Thimerosal should be stored at room temperature
protected from light.
It is reportedly stable in air but not in
sunlight.
SOLUTION STABILITY:
The rate of oxidation of thimerosal in solution is
greatly increased by traces of copper ions. In slightly acidic solution
thimerosal may be precipitated as the corresponding acid which undergoes slow
decomposition with the formation of insoluble products.
SYNTHESIS:
Thimerosal is made from the combination of ethyl
mercuric chloride, thiosalicylic acid, sodium hydroxide and ethanol.
Thimerosal Is Composed of Thiosalicylic Acid And Ethyl Mercury (1,2)
Concern About The Safety Of Thimerosal
The Food and Drug Modernization Act (FDAMA) was
enacted on November 21, 1997. Section 413 of the FDAMA is entitled Food and
Drug Administration Study of Mercury Compounds in Drugs and Food.
The FDAMA required the FDA to (1) Compile a list
of drugs and foods that contain intentionally introduced mercury compounds
(e.g. mercurous chloride, mercuric chloride, phenylmercuric acetate,
thimerosal), and (2) provide a quantitative and qualitative analysis of the
mercury compounds in this list.
The Food And Drug Administrations Response To
FDAMA (3)
The FDA is aware that mercury compounds (e.g.
phenyl-mercuric acetate and thimerosal) are used as a preservative in OTC
nasal solution products, prescription opthalmic drug products, and biological
products including vaccines, immunoglobulins, antivenins, and skin test
antigens.
Over 100 nasal spray/solutions, eye and topical
products contain thimerosal-10 nose drop/spray products, 5 eye products, 2 ear
products, 20 injectable products including toxoids, vaccines, antivenins.
By The First Grade Children In The U.S. Receive
21 Vaccinations,
Many Of Which Contain Thimerosal
Vaccines And Immunoglobulins Which Contain
Thimerosal (4)
Birth: Hep B-first shot;
2 Months: DTaP-first; Polio-first;
Hib-first; Hep B-second;
4 Months: DTaP-second; Polio-second; Hib-second;
6 Months: DTaP-third; Polio-third; Hib-third;
12 Months: Varicella-fist; MMR-first; Hib-fourth
15 Months: Hep B-third; DTaP-fourth
4 Years: MMR-second; Polio-fourth
5 Years: DTaP-fifth
Limiting Infant Exposure to Thimerosal in
Vaccines and Other Sources of Mercury (5)
Exposure to ethylmercury from vaccines containing
thimerosal in the first 6 months of life ranges from 0 to 187 µg based on
which vaccines are administered.
If all thimerosal containing vaccines are given,
the total exposures exceed the EPA guidelines, and possibly other guidelines,
for the smallest infants.
Clinicians are uncertain as to how much mercury
can be safely given at 1 time when multiple thimerosal-containing vaccines are
administered simultaneously.
According to the Environmental Protection Agency,
the average adult dose thought to be able to be consumed on a daily basis
without harm is 0.1µg/kg per day.
Could infants receiving multiple thimerosal
containing vaccines during their first 6 months of life exceed this daily dose
presumed to be safe by the EPA?
6 months x 30 days/month = 180 days; 187 µg ?
180 days = 1.04 µg/day
The average 6 month old infant weighs 7 kg;;
1.04µg/day ? 7 kg = 0.15 µg/kg per day
On the days when the vaccines are actually
administered, the exposure is much higher
Joint Statement Of The American Academy of
Pediatrics (AAP) and The Public Health Service (PHS) On July 7, 1999 Regarding
The Use And Safety Of Thimerosal In Vaccines. (6)
The Food and Drug Administration (FDA)
Modernization Act of 1997 called for the FDA to review and assess the risk of
all mercury containing food and drugs. In line with this review, U.S. vaccine
manufacturers responded to a December 1998 and April 1999 FDA request to
provide more detailed information about the thimerosal content of their
preparations which include this compound as a preservative.
Thimerosal has been used as an additive to
biologics and vaccines since the 1930's because it is very effective in
killing bacteria used in several vaccines and in preventing bacterial
contamination, particularly in opened multi-dose containers. Some but not all
of the vaccines recommended routinely for children in the U.S.contain
thimerosal.
There is a significant safety margin incorporated
into all the acceptable mercury exposure limits. Furthermore, there are no
data or evidence of any harm caused by the level of exposure that some
children may have encountered in following the existing immunization
schedule.
Infants and children who have received
thimerosal-containing vaccines do not need to be tested for mercury
exposure.The recognition that some children could be exposed to a cumulative
level of mercury over the first six months of life that exceeds one of the
federal guidelines on methyl mercury now requires a weighing of two different
types of risks when vaccinating infants.
"On the one hand, there is the known serious risk
of diseases and deaths caused by failure to immunize our infants against
vaccine-preventable infectious diseases; on the other, there is the unknown
and probably much smaller risk, if any, of neuro-developmental effects posed
by exposure to thimerosal.The large risks of not vaccinating children far
outweigh the unknown and probably much smaller risk, if any, of cumulative
exposure to thimerosal-containing vaccines over the first six months of
life. Nevertheless, because any potential risk is of concern, the Public
Health Service, the American Academy of Pediatrics, and vaccine manufacturers
agree that thimerosal-containing vaccines should be removed as soon as
possible.
Similar conclusions were reached this year in a
meeting attended by European regulatory agencies, the European vaccine
manufacturers, and the US FDA which examined the use of thimerosal-containing
vaccines produced or sold in European countries.
The US Public Health Service and the American
Academy of Pediatrics are working collaboratively to assure that the
replacement of thimerosal-containing vaccines takes place as expeditiously as
possible while at the same time ensuring that our high vaccination coverage
levels and their associated low disease levels throughout our entire childhood
population are maintained.
References
1. The Merck Index, 12th ed., p. 1590, #9451 (1996).
2. Martindale The Extra Pharmacopoeia, 30th ed., 804 (1993).
3. Federal Register, December 14, 1998, Vol. 63,
68775.
ALL INFORMATION, DATA, AND
MATERIAL CONTAINED, PRESENTED, OR PROVIDED HERE IS FOR GENERAL INFORMATION
PURPOSES ONLY AND IS NOT TO BE CONSTRUED AS REFLECTING THE KNOWLEDGE OR OPINIONS
OF THE PUBLISHER, AND IS NOT TO BE CONSTRUED OR INTENDED AS PROVIDING MEDICAL OR
LEGAL ADVICE. THE DECISION WHETHER OR NOT TO VACCINATE IS AN IMPORTANT AND
COMPLEX ISSUE AND SHOULD BE MADE BY YOU, AND YOU ALONE, IN CONSULTATION WITH
YOUR HEALTH CARE PROVIDER.
"A foolish faith in authority is the worst enemy of truth."
-- Albert Einstein, letter to a friend, 1901
"I know of no safe depository of the ultimate powers of the society but the people themselves, and if we think them not enlightened enough to exercise control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education."
-- Thomas Jefferson, letter to William C. Jarvis, September 28, 1820
"What's the point of vaccination if it doesn't protect you from the unvaccinated?"
-- Sandy Gottstein
"Who gets to decide what the greater good is and how many will be sacrificed to it?"