Thimerosal Containing Vaccines
Part I: In the Dark
March 14, 2011
Part 2: The WHO
This series on thimerosal-containing vaccines (TCV) is a critical
review of the subject and what is known about it
at this time.
Thimerosal is not my primary area of interest. I
therefore promise to be extra careful documenting the facts and even more
careful commenting on them.
Because the CDC only promotes vaccines
and vaccination, the write-up about Thimerosal in vaccines on the CDC web site
is relatively short:
Thimerosal is a mercury-containing preservative used in some
vaccines and other products since the 1930's. There is no convincing
evidence of harm caused by the low doses of thimerosal in vaccines, except
for minor reactions like redness and swelling at the injection site.
However, in July 1999, the Public Health Service agencies, the American
Academy of Pediatrics, and vaccine manufacturers agreed that thimerosal
should be reduced or eliminated in vaccines as a precautionary measure.
This is not exactly true. Thimerosal was not only used in
some vaccines; it was used in
most if not all vaccines “since the
1930’s”. It is only later that the mercury preservative was not used in Live
Virus Vaccines (LVV) and even later that
unit-dose vaccines without preservative became available, under duress.
The second sentence is no less problematic. Objective evidence of harm in vivo
and in vitro is and has been available for some time, as I will show in Part III
of this series. Whether the CDC will ever be
convinced of that, is another story.
The last sentence of the statement is also somewhat misleading. In fact, the
Joint Statement issued by the AAP and the PHS in July 1999
"established the goal of removing the vaccine
preservative thimerosal as soon as possible from vaccines routinely recommended
So in 2011, thimerosal has indeed not
been removed from “vaccines”. It has been
mostly eliminated from pediatric
vaccines with some still containing traces of the preservative. Adult
vaccines and a few pediatric inactivated influenza vaccines currently available
in the United States contain as much of the preservative as they did before
The above suggests that each of the three sentences of the most visible CDC
information on thimerosal in vaccines is not exactly accurate.
Whether the Public Health Service agencies, the American Academy of Pediatrics,
and vaccine manufacturers agreed
whole-heartedly or had to agree is
another story that will be discussed later.
The FDA licenses vaccines and is at least in theory ultimately responsible for
An enormous amount of information about thimerosal on the FDA web site starts
with information not too different from that on the CDC web site except that the
FDA specifies that thimerosal was removed from
“all vaccines routinely recommended for children 6 years of age and younger”.
Thimerosal is a mercury-containing organic compound (an organomercurial).
Since the 1930s, it has been widely used as a preservative in a number of
biological and drug products, including many vaccines, to help prevent
potentially life threatening contamination with harmful microbes. 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 had
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.
Thimerosal has been removed from or reduced to trace amounts in all vaccines
routinely recommended for children 6 years of age and younger, with the
exception of inactivated influenza vaccine. A preservative-free version of
the inactivated influenza vaccine (contains trace amounts of thimerosal) is
available in limited supply at this time for use in infants, children and
Unlike the CDC, the FDA discussion of the subject is so exhaustive that one must
wonder whether the goal was information or a veiled attempt at justification and
The United States Code of Federal Regulations (CFR) actually
required the addition of a preservative
to multi-dose vials of vaccines in January 1968.
“Products in multi-dose containers shall contain a preservative, except that
a preservative need not be added to Yellow Fever Vaccine; Polio-virus
Vaccine, Live Oral; viral vaccine labeled for use with the jet injector;
dried vaccines when the accompanying diluent contains a preservative; or to
an Allergenic Product in 50 percent or more volume (v/v) glycerin. [21 CFR
The CFR specified that the preservative used
[s]hall be sufficiently non-toxic so that the amount present in the
recommended dose of the product will not be toxic to the recipient, and in
combination used it shall not denature the specific substance in the product
to result in a decrease below the minimal acceptable potency within the
dating period when stored at the recommended temperature. [21 CFR
There were also several
problems with the FDA statement. For the sake of brevity, only two will be
Under “Thimerosal as a preservative”, the FDA states:
“Prior to its introduction in the 1930’s, data were available in several
animal species and humans providing evidence for its safety and
effectiveness as a preservative (Powell and Jamieson 1931). Since then,
thimerosal has been the subject of several studies (see
) and has a long record of safe and effective use preventing
bacterial and fungal contamination of vaccines, with no ill effects
established other than minor local reactions at the site of injection”
The statement suggests that before thimerosal was added to vaccines, Powell and
Jamieson had shown that it was safe and effective. This is not exactly true
because the FDA clearly states in the same document that Powell and Jamieson’s
1931 study “was not specifically designed to
examine toxicity; 7 of 22 subjects were observed for only one day, the specific
clinical assessments were not described, and no laboratory studies were
And then there is the mention about thimerosal being the subject of “several
studies” and the annotation “see Bibliography” immediately followed by
“and has a long record of safe and effective
use preventing bacterial and fungal contamination of vaccines”, all in a
chapter about “Thimerosal in Vaccines”.
