Recent scientific evidence has begun to link the presence of thimerosal in childhood vaccines to autism and other childhood neurological and behavioral disorders.  Thimerosal is a preservative that contains mercury, a compound known to cause brain damage.  The U.S. FDA has encouraged pharmaceutical companies to remove thimerosal from their vaccines as soon as possible.  A product liability lawsuit may help injured children recover damages from this situation in the future, and attorneys are expected to organize such a class-action lawsuit.  The information that follows is from the FDA's Center for Biologics Evaluation and Research.  It contains information about the research on thimerosal and autism as well as information about the content of vaccines.

Tables

Table 1. Thimerosal Content of Vaccines Routinely Recommended for Children 6 Years of Age and Younger - (updated 7/18/2005)

Vaccine	Tradename (Manufacturer)*	Thimerosal Status Concentration**(Mercury)	Approval Date for Thimerosal Free or Thimerosal / Preservative Free (Trace Thimerosal)*** Formulation
DTaP	Infanrix (GSK)	Free	Never contained Thimerosal
	Daptacel (AP)	Free	Never contained Thimerosal
	Tripedia (AP)	Trace(<0.3 µg Hg/0.5mL dose)	03/07/01
DTaP-HepB-IPV	Pediarix (GSK)	Trace (<0.0125 µg Hg/0.5mL dose)	Never contained more than a Trace of Thimerosal
Pneumococcal conjugate	Prevnar (WL)	Free	Never contained Thimerosal
Inactivated Poliovirus	IPOL (AP)	Free	Never contained Thimerosal
Varicella (chicken pox)	Varivax (M)	Free	Never contained Thimerosal
Mumps, measles, and rubella	M-M-R-II (M)	Free	Never contained Thimerosal
Hepatitis B	Recombivax HB (M)	Free	08/27/99
	Engerix B (GSK)	Trace (<0.5 µg Hg/0.5mL dose)	03/28/00
Haemophilus influenzae type b conjugate (Hib)	ActHIB (AP)/OmniHIB (GSK)	Free	Never contained Thimerosal
	PedvaxHIB (M)	Free	08/99
	HibTITER, single dose (WL)1	Free	Never contained Thimerosal
Hib/Hepatitis B combination	Comvax (M)	Free	Never contained Thimerosal
Influenza	Fluzone (AP)	0.01% (12.5 µg/0.25 mL dose, 25 µg/0.5 mL dose)2
	Fluzone (AP)3 (no thimerosal)	Free	12/23/2004
	Fluvirin (Chiron/Evans)	0.01% (25 µg/0.5 mL dose)
	Fluvirin (Chiron/Evans) (Preservative Free)	Trace (<1ug Hg/0.5mL dose)	09/28/01
Influenza, live	FluMist4 (MedImmune)	Free	Never contained Thimerosal

Manufacturer abbreviations:
GSK = GlaxoSmithKline; WL = Wyeth Lederle; AP = Aventis Pasteur; M = Merck.
** Thimerosal is approximately 50% mercury (Hg) by weight. A 0.01% solution (1 part per 10,000) of thimerosal contains 50 µg of Hg per 1 mL dose or 25 µg of Hg per 0.5 mL dose.
*** The term "trace" has been taken in this context to mean 1 microgram of mercury per dose or less.
1 HibTiITER was also manufactured in thimerosal-preservative containing multidose vials but these were no longer available after 2002.
2 Children 6 months old to less than 3 years of age receive a half-dose of vaccine, i.e., 0.25 mL; children 3 years of age and older receive 0.5 mL.
3 A trace thimerosal containing formulation of Fluzone was approved on 9/14/02 and has been replaced with the formulation without thimerosal.
4 FluMist is not indicated for children less than 5 years of age.

