed.''
Despite this strong finding, the FDA's proposed ban on the
OTC use of thimerosal was not finalized until 1998, 18 years
later. At the time of the OTC review, the industry chose not
to challenge the findings of the Panel regarding the toxicity
of thimerosal in OTC products. It is unclear why the FDA
chose to do nothing for 18 years after a ``not generally
recognized as safe'' finding.
Although the FDA went through that 18-year regulatory
process to remove thimerosal from topical ointments,
apparently no one at the FDA was prompted to review the use
of thimerosal in vaccines. Action to remove thimerosal from
vaccines did not begin until 1999, in response to the
Congressionally mandated review. This will be discussed in
more detail later in this report.
At the time of the 1999 FDA review on thimerosal, it was
learned that over 50 vaccines
contained thimerosal. On July 9, 1999, the American Academy
of Pediatrics joined the U.S. Public Health Service in
issuing a joint statement recommending the removal of all
thimerosal from vaccines. On its website, the FDA provides
the following rationale for its policy on thimerosal:
``Over the past several years, because of an increasing
awareness of the theoretical potential for neurotoxicity of
even low levels of organomercurials, and because of the
increased number of thimerosal-containing vaccines that have
been added to the infant immunization schedule, concerns
about the use of thimerosal in vaccines and other products
have been raised. Indeed, because of these concerns, the Food
and Drug Administration has worked with, and continues to
work with, vaccine manufacturers to reduce or eliminate
thimerosal from vaccines.''
In 1999, the FDA was criticized by some for not taking more
forceful action to remove thimerosal from vaccinations; as a
result of the FDA decision to seek a gradual removal, many
children continued to receive injections of the DTaP, Hib,
and Hepatitis B vaccine that contained mercury well into
2001. Mercury-containing vaccines manufactured in the United
States, up to today, continue to be administered to infants
and small children in the United States and abroad.
E. Thimerosal is still used in some medical products
While the FDA has taken steps over the last 20 years to
remove ethylmercury from topical ointments and most pediatric
vaccines, a number of medical products continue to contain
this preservative.
Some nasal and ophthalmic products containing thimerosal
remain on the market.
About 75 percent of the flu vaccines, recently recommended
to be given to children as young as six months, contain at
least trace amounts of thimerosal.
Many adult vaccines contain thimerosal.
Vaccines containing thimerosal continue to be manufactured
in the United States and delivered through the World Health
Organization (WHO) to Third World Countries. The WHO has
continued to require the use of multi-dose vials and to use
preservatives, including thimerosal, to address storage and
transportation issues.
Of additional concern to the Committee, but not discussed
in detail within this report, is the continued use of
thimerosal in adult vaccines. There is a growing emphasis on
adult immunizations, including getting boosters to childhood
immunizations. Additionally, all new military recruits,
active duty, and reserve forces that are deploying overseas
are routinely given a large number of vaccines, many
containing ethylmercury. These vaccines are often given
consecutively and all in the same day.