Unlike most readers in a rush, I clicked on “Bibliography” to look at those
studies I had never heard about. They were listed under the title:
“Studies on Safety and Effectiveness of Thimerosal”
The words “in vaccines” had disappeared and there were only 8 studies listed.
The very first two studies were published in 1974, some 43 years after Powell
and Jamieson and the most recent one, on preservatives in nasal preparations was
published in 1989, over twenty years ago. Study # 3 was on urinary cytology and
studies # 4, 5, 6 and 8 were on ophthalmological preparations. The two 1974
studies (# 2 and 7) dealt with development and standardization of the
preservative in general.
There was in fact no study about the safety and efficacy of thimerosal in
The second unconvincing FDA statement was under “Thimerosal Toxicity”. After
listing the many known instances of toxicity of the preservative, the FDA
decided to “prove” that thimerosal was safe by quoting a single reference, the
2002 study in Lancet by Pichichero et al.
The FDA proposed that the study proved that
“Blood levels of mercury did not exceed safety guidelines for methyl mercury
for all infants in these studies. Further, mercury was cleared from the
blood in infants exposed to thimerosal faster than would be predicted for
methyl mercury; infants excreted significant amounts of mercury in stool
after thimerosal exposure, thus removing mercury from their bodies. These
results suggest that there are differences in the way that thimerosal and
methyl mercury are distributed, metabolized, and excreted. Thimerosal
appears to be removed from the blood and body more rapidly than methyl
In fact, the study had several limitations affecting its conclusions:
- Only 40 infants who received TCV were included, 20 aged 2 months and 20
aged 6 months
- Just 21 infants who received thimerosal-free vaccines were used as
- The injected mercury was judged as a
range of mean mercury doses
- Blood draws were done conveniently
when the parents were able to bring the infants back
- Among Hg-exposed infants, blood samples from twelve 2-month-old were
collected from 8 and 21 days after vaccination and blood samples from
thirteen 6-month-old infants were collected from 8 to 27 days after
vaccination, when in all probability the Hg was no longer in the blood and
had settled in tissues including the brain
- The half life of thimerosal mercury, that seemed to have impressed
someone at the FDA, resulted from pharmacokinetic calculations whose
description was peppered with statements such as:
we developed a prediction, the expected
concentrations, half-lives of mercury ranging from 1 day to 45 days, we
assumed, elimination of mercury from blood followed a single compartment
model with first-order kinetics, possible half-life, the difference between
the predicted and actual recorded concentrations in blood, reliable
quantitation, and assumption that errors…
The extensive statement on the FDA web site did not include the most important
fact of all: A safe range of level of exposure to ethyl mercury.
It is worth mentioning that in spite of the present obsession with the subject,
responsible agencies have yet to agree on the supposedly safe levels for
methyl mercury: The EPA estimate of 0.1
µg/kg body weight/day is only a fraction of the WHO estimate of 0.47 µg/kg body
The FDA information included conclusions and recommendations by the Immunization
Safety Review Committee of the Institute of Medicine.
In October 2001, the committee concluded:
Among other things, the committee recommended, “that full consideration be given
by appropriate professional societies and government agencies to removing
thimerosal from vaccines administered to infants, children, or pregnant women in
the United States” and “that appropriate professional societies and governmental
agencies review their policies about the non-vaccine biological and
pharmaceutical products that contain thimerosal and are used by infants,
children, and pregnant women in the United States.”
- That although the hypothesis that exposure to thimerosal-containing
vaccines could be associated with neurodevelopmental disorders is not
established and rests on indirect and incomplete information, primarily from
analogies with methylmercury and levels of maximum mercury exposure from
vaccines given in children, the hypothesis is biologically plausible.