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Table 2: Preservatives Used in U.S. Licensed Vaccines

Preservative	Vaccine Examples (Tradename; Manufacturer*)
Thimerosal	DT Td (several) TT (several) Influenza (several)
2-phenoxyethanol and formaldehyde	IPV (IPOL; AP) DTaP (Daptacel; AP)
Phenol	Typhoid Vi Polysaccharide (Typhim Vi; AP) Pneumococcal Polysaccharide (Pneumovax 23; M)
Benzethonium chloride (Phemerol)	Anthrax (B)
2-phenoxyethanol	DTaP (Infanrix; GSK) Hepatitis A (Havrix; GSK) Hepatitis A/Hepatitis B (Twinrix; GSK)

*Manufacturer abbreviations:
GSK = Glaxo SmithKline; WL = Wyeth Lederle; AP = Aventis Pasteur; M = Merck; B=Bioport.

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Table 3: Thimerosal and Expanded List of Vaccines - (updated 7/5/2005)

Thimerosal Content in Currently Manufactured U.S. Licensed Vaccines
Vaccine	Trade Name	Manufacturer	Thimerosal Concentration1	Mercury
Anthrax	Anthrax vaccine	BioPort Corporation	0	0
DTaP	Tripedia2	Aventis Pasteur, Inc	< 0.0012%	0.3 µg/0.5 mL dose
	Infanrix	GlaxoSmithKline	0	0
	Daptacel	Aventis Pasteur, Ltd	0	0
DTaP-HepB-IPV	Pediarix	GlaxoSmithKline	< 0.000005%	< 0.0125 µg/0.5 mL dose
DT	No Trade Name	Aventis Pasteur, Inc	< 0.00012% (single dose)	< 0.3 µg/0.5mL dose
		Aventis Pasteur, Ltd3	0.01%	25 µg/0.5 mL dose
Td	No Trade Name	Mass Public Health	0.0033%	8.3 µg/0.5 mL dose
	Decavac	Aventis Pasteur Inc	<=0.00012%	0.3 µg mercury/0.5 ml dose
	No Trade Name	Aventis Pasteur, Ltd	0	0
Tdap	Adacel	Aventis Pasteur, Ltd	0	0
	Boostrix	GlaxoSmithKline	0	0
TT	No Trade Name	Aventis Pasteur Inc	0.01%	25 µg/0.5 mL dose
Hib	ActHIB/OmniHIB4	Aventis Pasteur, SA	0	0
	HibTITER	Wyeth-Lederle	0	0
	PedvaxHIB liquid	Merck	0	0
Hib/HepB	COMVAX5	Merck	0	0
Hepatitis B	Engerix-B Pediatric/adolescent Adult	GlaxoSmithKline	< 0.0002% < 0.0002%	< 0.5 µg/0.5 mL dose <1µg/1 ml dose
	Recombivax HB5 Pediatric/adolescent Adult (adolescent) Dialysis	Merck	0 0 0	0 0 0
Hepatitis A	Havrix	GlaxoSmithKline	0	0
	Vaqta	Merck	0	0
HepA/HepB	Twinrix	GlaxoSmithKline	< 0.0002%	< 1 µg/1mL dose
IPV	IPOL	Aventis Pasteur, SA	0	0
	Poliovax	Aventis Pasteur, Ltd	0	0
Influenza	Fluzone6	Aventis Pasteur, Inc	0.01%	25 µg/0.5 mL dose
	Fluvirin	Evans	0.01%	25 µg/0.5 ml dose
	Fluzone (no thimerosal)	Aventis Pasteur, Inc	0	0
	Fluvirin (Preservative Free)	Evans	< 0.0004%	< 1 µg/0.5 mL dose
Influenza, live	FluMist	MedImmune	0	0
Japanese Encephalitis7	JE-VAX	BIKEN	0.007%	35 µg/1.0mL dose 17.5 µg/0.5 mL dose
MMR	MMR-II	Merck	0	0
Meningococcal	Menomune A, C, AC and A/C/Y/W-135	Aventis Pasteur, Inc	0.01% (multidose) 0 (single dose)	25 µg/0.5 dose 0
	Menactra A, C, Y and W-135	Aventis Pasteur, Inc	0	0
Pneumococcal	Prevnar (Pneumo Conjugate)	Lederle Laboratories	0	0
	Pneumovax 23	Merck	0	0
Rabies	IMOVAX	Aventis Pasteur, SA	0	0
	Rabavert	Chiron Behring	0	0
Typhoid Fever	Typhim Vi	Aventis Pasteur, SA	0	0
	Typhoid Ty21a	Berna Biotech, Ltd	0	0
Varicella	Varivax	Merck	0	0
Yellow Fever	Y-F-Vax	Aventis Pasteur, Inc	0	0
Table Footnotes Thimerosal is approximately 50% mercury (Hg) by weight. A 0.01% solution (1 part per 10,000) of thimerosal contains 50 µg of Hg per 1 ml dose or 25 µg of Hg per 0.5 ml dose. Aventis Pasteur’s Tripedia may be used to reconstitute ActHib to form TriHIBit. TriHIBit is indicated for use in children 15 to 18 months of age. This vaccine is not marketed in the US. OmniHIB is manufactured by Aventis Pasteur but distributed by GlaxoSmithKline. COMVAX is not licensed for use under 6 weeks of age because of decreased response to the Hib component. Children under 3 years of age receive a half-dose of vaccine, i.e., 0.25 mL (12.5 µg mercury/dose.) JE-VAX is manufactured by BIKEN and distributed by Aventis Pasteur. Children 1 to 3 years of age receive a half-dose of vaccine, i.e., 0.5 mL (17.5 µg mercury/dose).