- That the evidence is inadequate to accept or reject a causal
relationship between thimerosal exposures from childhood vaccines and the
neurodevelopmental disorders of autism, ADHD, and speech or language delay.
Unfortunately in 2004, with thousands of cases of autism having been filed, the
same IOM committee decided, based on epidemiological studies that the “body of
evidence favors rejection of a causal relationship between thimerosal-containing
vaccines and autism, and that hypotheses generated to date concerning a
biological mechanism for such causality are theoretical only.”
Multiple articles criticizing the above-mentioned epidemiological studies from
Sweden, Denmark and the US have been published, including several by this
For those interested, a bibliography review of adverse reports related to
thimerosal was provided in a press release on March 17, 2002 by the well-known
law firm of Waters and Kraus. [http://www.vaccinationnews.com/DailyNews/March2002/Waters%2526KrausPressRelease3-17-02.htm]
Chronology of Thimerosal in Vaccines
In 1927, Morris Kharasch an Organic Chemist filed a patent application for an
alkyl mercuric sulfur compound with “potential” antiseptic and antibacterial
properties and assigns it to Eli Lilly and Co.
Two years later, Eli Lilly & Co. registered the product under the trade name
[Other names for ethylmercurithiosalicylate sodium are Thimerasol, Thiomerosal;
Thiomersal; Thimersalate; Thiomersalate; Merfamin; Merthiolate sodium; Mertorgan;
Merzonin and Sodium ethylmercuric thiosalicylate …]
Thimerosal is 49.6 percent mercury by weight and is metabolized into
ethylmercury and thiosalicylate.
As mentioned earlier, thimerosal has been the preferred preservative in vaccines
since the late 1930s supposedly because of its ability to prevent contamination
of multiple-dose vials by killing pathogenic organisms and fungi.
Years ago, I proposed that thimerosal was really added to vaccines to prevent
contamination on the production line and not in the doctor’s office. In the fall
of 2004, thousands of doses of influenza vaccine at Chiron Labs in the UK were
condemned and discarded because of contamination with Serratia Marascans.
The FDA had found “serious problems of
bacterial contamination” at the influenza vaccine plant in England in
2003, “16 months before British regulators
effectively closed the site and impounded its flu shots because of fears they
For 50 years, we pediatricians obediently used thimerosal-laced vaccines and
said nothing. Why we were fooled for so long will be explained later.
In 1980 and for reasons not as yet completely clear, the FDA suddenly started
examining over-the-counter (OTC) products containing thimerosal. Citing concerns
about toxicity and inefficacy, the agency then began banning some OTC thimerosal-containing
ointments and topical products.
In 1991, world-renowned vaccine developer Maurice Hilleman PhD sent a memo to
Dr. Gordon Douglas, Head of Merck’s Vaccine Division telling him that Sweden is
requiring thimerosal-free single-dose packaging of all products as soon as can
be reasonably achieved. Hilleman wrote: “For
babies: The 25 µg of mercury in a single 0.5 ml dose and extrapolated to a 6 lb
baby would be 25 X the adjusted Swedish daily allowance of 1.0 µg for a baby of
that size …. If 8 doses of thimerosal-containing vaccine were given in the first
six months of life (3 DPT, 2 HIB and 3 Hepatitis B), the 200 µg of mercury
given, say an average size of 12 lbs pounds would be about 87 X the Swedish
daily allowance of 2.3 µg of mercury for a baby of that size.”
Dr. Hilleman also told Douglas that in order of toxicity, methyl and ethyl salts
were most toxic. Mercury vapor was intermediate and inorganic salts least toxic.
[Interestingly, we still have “experts” in 2011 who still claim that ethyl
mercuric compounds are “safer” than methyl compounds.]
Merck and other manufacturers obliged and immediately produced mercury-free
vaccines for Scandinavian infants and children.
Our U.S. children were not as lucky. Not only did they keep getting thimerosal-laced
pediatric vaccines, they actually received more of them, including a dose in the
Six years later, New Jersey
Representative Frank Pallone cleverly attached a short amendment of 133 words to
the FDA reauthorization bill 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 in the list” within two years.
The Food and Drug Administration Modernization Act (FDAMA) was signed into law
on November 21, 1997.
On October 22, 1998, the FDA ban on the use of several other OTC
mercury-containing compounds went into effect because A. the safety and
effectiveness of the mercury components had not been established and B. the
manufacturers had not submitted data to the contrary.
During the following months, the FDA’s best experts from the Center for
Biologics Evaluation and Research (CBER) researched and discussed the issue in
depth. After they were done, they had to acknowledge that because safety studies
about ethylmercury were non-existent and
because toxic levels of the compound were still unknown, they were unable to
determine how toxic the thimerosal concentrations of up to 0.01 percent in more
than 30 US-licensed vaccines were.
Even though they did not agree on its toxicity level, the FDA, the EPA and the
Agency for Toxic Substances and Disease Registry (ATSDR) knew much more about
methyl mercury toxicity.
After much deliberation, CBER decided to consider thimerosal’s toxicity in
reference to the EPA’s methyl mercury guidelines. It is then that it became
evident that the mercury content of pediatric vaccines administered during the
first six months of life exceeded the
EPA reference dose (RfD) for methyl mercury of 0.1 micrograms per kilogram body
weight per day (µg/kg/day).
With the FDAMA deadline of Nov. 27, 1999 approaching, things heated up.
Something needed to be urgently done concerning thimerosal in vaccines and more
specifically pediatric vaccines.
In early June 1999, Neal Halsey, MD, FAAP, chairman of the American Academy of
Pediatrics Committee on Infectious Diseases and Director of the Institute for
Vaccine Safety at Johns Hopkins University was invited to a meet with the FDA
team. At the meeting, he was provided with the latest findings and alerted about
the urgency to do something regarding the amounts of thimerosal in pediatric
Dr. Halsey became alarmed and discussed the subject with his committee and the
At a National Immunization Conference held on June 25, 1999, Dr. Halsey met with
key people at the CDC and realized that they were looking at the situation from
a totally different angle. They were mostly interested in safeguarding their
excellent vaccination programs while Halsey and most pediatricians were more
worried by the day about the serious ethical and legal implications of the
mercury in vaccines issue.
After much haggling the two sides agreed that:
1. Thimerosal had to be removed from pediatric vaccines.
2. A “careful” joint public statement by the Public Health Service (PHS) and the
American Academy of Pediatrics (AAP) would be issued to pre-empt the FDA
announcement scheduled for sometime in July (1999) and the inevitable press
frenzy it was certain to create.
On June 28, 1999, the Interagency Vaccine Group (IAG) held a conference to
review the updated FDA risk assessment information and created a special
workgroup to examine all thimerosal related matters. Meanwhile, officials from
the CDC immunization branch met in a hurry with their own toxicologists and with
the vaccine companies’ risk assessors.
Because of the urgency of the situation, Dr. Halsey and leading AAP officials
organized an “informal” meeting to be held on June 30, 1999 at the AAP offices
in Washington, D.C. and invited “everyone”. This avoided the long delays
required for a formal meeting.
Disagreements still existed between the organizations and even within the
organizations. The AAP committee on Infectious Diseases and the AAP committee on
Environmental Health were still as
divided on the issue as were the agencies and the Academy.
The proposed actions ranged from immediately stopping administration of all
vaccines containing thimerosal to infants six month-old or younger to
encouraging the elimination of thimerosal by vaccine manufacturers.
It was decided at the end of the long and tumultuous session that no statement
would be issued until after the July 4 weekend when a PHS and AAP unified public
statement would be released.
A good summary of that unified public statement by the PHS and the AAP can be
found in the July 14, 2000 MMWR. [http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4927a5.htm]
As formulated in the joint statement, the goal was to remove thimerosal from
vaccines routinely recommended for infants as soon as possible while reassuring
everyone that no evidence existed of any harm caused by low levels of thimerosal
The groups had at last agreed to remove thimerosal from pediatric vaccines but
very clearly, many had done so under duress.
Slowly, US babies received less and less thimerosal in their vaccines.
The 1999 decision had little economic effect on the manufacture of thimerosal
and of thimerosal-containing vaccines. Thimerosal is still being produced in
enormous quantities and millions of thimerosal-laced doses of vaccines are still
being packaged and shipped daily … to “Third World” countries.
I do not know how many of my pediatric colleagues are as upset as I am about
being duped into believing for so long that the quantities of mercury we
injected into infants and children were insignificant.