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References

1. Agency for Toxic Substances and Disease Registry. Toxicological profile for mercury. Atlanta, GA: Agency for Toxic Substances and Disease Registry;1999.

2. Axton JMH. Six cases of poisoning after a parenteral organic mercurial compound (merthiolate). Postgrad Med J 1972;48:417-421.

3. Bakir F, Damlugi SF, Amin-Zaki L, Murtadha M, Khalidi A, Al-Rawi NY, Tikriti S, Dhahir HI, Clarkson TW, Smith JC, Doherty RA. Methylmercury poisoning in Iraq. Science 1973;181:230-241.

4. Ball LK, Ball R, Pratt RD. An assessment of thimerosal use in childhood vaccines. Pediatrics 2001;1147-1154.

5. Bernard S, Enayati A, Redwood L, Roger H, and Binstock T. Med. Hypotheses 2001, 56: 462-471.

6. Bernier RH, Frank JA, Nolan TF. Abscesses complicating DTP vaccination. Am J Dis Child 1981;135:826-828.

7. Blair AMJN, Clark B, Clarke, AJ, Wood, P. Tissue Concentrations of Mercury after Chronic Dosing of Squirrel Monkeys with Thimerosal. Toxicology 1975;3:171-1766.

8. Centers for Disease Control and Prevention. Notice to Readers: Thimerosal in Vaccines: A Joint Statement of the American Academy of Pediatrics and the Public Health Service. Morb Mort Wkly Rep 1999;48:563-565.

9. Cox NH, Forsyth A. Thimerosal allergy and vaccination reactions. Contact Dermatitis 1988;18:229-233.

10. Davidson PW, Myers GJ, Cox C, Axtell C, Shamlaye C, Sloan-Reeves J, Cernichiari E, Needham L, Choi A, Wang Y, Berlin M, Clarkson TW. Effects of prenatal and postnatal methylmercury exposure from fish consumption on neurodevelopment: Outcomes at 66 months of age in the Seychelles child development study. JAMA 1998;280:701-707.

11. Fagan DG, Pritchard JS, Clarkson TW, Greenwood MR. Organ mercury levels in infants with omphaloceles treated with organic mercurial antiseptic. Arch Dis Child 1977;52:962-964.

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17. Harada M. Minamata disease: Methylmercury poisoning in Japan caused by environmental pollution. Crit Rev Toxicol 1995;25:1-24.

18. IOM (Institute of Medicine). Thimerosal-containing vaccines and neurodevelopmental disorders. Washington DC: National Academy Press; 2001.

19. Lowell HJ, Burgess S, Shenoy S, Peters M, Howard TK. Mercury poisoning associated with hepatitis B immunoglobulin. Lancet 1996:347:480.