I know for sure that Dr. Neal Halsey was absolutely right when he said:
''In most vaccine containers, thimerosal is listed as a mercury derivative,
a hundredth of a percent. And what I believed, and what everybody else
believed, was that it was truly a trace, a biologically insignificant
amount. My honest belief is that if the labels had had the mercury content
in micrograms, this would have been uncovered years ago. But the fact is, no
one did the calculation.''
In the third slide of a power- point presentation titled “Commentary on
Potential Risk from Thimerosal for Infants”, Dr. Halsey mentioned that excellent
In the following slide, Dr. Halsey listed situations where thimerosal (in large
doses) was proved to be neurotoxic.
The rest of the presentation is full of useful information.
I find the following disturbing:
This last atrocious state of affairs is the subject of Part II of this series.
- That the CDC, the FDA and other organizations are still downplaying the
problem by stating that thimerosal “has been used since the 1930’s with no
convincing evidence of harm, except for local reactions”
- That some “experts” still insist on comparing the danger from injecting
TCV into infants to eating half a tuna fish sandwich
- That certain TCV vaccines that were not routinely administered during
pregnancy in the past, are now not only recommended but encouraged
- That when Scandinavian countries chose to remove mercury from vaccines,
US vaccine makers immediately complied yet never considered doing the same
for infants in the United States until forced to do so years later
- That to this day, vaccine companies are still producing millions of
doses of TCV and shipping them to "Third World" countries
The featured article on the World Health Organization (WHO) web site on March
15, 2011 was, as expected, about the “Japanese government taking appropriate
protective measures” by asking people living within 20 km of the Fukushima
Daiichi nuclear power plant to evacuate and those between 20 km and 30 km to
stay indoors in unventilated rooms. The detailed information about the
catastrophe was presented as several well written pages of questions and answers
starting with the all-important: “What is the current risk of radiation-related
health problems in Japan to those near the reactor at the time, and those in
other parts of Japan?”
WHO was doing what it was supposed to do!
It was responding to a health threat and informing everyone in a balanced
scientific and timely fashion!
It was acting responsibly!
In Part I of this series, I discussed the history of thimerosal in pediatric
vaccines in the United States. In this second part of the three-part series, I
will review the role played by the World Health Organization (WHO). Please note
that WHO uses the English name thiomersal (lower key) even though the product is
a trade name and should be capitalized. To avoid confusion, I did the same.
The World Health Organization was established on April 7, 1948, and has been
headquartered in Geneva, Switzerland ever since.
The present Director-General of WHO is Dr. Margaret Chan who was appointed
November 9, 2006 and will be serving through June 2012. Dr. Chan was suddenly
thrust into the limelight in 2009-2010 when a widespread outbreak of H1N1
influenza became a pandemic.
Even though WHO had promoted vaccination since the late forties without
difficulty, Dr. Gro Harlem Brundtland, the Director General in 1999, felt the
need to urgently create not one but two new committees that year:
Just having a SAGE committee must have been wonderful and comforting!
- The “Strategic Advisory Group of Experts” (SAGE) to provide guidance on
vaccines and biological agenda
- The “Global Advisory Committee on Vaccine Safety” (GACVS) “to respond
promptly, efficiently, and with scientific rigour to vaccine safety issues
of potential global importance.” [http://www.who.int/vaccine_safety/en/]
As to GACVS, it did respond to some vaccine issues and crises but as far as
doing something about the thimerosal in pediatric vaccines, the committee
labored to do nothing and to maintain the status quo.
until January 2000 for WHO to endorse the US PHS / AAP July 1999 statement
“regarding prospective phasing out of
thiomersal – a chemical compound containing mercury used in trace amounts in
certain vaccine manufacturing processes and as a vaccine preservative”
Unfortunately even that first sentence did not ring
true! Pre-1999 vaccines contained substantially more than trace amounts of
thimerosal for the simple reason that trace
amounts would have been useless as a preservative.
In the next sentence that started with "However",
WHO mentioned the 1930's and frankly outlined its stand:
“However, the Organization underlines the
importance of continuing to use currently available children vaccines containing
thiomersal. Thiomersal (also known as Thimerosal or mercurothiolate) has been
used since the 1930’s …”.[http://www.who.int/docstore/wer/pdf/2000/wer7502.pdf]
GACVS members are appointed to 3 year-terms but the
very first team served from September 1999 to December 2003. Members are not
compensated but WHO pays their expenses to get to and stay in Geneva,
Switzerland for the meetings.
The present 13-member committee includes a Chairman
from Switzerland and a Vice-chairman from the UK. The other members are from
France, Guatemala, UK, Philippines, South Africa, India, Canada, USA, Finland,
Indonesia and Italy.
The 23rd GACVS meeting in 11 years was held on December 8-9, 2010 to examine:
- new data related to the risk of intussusception after rotavirus
- new data on the safety of pandemic influenza A (H1N1) 2009 vaccines
- the experience of using yellow fever vaccines among HIV-positive people
- the experiences of 3 West African countries which are monitoring the
safety of a new meningitis A conjugate vaccine.
Thimerosal was not brought up!
GACVS first “assessed” the issue of thimerosal in vaccines in August 2000.
committee reviewed the subject several times after that but always reconfirmed
its early assurances that “the pharmacokinetic profile of ethyl mercury is
substantially different from that of methyl mercury”, “that the half-life of
ethyl mercury was short” and “that therefore the exposure to ethyl mercury in
blood was comparatively brief.”
In the United States, 2002 was a busy year,
second only to 1999, when it came to mercury and vaccines: Much of the
thimerasol had been removed from pediatric preparations; people were upset about
its past use and many families were filing for compensation for vaccine injury.
The Subcommittee on Human Rights and Wellness, Committee on Government Reform,
US House of Representatives was also holding meetings and its no-nonsense
chairman was rattling higher-ups in the regulatory agencies trying to know how
and why they allowed mercury to be injected into infants, since the 1930’s …[The
subcommittee reported in May of 2003-http://vaccines.procon.org/sourcefiles/Burton_Report.pdf]
In Geneva, Switzerland WHO was also busy. Parents with or without children
with autism were openly questioning how come mercury-containing pediatric
vaccines that had been nearly phased-out in the United States were being shipped
to “third-world” countries.
WHO needed to do something convincing and the Quality Assurance and Safety of
Biologicals Team called a big meeting for April 15 and 16 (2002). Invited were
directors from several “National Regulatory Authorities”, executives from the
vaccine industry and higher-ups at the WHO Secretariat.
April is lovely in Geneva and the meeting was well attended. Guest
participants included executives from nine vaccine companies from as far away as
the Far East, in addition to vaccine regulators from Brazil, Belgium, Cuba,
France, Germany, India, Indonesia, Italy, Switzerland and the United States.
Eleven directors represented the Secretariat.
The meeting’s comprehensive report was published under the peculiar title:
“WHO Informal Consultation on the impact of thiomersal on quality, safety and
efficacy of vaccines: Regulatory Perspective”
Reading the detailed, official and authoritative 11-page report, one had to
wonder how such a meeting could be described as an informal consultation.
At the time, I thought that an informal consultation was a quick exchange at the
19th hole that started: “By the way Joe, I have this kid with a rash and a
A month later, WHO released another much shorter document titled “WHO
Informal Meeting on Removal of Thiomersal from Vaccines and its Implication for
Global Vaccine Supply.”
Here again one must wonder how “informal” a meeting about “removal of
Thiomersal” and “Global Vaccine Supply” between higher-ups at the World Health
Organization and executives of vaccine companies can be?
The conclusions that were reached included phrases such as:
The report went on: “On analysis of the Pros and Cons of the various
alternatives, the group considered that the best option would be to maintain
acceptance of thiomersal in vaccines for the global market.”
- “The safety of vaccines containing thiomersal as a preservative has been
well established over 60 years…”
- “Thiomersal has proven to be highly effective…”
- “The demands by regulatory and other health authorities in
industrialized countries that thiomersal be removed from vaccines are not
believed to be based on scientific facts …
- “Obtaining regulatory approval for … involves complex activities …
- “WHO is concerned about the current situation whereby manufacturers in
developed countries have been forced to lower the thiomersal content of
their vaccines, and is now considering the implications of changing from
proven safe and effective practices, …”
- “The option of using single dose vaccine is not feasible for WHO…”
then listed the required actions necessary to ensure continued availability of
At the end, the committee members not surprisingly “supported WHO’s plan to
recommend continued use of thiomersal in vaccines.”
- Clarify the regulatory situation
- Lobby Ministry of Health and senior regulators.