20. Magos L, Brown AW, Sparrow S, Bailey E, Snowden RT, Skipp WR. The comparative toxicology of ethyl- and methylmercury. Arch Toxicol 1985,57:260-267.

21. Mahaffey KR, Rice G, et al. An Assessment of Exposure to Mercury in the United States: Mercury Study Report to Congress. Washington, DC: U.S. Environmental Protections Agency; 1997. Document EPA-452/R097-006.

22. Mahaffey KR. Methylmercury: A new look at the risks. Public Health Rep 1999;114:397-413

23. Matheson DS, Clarkson TW, Gelfand EW. Mercury toxicity (acrodynia) induced by long-term injection of gammaglobulin. J Pediatr 1980: 97:153-155Moller H. All these positive tests to thimerosal. Contact Dermatitis 1994; 31:209-213.

24. Pfab R, Muckter H, Roider G, Zilker T. Clinical Course of Severe Poisoning with Thiomersal. Clin Toxicol 1996;34:453-460.

25. Powell HM, Jamieson WA. Merthiolate as a Germicide. Am J Hyg 1931;13:296-310.

26. Rohyans J, Walson PD, Wood GA, MacDonald WA. Mercury toxicity following merthiolate ear irrigations. J Pediatr 1994;104:311-313.

27. Simon PA, Chen RT, Elliot JA, Schwartz B. Outbreak of pyogenic abscesses after diphtheria and tetanus toxoids and pertussis vaccine. Pediatr Infect Dis J 1993;12:368-371.

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30. World Health Organization. Trace elements and human nutrition and health. Geneva: World Health Organization;1996:209.

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Bibliography

Studies on Safety and Effectiveness of Thimerosal:

1. Batts AH, Narriott C, Martin GP, et al. The effect of some preservatives used in nasal preparations on mucociliary clearance. Journal of Pharmacy and Pharmacology 1989; 41:156-159.

2. Batty I, Harris E, Gasson A. Preservatives and biological reagents. Developments in Biological Standardization 1974;24:131-142.

3. Beyer-Boon ME, Arntz PW, Kirk RS. A comparison of thimerosal and 50% alcohol as preservatives in urinary cytology. Journal of Clinical Pathology 1979;32:168-170.

4. Gasset AR, Itoi M, Ishii Y, Ramer RM. Teratogenicities of ophthalmic drugs. II. Teratogenicites and tissue accumulation of thimerosal. Archives of Ophthalmology 1975;93:52-55.

5. Goldman KN, Centifanta Y, Kaufman HF, et al. Prevention of surface bacterial contamination of donor corneas. Archives of Ophthalmology 1978;96:2277-2280.

6. Keeven J, Wrobel S, Portoles M, et al. Evaluating the preservative effectiveness of RGP lens care solutions. Contact Lens Association of Ophthalmologists Journal 1995;21:238-241.

7. Naito R, Itoh T, Hasegawa E, et al. Bronopol as a substitute for thimerosal. Developments in Biological Standardization 1974;24:39-48.

8. Wozniak-Parnowska W, Krowczynski L. New approach to preserving eye drops. Pharmacy International 1981;2(4):91-94.

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¹   FDA’s guideline is based in part on a maximum tolerable daily intake of 30 µg/day of methylmercury from the diet; for purposes of comparison this would translate to approximately 0.43 micrograms/kg/day for a 70 kg adult. The FDA recommends that pregnant women, women of childbearing age who may become pregnant, nursing mothers and young children do not consume certain kinds of fish that may contain high levels of methylmercury (i.e., shark, swordfish, king mackerel, and tilefish); see http://www.cfsan.fda.gov/~lrd/tphgfish.html

²   The WHO guideline is expressed as 3.3 µg/kg/week and has been converted to a daily dose for purposes of comparison.

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Updated July 18, 2005

With the exception of the section labeled "The Problem" this document was produced by the FDA / Center for Biologics Evaluation and Research in July of 2005.  This document is in the public domain as a work-for-hire created by U.S. Government employees and can be freely reproduced.