- Continue dialogue with EMEA, Korea and Canada
- Learn about the potential use of the USA export provisions
- Contact potential recipient countries (of bulk) to see if they would
play a bigger regulatory role and become finishers of the vaccines
- Develop a strong advocacy campaign to support ongoing use of thiomersal
- Involve developing country regulatory agencies in all these decisions.”
Nine years later, it
is clear that those two “informal” meetings killed any chance for anyone to ever
bring up the subject of thimerosal-free vaccines … again.
On June 13-14, 2002 the Strategic Advisory Group of Experts (SAGE) met for
its fourth annual meeting and decreed that “Two expert groups, the Global
Advisory Committee on Vaccine Safety and the US Institute of Medicine have
reviewed the data on the safety of thiomersal in vaccines, and have found no
scientific evidence of toxicity from thiomersal-containing vaccines. Therefore,
SAGE strongly affirms that vaccines containing thiomersal continue to be used
for maintaining safe immunization.”
On June 20-21, 2002, GACVS met to supposedly discuss the “Safety of
thiomersal-containing vaccines”. The report of the meeting was published in the
November 22, 2002 issue of WHO Weekly Epidemiological Record and strangely
started with a review of the whole charade …!
I should not be alone to question:
In 1999, concerns were raised in the United States of America regarding
exposure to mercury following immunization with thiomersal-containing
vaccines. This was based on the calculation that the cumulative amount of
mercury in infant immunization schedules potentially exceeds the recommended
threshold set by a USA government agency for methyl mercury. However,
thiomersal contains ethyl mercury, not methyl mercury.
Expert advice and data presented to GACVS indicate that the pharmacokinetics
of ethyl and methyl mercury are quite different. In particular, the
half-life of ethyl mercury is short (less than 1 week) compared with that of
methyl mercury (1.5 months). Thus, exposure to ethyl mercury in blood is
relatively brief. Ethyl mercury is actively excreted via the gut, whereas
methyl mercury accumulates in the body. Two independent epidemiological
studies have recently been completed in the United Kingdom. One was funded
by WHO (analysis of the General Practice Research Database (GPRD)), the
other by the United Kingdom Department of Health (analysis of the data set
of the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC). The GPRD
analysis suggests that there is no association between developmental delay,
particularly adverse neurological developmental outcomes or behavioural
problems, and thiomersal-containing diptheria–pertussis–tetanus (DPT)
vaccines given at 2, 3, and 4 months of age. These findings are supported by
the ALSPAC results. These studies give further support to the safety in
infants of thiomersal-containing vaccines in the amounts used in existing
On this basis, GACVS concluded that there is currently no evidence of
mercury toxicity in infants, children, or adults exposed to thiomersal in
vaccines. It also concluded that there is no reason to change current
immunization practices with thiomersal-containing vaccines on the grounds of
- How two studies, one funded by WHO and the other by the UK DOH can be
- How a study that just suggests that there is no association
between adverse neurological developmental outcomes and thimerosal-
containing DTP can be considered “irrefutable” and
How solely based on those two limited studies, GACVS can absolutely
conclude that there is “no evidence of mercury toxicity in infants,
children, or adults exposed to thiomersal in vaccines.”
It seemed also disingenuous for the committee to mention in 2002 “concerns”
raised in the United States in 1999, when in fact US health authorities had
acted on those concerns, yanked thimerosal out of pediatric vaccines and had
almost totally achieved that purpose, much before that GACVS meeting even
Between 2002 and 2008, the function of the Global Advisory Committee on Vaccine
Safety mostly involved shooting down research attempting to prove that
thimerosal-containing vaccines were in any way problematic.
In June 2003, the “vaccine safety” committee met and reported that:
“GACVS is maintaining a watching brief on the safety of thiomersal-containing
vaccines. There is insufficient evidence to reach definite conclusions
regarding the safety of thiomersal in possible special risk groups, notably
malnourished infants and premature or low-birth-weight newborn infants. It
is important to determine whether such individuals are at special risk, and
WHO should encourage further research on the matter relevant to the
developing world. Based on the most recent evidence, GACVS reported to WHO
that there is no scientific basis for changing current WHO recommendations
for thiomersal-containing vaccines, including administration of a birth dose
of hepatitis B vaccine and vaccination of low birth- weight infants where
As if one needed “definite conclusions” regarding
safety of thimerosal before providing already developed and available
mercury-free vaccines to malnourished or low-birth-weight preemies!
In December 2004, GACVS met to consider whether animal models could be applied
in order to better understand the association, if any, between thimerosal in
vaccines and neurobehavioral disorders in infants, children and adults. The
From an expert presentation made to the Committee and from several
publications, it is clear that: (i) no precise animal model exists that
closely mimics autism in humans, although animal models of deficit in social
play do exist; (ii) in the models available, susceptibility to
neurobehavioural disorders has a genetic basis; (iii) there are experimental
data to suggest that there is a link between autoimmune deficiency and
predisposition to autism (although this remains conjectural); and (iv) mice
born to mothers infected with human influenza virus have developed
neuropathologies similar to those described in association with autism.
So the committee traveled to Geneva, listened to “a
presentation”, read “several publications” and decided that:
The same thing happened in June 2005.
- No animal model existed anywhere on earth to test a link between autism
- Neurobehavioral disorders had a genetic basis and no other etiologies
- Autoimmune deficiency and mercury toxicity were mutually exclusive
Committee members flew in to review a recent pharmacokinetic study on the
mercury preservative and agreed that “the findings confirmed the view that
methyl mercury is not suitable for risk assessment of thiomersal” because “brain
concentrations of total mercury were threefold lower with thiomersal, compared
with methyl mercury.”
Not surprisingly, the committee decided that it
remained “of the view that there is no evidence supporting a causal
association between neurobehavioural disorders and thiomersal-containing
In June 2008, GACVS met once more to consider a study
about the pharmacokinetics of mercury in premature and low-birth-weight infants
who received a birth dose of hepatitis B vaccine containing thimerasol and
another about neuropsychological performance 10 years after immunization with
TCV. The latter study showed that higher thimerosal exposure through vaccines
caused lower scores on neuropsychological testing but the committee
discounted it because the differences in mean scores were small and only
detected in girls.
The committee explained that the studies were of “doubtful clinical relevance”
because they were not consistent with results from other ethyl mercury studies.
Three years later, I am still bewildered by the logic of that statement.
The members also claimed that the observed associations simply reflected “the
effect of chance”, an old cliché we seem to hear quite often in the United
At the end, the GACVS concluded that it maintained “the
view that there is no evidence supporting any change in WHO’s recommendations
for thiomersal-containing vaccines and the vaccination of low-birth-weight
infants where indicated.”
As will be evident in Part 3 of this series, there
were many relevant studies during that long period that were never reviewed by
Of course, there is no assurance that the committee would have found in any of
them the evidence it estimated to be enough “to support any change.”
In 2009 and 2010, GACVS was busy with the H1N1 “pandemic”.
When it had the chance, GACVS reviewed the “safety” of the HPV and rotavirus
vaccines among others.
The members evidently felt by then that the issue of mercury in vaccines for
“developing countries” had been discussed enough!
Many talk about the third world but few ever mention the first and second
So what are those worlds?
As much as I can tell, the "First World" refers to the developed industrial
countries within the “North American” and “Western European” sphere of
influence. These include obviously Canada, the United States and Western Europe,
in addition to Australia, New Zealand, Japan and Israel.
The “Second World” includes the old Eastern Bloc (Russia and Eastern Europe) and
The “Third World” includes the remaining countries of Asia, Africa, Oceania and
Latin America, possibly 70% of the world population and … growing.
In the United States, we are usually referring to huge
populations in the poorest and least developed countries of Africa when we
discuss health, hygiene, nutrition and vaccine policies in the Third World.
Even though OPEC countries are considered part of the third world, their
“Petro-Dollars” make them quite distinct.
Similarly prosperous countries in South America such as Brazil, Peru, Uruguay
and Argentina can hardly be compared to truly “underdeveloped” and
near-destitute nations when it comes to health.
For these countries, procuring a slightly more expensive unit dose vaccine for
their little ones cannot possibly be a big problem. It seems therefore strange
that representatives from those nations’ vaccine regulatory agencies regularly
meet in Geneva and still agree that thimerosal-containing vaccines in multi-dose
vials are best for infants regardless of size, for pregnant women and for
In Memoriam: Philip B Rudnick PhD ~ December 23, 2010
F. Edward Yazbak, MD, FAAP